Compressed Natural Gas
Supplement
Service Manual for
Mixer Vehicles
1565578
© 2016 McNeilus Truck and Manufacturing, Inc.
Rev. 0218
Disclaimer:
This manual must not be used to repair your vehicle. Repair information is available by calling McNeilus Customer Service at
(888) 686-7278.
The information in this Manual will be your guide to operation, service, and basic maintenance for this equipment.
All information, illustrations, and specifications in this manual are based on the information available at the time this manual was
published. The illustrations used in this manual are intended as representative reference views only. Because of our continuous
product improvement policy, we may modify information, illustrations, and/or specifications to explain and/or exemplify a product,
service, or maintenance improvement. We reserve the right to make any change at any time without notice. Go to
www.streetsmartparts.com for current information.
No part of this publication may be reproduced by any means - graphic, electronic, or mechanical, including photocopying,
recording, taping, or information storage and retrieval systems for any use or purpose - without the written permission of
McNeilus Truck and Manufacturing, Inc.
For assistance in ordering OSHA Publications, contact:
U.S. Department of Labor/OSHA
OSHA Publications
P.O. Box 37535
Washington, D.C. 20210
Telephone: 202-693-1888 • Fax: 202-693-2498
Table of Contents
Section 1: General Information Section 2: Safety Section 3: General CNG Components
Section 4: CNG Fueling and Defueling Section 5: Preventive Maintenance
Section 6: Component Remove and Replace
Section 7: Troubleshooting
Section 8: Index
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General Information
1
Thank You
Thank you for placing your confidence in our product. With proper maintenance, you will have a product that will serve your
company for a number of years.
This manual is your guide for general and maintenance information of the CNG system. For service and maintenance of the
vehicle, please refer to the service manual for that vehicle. For parts information, manuals can be purchased through your
McNeilus Parts and Service branch location. Please keep this manual in a safe place.
Protect your investment in McNeilus equipment. Do not jeopardize your warranty. Use only genuine McNeilus replacement
parts. Original McNeilus Parts ensure the finest quality, the longest life and proper, reliable operation.
We encourage you to call anytime you have questions or require assistance with our product. We also welcome your
suggestions and ideas. Always have your model and serial number, if applicable, ready when calling for information and parts.
© 2016 McNeilus Truck and Manufacturing, Inc.
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CNG — Service Manual
General Information
Table of Contents
1.0 PURPOSE OF THIS MANUAL........................................................................................................................................... 1-3
1
2.0 PARTS AND SERVICE....................................................................................................................................................... 1-3
3.0 CORPORATE HEADQUARTERS...................................................................................................................................... 1-3
4.0 GLOSSARY........................................................................................................................................................................ 1-4
CNG — Service Manual
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© 2016 McNeilus Truck and Manufacturing, Inc.
General Information
1.0 Purpose of this Manual
2.0 Parts and Service
1.1 Introduction
Contact your McNeilus Parts and Service branch locations
to order parts, receive service information, or for other
assistance.
Your Mixer system may be equipped with Compressed
Natural Gas (CNG) fuel tanks. Vehicles with CNG are
designated as dedicated CNG vehicles which means
the vehicles are equipped with one fuel system and are
designed to operate on CNG. Use these instructions for
the safe operation, inspection, and maintenance of all CNG
tanks.
Contact by phone or visit www.streetsmartparts.com.
We have factory owned parts and service centers near you.
888-686-7278
Phone Number
State
CA
CT
FL
GA
IL
IN
MN
NY
OH
OH
PA
TX
TX
UT
WI
NOTE: Reference the chassis CNG manual and all other
available resources for additional information.
City
Colton
East Granby
Tampa
Villa Rica
Sugar Grove
Fort Wayne
Dodge Center
Bronx
Cincinnati
Columbus
Morgantown
Houston
Hutchins
West Valley City
Oshkosh
Canada
Ontario and Western Provinces
Quebec and Maritime Provinces
800-265-1089
800-996-4937
3.0 Corporate Headquarters
Contact McNeilus Truck and Manufacturing, Inc. directly at
our corporate headquarters at the following address, phone
number, and website.
McNeilus Truck and Manufacturing, Inc.
524 County Road 34 East
Dodge Center, MN 55927
Telephone: 507-374-6321
Corporate Website: www.mcneiluscompanies.com
Parts and Service Website: www.streetsmartparts.com
© 2016 McNeilus Truck and Manufacturing, Inc.
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CNG — Service Manual
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General Information
4.0 Glossary
MAWP - Maximum Allowable Working Pressure that the
CNG system may be pressurized to.
Defueling - Depletion of fuel from the CNG tank(s).
1
NGV - Natural gas vehicle. Any vehicle whose primary fuel
source is natural gas.
Diesel Gallon Equivalent (DGE) - The amount of natural
gas whose energy equals that of a single gallon
of automotive grade diesel fuel. Approximately
6.6 lbs. natural gas or 140 standard cubic feet
contains energy equivalent to one gallon of standard
automotive-grade diesel fuel.
Pressure Relief Device (PRD) - A thermally activated
device installed in direct contact with internal
pressure in each tank that will release the contained
gas in excess temperature (219°F).
Fuel Control Module - (Also known as Fuel Management
Module or FMM.) Displays the storage tank pressure
and output pressure. Controls the manual shut
off valve, and the fill receptacle and defueling
receptacle. Fuel pressure regulation occurs in the
Fuel Control Module.
Remote Fueling Receptacle - Some vehicles may be
equipped with additional remote fill receptacles
located at the front bumper, on the passenger side of
the vehicle, or as a rear fill port (located rearward on
the vehicle).
Safety Decals - Decals found on the fuel control module
and the vehicle that warn of hazards related to the
use of this equipment.
Fuel Storage Pod - Houses and protects the fuel tanks and
their associated hardware.
Fueling Receptacle - Is used for adding fuel to the
vehicle’s fuel tanks. The receptacle is located on the
front panel of the fuel control module. There are two
standard fueling receptacles: NGV1 and Transit Fill
(“Fast Fill”).
Service Pressure - Nominal tank pressure determined
when system is considered full, at 70°F gas
temperature.
High Pressure Gauge - Indicates fuel pressure being
supplied to the regulator. This gauge is located on
the front panel of the fuel control module.
Low Pressure Gauge - Indicates the fuel pressure exiting
the regulator and being supplied to the vehicle’s
engine. This gauge is located in the front panel of the
fuel control module.
Manual Shut-Off Valve - When activated in the shut-off
position (vertical with the arrow pointing down), fuel
is prohibited from flowing from the fuel tanks to the
vehicle’s engine. The valve is located on the front of
the fuel control module.
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© 2016 McNeilus Truck and Manufacturing, Inc.
2
Safety
Table of Contents
1.0 IMPORTANT SAFETY INFORMATION.............................................................................................................................. 2-3
1.1 Safety Notices........................................................................................................................................................... 2-3
1.2 Safety Decals............................................................................................................................................................ 2-5
1.2.1 McNeilus Mixer CNG System........................................................................................................................ 2-5
1.2.1 McNeilus Mixer Cross Mount CNG System.................................................................................................. 2-6
1.2.3 Twin Vertical CNG System............................................................................................................................ 2-7
1.3 PRD Vent Locations and Directions.......................................................................................................................... 2-8
1.4 Fire and Explosion Hazards...................................................................................................................................... 2-9
1.4.1 Fire and Explosion......................................................................................................................................... 2-9
1.4.2 Extinguish Media........................................................................................................................................... 2-9
1.4.3 Fire Fighting Instructions............................................................................................................................... 2-9
1.5 Methane Detection/Alarm System (Optional).......................................................................................................... 2-10
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Safety
1.0 Important Safety Information
Take the safety warnings seriously. If you do not understand
them or have questions about them, call McNeilus Truck
and Manufacturing, Inc. at 888-686-7278.
READ AND UNDERSTAND THIS ENTIRE DOCUMENT
BEFORE OPERATING, REPAIRING, OR ADJUSTING
YOUR EQUIPMENT.
DANGER
THOSE WHO USE AND MAINTAIN THIS EQUIPMENT
MUST BE THOROUGHLY TRAINED AND FAMILIAR WITH
THE PRODUCT.
Danger indicates an imminently hazardous
situation which, if not avoided, will result
in death or serious injury. Danger is used
in the most extreme situations.
IF INCORRECTLY USED OR MAINTAINED, THIS
EQUIPMENT CAN CAUSE SEVERE INJURY.
Always keep this manual in a location where it is readily
available for persons who operate or maintain the product.
Additional copies of this manual are available from
McNeilus Truck and Manufacturing, Inc. Please contact
McNeilus Truck and Manufacturing, Inc. at 888-686-7278 if
you require additional manuals or if you have any questions
about the information in this manual, this product, or safe
operating procedures.
WARNING
Warning indicates a potentially hazardous
situation which, if not avoided, could result
in serious injury or death.
CAUTION
THESE SAFETY PROCEDURES ARE FOR YOUR OWN
PROTECTION.
Caution indicates a situation that might
result in property damage.
Do not operate this equipment until you have read its
contents thoroughly. Please contact McNeilus Truck and
Manufacturing, Inc. if you require assistance.
SAFETY NOTICE
Should operators of this equipment have a reading or
learning disability, dyslexia, or other such condition, they
must be assigned a mentor/trainer to read and explain
to them the entire contents of this manual as well as the
safety guidelines, danger, caution, and warning decals on
this unit. Such individuals should not be allowed to operate
this equipment until they thoroughly understand all of these
materials. Failure to do so can result in serious injury or
death.
WARNING
The CNG fuel storage system should be
serviced only in well ventilated areas that
comply with all federal, state, and local
regulations.
Serious personal injury or death may occur.
Safety and safe working procedures must be followed at all
times.
SAFETY NOTICE
Perform your company’s Lockout/Tagout procedure. If
your company does not have a Lockout/Tagout procedure,
follow OSHA 1910.147 and 1910.146 Confined Space as
appropriate.
Perform your company’s Lockout/Tagout
procedure. If your company does not have a
Lockout/Tagout procedure, follow OSHA
1910.147 and 1910.146 Confined Space as
appropriate.
1.1 Safety Notices
Safety notices are one of the primary ways to call your
attention to potential hazards.
WARNING
The operator of this vehicle must be
properly licensed and trained to operate
this vehicle.
THIS SAFETY SYMBOL INDICATES IMPORTANT
SAFETY MESSAGES IN THIS MANUAL.
If you do not have the proper training and
licensing to operate this vehicle, you are
putting yourself and others at risk of
serious injury or death.
WHEN YOU SEE THIS SYMBOL, CAREFULLY READ
THE MESSAGE THAT FOLLOWS.
BE ALERT TO THE POSSIBILITY OF PERSONAL
INJURY OR DEATH.
If you are uncertain how to operate this
vehicle, inform your supervisor or contact
McNeilus Truck and Manufacturing, Inc.
at 888-686-7278.
The following safety notices are used throughout this
manual.
The “signal words” of DANGER, WARNING, and CAUTION
have specific meanings to alert you to the relative level of
hazard.
© 2016 McNeilus Truck and Manufacturing, Inc.
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CNG — Service Manual
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Safety
WARNING
DANGER
2
KEEP THE EQUIPMENT AREA WELL
VENTILATED. CNG is considered to be
non-toxic by inhalation. The effects of
inhalation of high concentrations may
cause the same effects as asphyxiation.
This includes central nervous system
depression such as dizziness, drowsiness,
headache, and similar narcotic symptoms,
but no long-term effects if removed from the
exposure area. Numbness, a “chilly” feeling,
and vomiting have been reported from
accidental exposures to high concentrations.
Wear proper Personal Protective Equipment
(PPE) such as hard hats, safety glasses or
goggles, sturdy gloves, hearing protection,
steel toed boots, and snug fitting sturdy
long-sleeve shirt and long pants when
operating, fueling, defueling, or maintaining
the truck.
Reflective clothing is recommended for
drivers and employees.
Serious personal injury or death can result
without proper PPE.
Failure to follow will cause serious personal
injury or death.
WARNING
Use the three-point contact method (either
two hands and one foot, or two feet and one
hand on the ladder at all times) when
climbing the ladder. Always face the ladder
when climbing up or down. Serious personal
injury may result due to a fall.
DANGER
KEEP THE EQUIPMENT AREA WELL
VENTILATED. Carbon Monoxide poisoning
can occur as a result of poor installation,
poor maintenance or failure or damage to a
gas component in service, gas is not
burned properly, or when cabs are poorly
ventilated and carbon monoxide is unable
to escape.
WARNING
Do not climb on ladders or ride on
platforms (if equipped with either) while the
truck is in motion or when ladders or
platforms are wet and slippery. Serious
personal injury may result due to a fall.
Failure to follow will cause serious personal
injury or death.
WARNING
WARNING
Natural gas is flammable and explosive.
Never use any type of open flame (match,
lighter, or other) as a source of light
around the CNG fuel storage system.
Use proper fall protection equipment and
training when inspecting or maintaining the
CNG cylinder on the truck.
Serious personal injury or death may occur.
Failure to use proper fall protection
equipment may result in serious personal
injury or death.
WARNING
This product may contain materials with
chemicals or byproducts of chemical
processes known in the State of California
to cause cancer or birth defects or other
reproductive harm (California Proposition 65).
WARNING
Safety decals must be replaced anytime
they are damaged, missing, or cannot be
read clearly. Failure to have proper decals
in place can result in serious injury or
death. If you require safety decals, please
contact McNeilus Truck and Manufacturing,
Inc. at 888-686-7278.
WARNING
The CNG fuel system must not be modified
from its original configuration. Modifications
may not comply with safety standards.
Failure to comply may result in serious
personal injury or death.
CNG — Service Manual
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© 2016 McNeilus Truck and Manufacturing, Inc.
Safety
1.2 Safety Decals
The following safety decals are found on the Fuel Control
Module and on the vehicle and warn of hazards related to
the use of this equipment. Read and understand all safety
decals before operating this equipment.
If any safety decals on the equipment are not clearly
readable, contact McNeilus Truck and Manufacturing, Inc.
at 888-686-7278 or www.streetsmartparts.com to order
replacements. Use only McNeilus replacement decals.
2
The locations for the following decals are illustrated on
charts and drawings of the vehicles on the following pages.
1.2.1 McNeilus Mixer CNG System
Ref No.
Part Number
Qty.
Comments
1
1532985
2
2
1479924
2
One decal is placed on the air intake under the front hood.
3
1479921
2
One decal on each CNG tank and one on rear of vehicle.
4
1479922
1
5
1534429
1
6
1479911
2
7
1479915
1
One decal on each side.
NOTE: Only one side of the truck is shown for illustrative purposes.
McNeilus Mixer CNG Mount
5
2
3
4
1
6
3
7
1
2
© 2016 McNeilus Truck and Manufacturing, Inc.
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CNG — Service Manual
Safety
1.2.1 McNeilus Mixer Cross Mount CNG System
2
Ref No.
Part Number
Qty.
Comments
1
1532985
4
One decal on each CNG tank and one on the fuel management module box.*
2
1479924
2
One decal is placed on the air intake under the front hood and one on the fuel management module
box.
3
1479921
4
One decal on each CNG tank and one on rear of vehicle.*
4
1479922
1
5
1534429
1
6
1479911
2
7
1479915
1
One decal on each side.
* The highest CNG capacity systems will have a frame mounted tank on either side of the truck and a single tank cross
mounted on the back of the frame behind the cab. The number of necessary decals is dependent upon system configuration.
NOTE: Only one side of the truck is shown for illustrative purposes.
McNeilus Mixer Cross Mount CNG System
5
1
2
3
1
3
6
4
3
7
1
2
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© 2016 McNeilus Truck and Manufacturing, Inc.
Safety
1.2.3 Twin Vertical CNG System
Ref No.
Part Number
Qty.
Comments
1
1532985
3
One decal on each CNG tank and one on the fuel management module box.
2
1479924
2
One decal placed on the air intake under the front hood (not shown) and one on the fuel management
module box.
3
1479921
3
One decal on each CNG tank and one on rear of vehicle.
4
1479922
1
7
1479915
1
2
3
Twin Vertical Mixer CNG Mount
3
4
1
1
3
7
1
2
© 2016 McNeilus Truck and Manufacturing, Inc.
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CNG — Service Manual
Safety
1.3 PRD Vent Locations and Directions
NOTE: Arrows indicate the direction the natural gas vents from the PRDs.
Twin Vertical Mount
Frame and
Cross Mount
2
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© 2016 McNeilus Truck and Manufacturing, Inc.
Safety
1.4 Fire and Explosion Hazards
1.4.3 Fire Fighting Instructions
Auto Ignition Point: 900 - 1170°F (482 - 632°C)
Natural gas fires should not be extinguished unless flow
of gas can be immediately stopped. Shut off gas source
and allow gas to burn out. If spill or leak has not ignited,
determine if water spray will assist in dispersing gas or
vapor to protect personnel attempting to stop the leak.
Lower Explosive Limit (%): 5
Upper Explosive Limit (%): 15
Use water to cool equipment, surfaces, and containers
exposed to fire and excessive heat. For large fires, the
use of unmanned hose holders or monitor nozzles may be
advantageous to further minimize personnel exposure.
WARNING
Natural gas is flammable and explosive.
Never use any type of open flame (match,
lighter, or other) as a source of light
around the CNG fuel storage system.
If there is a fire, isolate the area. Let the tank burn unless
leak can be stopped. Withdraw immediately in the event
of a rising sound from a venting safety device. Large fires
typically require specially trained personnel and equipment
to isolate and extinguish.
Serious personal injury or death may occur.
WARNING
Fire fighting activities that may result in potential exposure
to high heat, smoke or toxic by-products of combustion
should require NIOSH/MSHA- approved pressure-demand,
self-contained breathing apparatus with full face piece and
full protective clothing.
KEEP THE EQUIPMENT AREA WELL
VENTILATED. Although CNG is non-toxic,
it can cause asphyxiation in a confined area
without ventilation. Any atmosphere that
does not contain enough oxygen for
breathing can cause dizziness,
unconsciousness, or even death. Even
though CNG is sulfurized, the smell may go
unnoticed on some vehicles, such as a
refuse truck. Without adequate ventilation,
natural gas will displace the oxygen and give
no warning that a non-life supporting
atmosphere is present. Store CNG in a well
ventilated area.
Refer to the CNG Material Safety Data Sheet (MSDS) for
more information on natural gas fire and explosion hazards.
Serious personal injury or death may occur.
1.4.1 Fire and Explosion
There is a dangerous fire and explosion hazard when
natural gas is exposed to heat, sparks, or flame. Natural
gas is lighter than air and may travel long distances to a
point of ignition and flash back. Containers containing or
which have contained natural gas may explode in heat or
fire.
1.4.2 Extinguish Media
To extinguish a natural gas fire, stop the flow of natural
gas, use dry chemical, carbon dioxide, halon, or water.
Fire should not be extinguished unless flow of gas can be
immediately stopped.
© 2016 McNeilus Truck and Manufacturing, Inc.
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CNG — Service Manual
2
Safety
1.5 Methane Detection/Alarm System
(Optional)
2
NOTE
If methane detector/alarm is used, note the
information below.
The methane vapor detection system utilizes two sensors
to identify methane vapors: one located in the cab
compartment and one located in the engine compartment
of the vehicle. The system operates with both a visual and
an audible alarm to warn the operator of potential danger.
The alarms are triggered at trace levels (20% LEL [Lower
Explosive Limit]) and at significant levels (50% LEL) of
vapor concentration. An internal relay controls two indicator
lights (one green and one red) that can be seen through
the windshield. The lights should always be checked before
entering the vehicle. The green light will go out and the
red light will illuminate 15 seconds after a significant level
of methane has been detected. The methane detector
also has a press-to-test button that can be used to test the
indicator lights and the audible alarm.
When the vehicle battery is disconnected, the
methane detector/alarm system will not
operate therefore the green light will not be
on.
The methane detector/system is powered
by the vehicle battery and is active at all
times unless the vehicle battery is
disconnected or the fuse is blown.
Hand-held methane detector/ alarm devices
should be used when working on natural gas
vehicles with a nonfunctional or
disconnected methane detector/alarm
system and where no auxiliary methane
detector/alarm system is installed.
WARNING
If the optional methane detection system is used,
when approaching the vehicle to enter, do not
open the vehicle if the RED LIGHT IS ON!
Do not open the vehicle doors if the ALARM IS
SOUNDING!
Do not open the vehicle doors if the GREEN
LIGHT is NOT ON!
If the indicator light is red, if the alarm is
sounding or if the green light is NOT ON, it is
unsafe to open the vehicle doors because even
static electricity can ignite concentrated methane
fumes in an enclosed area.
Immediately implement the following procedure:
Remove all personnel from the area. Turn off
electrical circuits and sources of ignition in the
immediate area. Manually turn off the Fuel
Shut-Off Valve on each fuel tank to prevent
further gas leakage. Wait until the gas has
dissipated and the alarm situation has been
cleared. It is now safe to open the vehicle doors
and windows to vent the vehicle. Do not operate
the vehicle until the source of the leak has been
repaired.
WARNING
In the event of an alarm while operating the
vehicle, immediately open the cab windows,
safely stop the vehicle, shut down the
engine, and turn off the ignition. Exit the cab
and leave the doors and windows open to
vent the vehicle. Manually turn off the Fuel
Shut-Off Valve on each fuel tank to prevent
further gas leakage. Wait until the gas has
dissipated and the alarm situation has
cleared. Do not operate the vehicle until the
source of the leak has been repaired.
Methane is extremely flammable. Inhalation
may cause dizziness, drowsiness, headache,
but no long-term effects if removed from the
exposure area. Serious personal injury or
death may occur.
1
Methane is extremely flammable. Serious
personal injury or death may occur.
2
4
Gas Detection System
AMGaDS III PLUS
3
POWER
Push
To
Silence
Silence
Engaged
Shutdown
Reset
Relay
Engaged
Gas Concentration
SIGNIFICANT
5
6
Trace
1
2
NE
NE
ZO
ZO
SENSOR FAULT
AMGaDS III
9
Push to Test
8
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© 2016 McNeilus Truck and Manufacturing, Inc.
7
Safety
Methane Detection System
Number
Description
Function
Power On Indicator (Green)
The green LED should always be on when there is no methane
detection. No power on/off switch is provided for this unit as it should be
on at all times.
Significant Alarm Indicators (Red)
Illumination of the red LED for “Zone 1” (cab compartment) or “Zone 2”
(engine compartment) indicates the system has detected gas fumes in
concentrations above 50% of the Lower Explosive Limit (LEL) and an
audible horn will sound.
3
Trace Sensor Alarm Indicators
(Amber)
Illumination of the amber LED for “Zone 1” (cab compartment) or “Zone
2” (engine compartment) indicates the system has detected a gas
concentration above 20% of the LEL. This is a cautionary situation.
Corrective measures should be taken as soon as possible — including
opening the vehicle windows and returning the vehicle for service — to
identify and correct the source of the methane leak.
4
Audible Alarm Silence Button
Press to silence the audible alarm.
5
Alarm Silenced Indicator
Illuminates to indicate the audible alarm has been silenced.
6
Relay On/Off Indicator
If there is a SIGNIFICANT alarm detected for 15 seconds, the “Relay
Engaged” LED will go on. The windshield-visible green light will go out
and the windshield-visible red light will illuminate.
7
Relay Reset Button
Only after the methane gas has cleared and the alarms are off, the
internal relay can be reset by pressing the “Shutdown Reset” button.
After pressing this button, the “Relay Engaged” LED will go off.
8
System Test Button
Press this button to perform a self-test of all electrical and sensor
functions and simulate an alarm condition. The system returns to normal
when the test button is released.
Sensor Fault Indicators
If either Sensor Fault Light remains illuminated or go on intermittently,
a disconnected or faulty sensor is indicated in the corresponding
zone. Zone 1 is the cab compartment sensor and Zone 2 is the engine
compartment sensor. Do not operate the vehicle until a qualified person
corrects this condition
1
2
9
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CNG System 3
Table of Contents
1.0 CNG SYSTEM.................................................................................................................................................................... 3-3
1.1 Fuel Control Module Components............................................................................................................................. 3-3
1.1.1 High Pressure Gauge.................................................................................................................................... 3-3
1.1.1.1 High Pressure Line Identification Tags........................................................................................... 3-3
1.1.2 Low Pressure Gauge..................................................................................................................................... 3-3
1.1.3 Manual Shut-Off Valve................................................................................................................................... 3-3
1.1.4 Purge Valve................................................................................................................................................... 3-4
1.1.5 Coalescing Filter............................................................................................................................................ 3-4
1.1.6 Pressure Regulator....................................................................................................................................... 3-4
1.1.7 Pressure Sensor............................................................................................................................................ 3-4
1.1.8 Fueling Receptacle........................................................................................................................................ 3-4
1.1.9 Remote Fueling Receptacle.......................................................................................................................... 3-5
1.2 Fuel Storage Pod...................................................................................................................................................... 3-5
1.2.1 Pressure Relief Devices (PRD)..................................................................................................................... 3-5
1.2.2 Tank Manual Fuel Shut-Off Valves................................................................................................................ 3-5
1.3 Vehicle Fueling.......................................................................................................................................................... 3-5
1.3.1 Vehicle Fueling.............................................................................................................................................. 3-6
1.3.2 Vehicle Fueling Through Remote Receptacles............................................................................................. 3-6
1.3.3 Filling Standards............................................................................................................................................ 3-7
1.3.4 Overpressuring Standards............................................................................................................................ 3-7
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CNG System
1.0 CNG System
1.1.2 Low Pressure Gauge
• Fuel Control Module
The low pressure gauge, located in the front panel of the
fuel control module, indicates the fuel pressure exiting the
regulator and being supplied to the vehicle’s engine. A
typical reading for this gauge is between 100 psi and 120
psi.
• Fuel Storage Pods
1.1.3 Manual Shut-Off Valve
• Plumbing
The manual shut-off valve is located on the front of the fuel
control module. When the valve is in the vertical position
(arrow pointing down), fuel is prohibited from flowing from
the fuel tanks to the vehicle’s engine.
The service pressure of this CNG system is 3,600 psig (250
bar).
The CNG fuel system has several components
1.1 Fuel Control Module Components
The fuel control module has several functions (these
functions are described in sections 1.1.1-1.1.9):
MA10 CNG Control Module Manual Shut-Off Valve
• Local and remote storage tank pressure measurement
• Manual and ignition controlled shut-off
• Pressure reduction from storage tank pressure to
engine supply pressure
2000
1000
• Filtration of fuel stream
3000
4000
5000
6000
• Liquid removal from fuel stream
1.1.1 High Pressure Gauge
The high pressure gauge, located in the front panel of
the fuel control module, indicates the fuel pressure being
supplied to the regulator. This gauge will indicate fuel tank
pressure if the manual shut-off valve is open and all other
valves between the fuel module and the fuel tanks are also
open.
1.1.1.1 High Pressure Line Identification Tags
High pressure lines have high pressure line identification
tags placed every 24 inches on lines that are longer than 30
inches. Look for the tags before performing maintenance on
or near high pressure lines.
© 2016 McNeilus Truck and Manufacturing, Inc.
MA20 CNG Control Module with Defueling Manual
Shut-Off Valve
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CNG System
1.1.4 Purge Valve
1.1.8 Fueling Receptacle
The purge valve, located inside the service access door,
safely purges all CNG fuel from the fuel control module in
order to safely access the filter housing.
The fueling receptacle, located on the front panel of the
fuel control module, is used for adding fuel to the vehicle’s
fuel tanks. Standard equipment is a buzzer in the cab that
signals when the fuel control module is open. An optional
part is a door interlock that requires the door be closed for
the vehicle’s ignition circuit to start the engine.
1.1.5 Coalescing Filter
The coalescing filter, located inside the service access door,
removes solid particles as well as liquids (such as water or
oil in aerosol form). The filter requires periodic maintenance
to remove accumulated liquids.
Purge Valve
MA10 CNG Control Module Fuel Receptacle
Coalescing Filter
2000
1000
3000
4000
5000
NGV 1
Standard
Fueling Port
6000
3
MA11 CNG Control Module with Defueling
Receptacle
1.1.6 Pressure Regulator
Defueling Port
The pressure regulator, located inside the service access
door, converts high pressure fuel supplied from fuel tanks
to a low pressure that is needed for proper operation of
the vehicle’s engine. The regulator also contains a shut-off
valve that, through the ignition circuit, can allow or prohibit
the flow of fuel to the engine.
NGV 1 Port
1.1.7 Pressure Sensor
The pressure sensor, mounted in the regulator’s sensor
port inside the service access door, generates an electrical
signal that is proportional to the pressure being supplied to
the regulator from the fuel tanks. The signal indicates the
fuel level on the fuel gauge.
CNG — Service Manual
Transit Fill
3-4
© 2016 McNeilus Truck and Manufacturing, Inc.
CNG System
1.2 Fuel Storage Pod
MA20 CNG Control Module with Defueling
Receptacle
The fuel storage pod houses and protects the fuel tanks
and their associated hardware.
Defueling Port
1.2.1 Pressure Relief Devices (PRD)
A thermally activated device installed in direct contact
with internal pressure in each tank that will release the
contained gas in excess temperature (219° F).
NGV 1 Port
1.2.2 Tank Manual Fuel Shut-Off Valves
The quantity per fuel pod will be dependent upon total
capacity per system. There will be one manual shut-off
per tank. The shut-off valves turn off fuel flow from the
tank to the fuel control module for plumbing or component
maintenance and service. They do not isolate the tank from
the PRD plumbing.
Transit Fill
MA20 CNG Control Module with Defueling
Receptacle (no Transit Fill Port)
Defueling Port
NGV 1 Port
1.1.9 Remote Fueling Receptacle
Some vehicles may be equipped with additional remote fill
receptacles located at the front bumper or on the passenger
side of the vehicle.
© 2016 McNeilus Truck and Manufacturing, Inc.
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CNG System
1.3 Vehicle Fueling
1.3.1 Vehicle Fueling
A vehicle fueled through the fuel receptacle on the front
panel of the fuel control module has two (2) check valves to
protect against uncontrolled flow of fuel out of the storage
tanks. The first check valve is within the fuel receptacle, and
the second check valve is inside the fuel control module
and is used in the event the fuel receptacle is damaged.
1.3.2 Vehicle Fueling Through Remote
Receptacles
UNIVERSAL FILL TABLE FOR NGV FUEL CONTAINERS
CNG TEMPERATURE, °F
3
Fuel flows from remote fill receptacles through the fuel
control module to storage tanks. A double check valve
arrangement is also used in this process.
200
190
180
170
160
150
140
130
120
110
100
90
80
70
60
50
40
30
20
10
0
-10
-20
-30
-40
-50
OverFill
120%
110%
100%
90%
80%
70%
4500psig, 84°F
60%
50%
40%
30%
20%
15%
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
CONTAINER PRESSURE, PSIG
Gas Data Source: A.G.A. Report No. 8, Catalog No. XQ 9212) and a typical natural gas composition (93.6% methane, 3.1% ethane,
1.4% nitrogen, 0.8% carbon dioxide, plus other heavier hydrocarbons.
1
Table 1
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© 2016 McNeilus Truck and Manufacturing, Inc.
CNG System
1.3.3 Filling Standards
According to ANSI NGV 2-2007 standards, CNG tanks are
designed to be filled to a pressure that does not exceed any
of the following conditions:
a. A pressure that would settle to 1.0 times the service
pressure at a settled temperature of 70°F (21°C).
b. A settled pressure of 1.25 times the service pressure at
135°F (47°C); or
c. 1.25 times the service pressure immediately after filling,
regardless of temperature.
The designed service pressure and temperature of
your CNG tank is 3,600 psig at 70°F, with a maximum
working condition of 4,500 psig at or below 135°F.
3
1.3.4 Overpressuring Standards
According to ANSI NVG 2-2007 standards, any tank that
has exceeded the limits of the constraints listed above shall
be handled accordingly.
Any tank that is believed to have a pressure greater
than 1.25 times service pressure shall be defueled,
depressurized, and removed from service.
The tank shall then be inspected by an agency authorized
by the manufacturer..., the tank may be returned to service
if it is determined that the tank has not suffered any
damage that may reduce its service life. A record of such
incident shall be sent to and retained by the manufacturer.
If you feel the tank has been over pressurized, i.e. above
4,500 psig, contact McNeilus Truck and Manufacturing,
Inc. at 888-686-7278 for approved authorized agencies to
inspect the tank.
Should you find an overpressure situation and a need to
defuel, reference the Fueling and Defueling section of this
manual for proper defueling procedures.
If the tank is found to be damaged beyond use, contact
McNeilus Truck and Manufacturing, Inc. at 888-6867278 for proper disposal procedures. See the Preventive
Maintenance section of this manual for end of service life
procedures if tank has been over pressurized.
© 2016 McNeilus Truck and Manufacturing, Inc.
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CNG Fueling and Defueling
Table of Contents
1.0 OPERATION....................................................................................................................................................................... 4-3
1.1 Warm Up Procedure.................................................................................................................................................. 4-3
2.0 FUELING PROCEDURE.................................................................................................................................................... 4-3
3.0 DEFUELING THE CNG TANKS PROCEDURE................................................................................................................. 4-3
3.1 Defueling Requirements............................................................................................................................................ 4-3
3.2 Grounding Information............................................................................................................................................... 4-4
3.3 Identify Your Fuel Management Module Box............................................................................................................. 4-4
3.3.1 Install a Defueling Three-Way Valve to the Fuel Box (MA10 Only)............................................................... 4-5
3.4 Receptacle Defueling Procedure Set-Up.................................................................................................................. 4-5
3.4.1.1 Option 1: Defueling with a Defueling Panel (Atmospheric Venting)............................................... 4-5
3.4.1.2 Option 2: Defueling with a Defueling Panel (Compressor Inlet Method)....................................... 4-5
3.4.1.3 Option 3: Defueling with a Defueling Panel (Vent Back to Gas Main Method).............................. 4-5
3.5 Vehicle to Vehicle Defueling Procedure Set-Up........................................................................................................ 4-5
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Fueling and Defueling
1.0 Operation
8.
Return dispensing nozzle to appropriate location on
dispenser.
1.1 Warm Up Procedure
9.
Return dust cap to vehicle fuel receptacle.
Run the vehicle for 15 minutes at low throttle before starting
the day’s route or until coolant reaches minimum chassis
operating temperature and adequately warm the CNG
regulator to prevent freeze up.
10. Disengage the parking brake.
2.0 Fueling Procedure
All CNG tanks in the CNG system must be depleted of all
fuel before replacing the PRD valve(s).
1.
Make sure the vehicle’s engine is turned off.
2.
Set the parking brake.
3.
Access the fuel receptacle and remove dust cap.
4.
Retrieve fueling nozzle from dispenser.
5.
Turn the control handle 1/4 turn counterclockwise and
attach CNG dispensing nozzle to vehicle receptacle.
3.0 Defueling the CNG Tanks
Procedure
WARNING
The defueling process must occur outside,
away from flammable materials.
Failure to comply could result in an
explosion and serious personal injury or
death.
There are multiple methods to defuel the CNG tanks in the
CNG system. Choose the method that is appropriate for
the equipment you have. Read the entire Procedure before
beginning.
3.1 Defueling Requirements
The most important information with defueling is ensuring
the technician’s safety which requires training and careful
attention to using proper procedures. Defueling is not
something technicians should “figure out” when it is time to
perform it, but requires significant preparation. Every facility
that services CNG vehicles should prepare for defueling
ahead of time, especially in case emergency defueling
becomes necessary.
Figure 1: Attach dispensing nozzle to vehicle.
6.
Turn the control handle 1/2 rotation clockwise to lock
the nozzle to the vehicle receptacle. The vehicle is
ready for fueling.
WARNING
Basic Rules for Defueling
• Deplete as much fuel as possible prior to
defueling
• Notify appropriate nearby personnel prior
to defueling
• Always ground (earth ground) the vehicle
and the fuel system being defueled
Figure 2: Turn control handle to lock the
nozzle to the vehicle receptacle.
7.
After dispensing is complete, turn control handle on
nozzle 1/2 turn counterclockwise and remove CNG
dispensing nozzle from vehicle receptacle.
• Never defuel indoors
• Always defuel in a well-ventilated area
(outside)
• Always wear personal protective
equipment such as safety glasses, gloves,
safety shoes, hard hats
• Be familiar with evacuation routes
Failure to comply could result in serious
personal injury or death.
Figure 3: Remove the dispensing nozzle from the vehicle
receptacle.
© 2016 McNeilus Truck and Manufacturing, Inc.
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Fueling and Defueling
3.3 Identify Your Fuel Management
Module Box
WARNING
Even if the truck has stalled after running it
out of fuel, and you think all fuel has been
depleted, check the high pressure gauge to
make sure it is at zero.
If the gauge is not at zero, continue to
deplete the fuel until the gauge reads zero.
Failure to comply may result in serious
personal injury or death.
1.
4
There are three types of CNG fuel management module
boxes. Identify which type you have and follow the
appropriate procedures for defueling.
If you have MA10, install the three-way valve before
beginning to defuel. See 3.3.1 Install a Defueling ThreeWay Valve to the Fuel Box (MA10 Only). If you have MA11
or MA20, go to 3.4 Receptacle Defueling Procedure SetUp.
Close the manual shut-off valve on each storage vessel
or close the electronically activated solenoid valves (if
available) on the fuel delivery and storage system. On
vehicles with electronically activated valves, use the
manual lock-down screw or remove the relay or fuse/
circuit breaker in the circuit.
2.
Run the vehicle on CNG until it stalls.
3.
Attempt to start the vehicle again. If it starts, let it run
until it stalls again. Repeat the step until the vehicle no
longer starts.
2000
1000
3000
4000
5000
6000
Fueling
Receptacle
3.2 Grounding Information
Before choosing one of the following options, ground the
truck.
WARNING
MA10
The tank must be grounded before venting.
The venting orifice must be grounded with a
3-gauge wire minimum to an appropriate
ground source at least eight (8) feet (2.44
meters) in the ground.
Failure to comply may result in serious
personal injury or death.
Defueling
Valve
Fueling
Receptacle
MA11 or MA20
Figure 4: Illustration of a grounding
rod in the ground.
CNG — Service Manual
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© 2016 McNeilus Truck and Manufacturing, Inc.
Fueling and Defueling
3.3.1 Install a Defueling Three-Way Valve to the
Fuel Box (MA10 Only)
1.
Close the manual shut-off valve on each storage vessel
or close the electronically activated solenoid valves (if
available) on the fuel delivery and storage system. On
vehicles with electronically activated valves, use the
manual lock-down screw or remove the relay or fuse/
circuit breaker in the circuit.
2.
Run the vehicle on CNG until it stalls.
3.
Attempt to start the vehicle again. If it starts, let it run
until it stalls again. Repeat the step until the vehicle no
longer starts.
4.
Check the high pressure gauge to make sure it reads
zero. If it does not read zero, repeat Step 3 (above)
until both the high pressure gauge reads zero and the
truck no longer starts.
5.
Once pressure is removed from lines, install the 3-way
valve at the back of the fuel module or in-line wherever
accessible.
6.
Once installed, ensure the 3-way valve is in the OFF
position, then slowly open the tank manual valves.
7.
Continue to Defueling Options (below).
3.4.1.2 Option 2: Defueling with a Defueling
Panel (Compressor Inlet Method)
By far the easiest method, this procedure requires preplanning and special equipment installed at the CNG fueling
station. If there is not a fueling station at the site where the
technician is working on the vehicle, it is required to tow
the vehicle to the facility to repair after defueling. In this
method, the vehicle is connected through the defueling
nozzle to the defueling panel and the compressor at the
fueling station extracts the gas from the vehicle. The vehicle
and its fuel system must be grounded.
If you have a MA10 Fuel Box system, remove the defueling
3-way valve.
3.4.1.3 Option 3: Defueling with a Defueling
Panel (Vent Back to Gas Main Method)
The least common method, venting back to gas main,
requires pre-planning and specialized equipment. The local
gas utility would install special valving, regulation, and
piping that allows the gas to be put back into the distribution
system. This process works on the basis of pressure
equalization between the vehicle and the utility system, so
it is possible that there will still be pressure in the vehicle’s
onboard fuel system. As in the other defueling methods,
both the vehicle and the fuel system must be grounded
during the process.
Choose one of the following options:
If you have a MA10 Fuel Box system, remove the defueling
3-way valve.
Option 1: Run truck as low on fuel as possible. Once
the fuel level has been depleted as much as possible,
remaining fuel shall be depleted during defueling.
Defueling ThreeWay Valve
OR
Option 2: Use vehicle to vehicle defueling to reduce
pressure as far as possible (see Vehicle to Vehicle
Defueling Procedure Set-Up).
Defueling
Connection
CNG Fuel Fill
Connection
3.4 Receptacle Defueling Procedure SetUp
Once the vehicle is equipped with the defueling receptacle,
there must be an approved place to put the natural gas fuel
removed from the vehicle. The following are the three most
common defueling options.
3.5 Vehicle to Vehicle Defueling
Procedure Set-Up
3.4.1.1 Option 1: Defueling with a Defueling
Panel (Atmospheric Venting)
Defueling Hose for Vehicle to Vehicle Defueling
The first thing to check when using this method is your
local air quality regulations. There may be local air quality
regulations regarding the release of methane into the
atmosphere. If atmospheric venting is acceptable in
the area, then a vent stack apparatus that meets the
requirements established in either the Uniform Building
Code or the International Building Code must be followed.
The local authority having jurisdiction—typically the Fire
Marshal—should be consulted. Both the vehicle and the
fuel system must be grounded (see Grounding Information).
If you use this method, you must fill out the CNG Fuel
Release Tracking Sheet attached to this bulletin and return
it to the e-mail address listed on it.
A defueling hose is used to transfer CNG fuel from a
supplying (defueling) vehicle to a receiving (fueling) vehicle.
There are two different length defueling hoses available
from McNeilus Truck and Manufacturing, Inc.
20 foot defueling hose is part number 1462077
50 foot defueling hose is part number 1464662
If you have a MA10 Fuel Box system, remove the defueling
3-way valve.
© 2016 McNeilus Truck and Manufacturing, Inc.
4-5
1.
A defueling hose can be used only if one of the
vehicles is equipped with a defueling receptacle. The
supplying vehicle must have the defueling valve.
2.
In order for the CNG fuel to flow, the tank pressure
in the supplying vehicle must be higher than the tank
pressure in the receiving vehicle.
CNG — Service Manual
4
Fueling and Defueling
3.
Open access doors on the fuel control module on both
vehicles.
4.
Before connecting the defueling hose to either vehicle,
open the purge valve on the defueling hose to release
any pressure that may be in the hose. Close the purge
valve after pressure is released.
5.
Turn the defueling control valve to the Normal
Operation position to release pressure in the
defueling circuit. This also allows the hose’s defueling
nozzle to be connected to the defueling receptacle. It is
not possible to make the connection if the valve is not
in the Normal Operation position.
6.
Connect the hose’s defueling nozzle to the defueling
receptacle of the supplying vehicle (Figure 7) by pulling
back on the quick connect collar on the hose and
pushing it onto the vehicle’s coupler.
4
Defueling Hose
Defueling
Receptacle
Figure 5Figure 7: Defueling hose attached to
defueling receptacle on supplying vehicle.
7.
Connect the hose’s fueling nozzle to the fueling
(NGV1) receptacle on the receiving vehicle.
8.
Slowly turn the defueling control valve on the supplying
vehicle to Defueling Enabled to initiate the flow of
CNG fuel from the supplying vehicle to the receiving
vehicle.
9.
Adjust this flow to a steady flow rate. Too fast of a flow
rate will cause the system to freeze up.
10. When fuel stops flowing, check the gas pressure by
reading the high pressure gauges of both vehicles.
Both CNG tank pressure gauges should equalize.
11. Stop the flow of CNG fuel by turning the defueling
control valve to the Normal Operation position.
NOTE: Pressure in the defueling hose is vented so
that the hose can be disconnected.
12. Disconnect the fuel hose from the supplying vehicle by
pulling back on the quick connect collar on the hose
and pulling the hose away from the vehicle’s coupler.
CNG — Service Manual
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© 2016 McNeilus Truck and Manufacturing, Inc.
Preventive Maintenance
Table of Contents
1.0 CNG INSPECTION............................................................................................................................................................ 5-3
1.1 CNG System Inspection............................................................................................................................................ 5-3
1.2 General Visual Inspection.......................................................................................................................................... 5-3
1.3 Detailed Visual Inspection......................................................................................................................................... 5-3
1.4 Fitting Leak Inspection.............................................................................................................................................. 5-3
1.5 Mounting Bracket Inspection..................................................................................................................................... 5-3
1.6 End of Service Life of a Tank..................................................................................................................................... 5-3
1.6.1 Condemned Tank Tool List............................................................................................................................ 5-4
2.0 PREVENTIVE MAINTENANCE......................................................................................................................................... 5-4
2.1 Before Performing Maintenance................................................................................................................................ 5-4
2.1.1 Depressurize Before Working on the Engine Fuel System........................................................................... 5-4
2.1.2 Depressurize Before Working on the Tanks or PRD Plumbing..................................................................... 5-4
2.2 Maintenance Schedule.............................................................................................................................................. 5-5
2.2.1 Daily CNG Fuel System Checks................................................................................................................... 5-5
2.2.1.1 Check for CNG Leaks.................................................................................................................... 5-5
2.2.2 Maintenance Chart........................................................................................................................................ 5-5
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Preventive Maintenance
1.0 CNG Inspection
1.3 Detailed Visual Inspection
A detailed visual inspection is conducted by trained
personnel holding the proper certifications and thoroughly
inspects and evaluates the tank and bracket assembly.
McNeilus Truck and Manufacturing, Inc. employs CNG
inspectors who are certified by CSA International to recertify
tanks. Contact McNeilus Truck and Manufacturing, Inc. at
888-686-7278. All covers and shields must be removed to
enable the inspector to see the tanks.
1.1 CNG System Inspection
The CNG system shall have a detailed visual inspection
after a fire or motor vehicle accident or when the vehicle
has been in a collision operating at over five (5) mph and at
least every 36 months or 36,000 miles, whichever comes
first, for damage and deterioration. The CNG system must
be recertified by a CNG inspector who is certified by CSA
International before the unit is placed back into operation.
McNeilus Truck and Manufacturing, Inc. employs CNG
inspectors who are certified by CSA International to recertify
tanks. Contact McNeilus Truck and Manufacturing, Inc. at
888-686-7278.
The system shall be inspected:
• Prior to installation
• Prior to being filled if there is reason for concern (i.e., if
the vehicle was involved in a collision or fire regardless
if there was contact with the CNG system)
The CNG tanks and fittings must be cleaned before
inspection.
1.
Use warm, soapy water, a mop, and a soft bristle brush
to clean the tanks, tubes, and fittings.
2.
Rinse the components well with clean water.
• Periodically, as required by law, regulation, and/or the
tank design specifications
• When known or suspected to have been abused in
service, such as involvement in fire, impact, exposed to
excessive heat or any other potential damage causing
situation
NOTE: A garden hose works well to wet and rinse off the
area.
• If any unusual behavior is observed, such as emission
of natural gas odor, unexpected loss of gas pressure,
rattling or other indications of looseness, or unusual
snapping or hissing sounds
SAFETY NOTICE
Cylinders that have been involved in an
accident which may have the potential of
Level 2 or Level 3 damage should be
depressurized prior to inspection. See
cylinder manufacturer guidelines for
damage disposition and level descriptions.
1.4 Fitting Leak Inspection
Fittings and connections should be checked for leaks
periodically. Servicing and inspecting for leaks is to be
conducted by individuals with the proper certifications and
training.
1.5 Mounting Bracket Inspection
WARNING
• The tank must be mounted in a manner that adequately
restrains it, but does not induce damage. Because the
tank expands and contracts as the internal pressure
increases or decreases, the tank’s diameter and length
will vary
Use proper fall protection equipment and
training when inspecting or maintaining the
CNG cylinder on the truck.
Failure to use proper fall protection
equipment may result in serious personal
injury or death.
• Verify the tanks are firmly restrained. If a tank is loose
within the brackets, the tank must be vented and
removed from the vehicle, and a visual inspection of
the tank and brackets must be initiated and recorded
1.2 General Visual Inspection
• Verify the bolts, which secure the brackets to the
vehicle, are present and tight
General visual inspection is a general inspection and
evaluation of the visible areas of the system for signs of
gross external damage or abuse. This type of inspection
can be conducted by operators or maintenance personnel.
A general visual inspection is looking for cuts, gouges,
abrasions, discoloration, broken fibers, loose brackets,
damaged gaskets or o-rings, and heat damage. In addition,
verify that all safety signs are still present, readable, and
in good condition. If the truck requires new safety signs,
contact McNeilus Truck and Manufacturing, Inc. at 888-6867278.
• Verify the brackets are in good condition and suitable
for continued service
1.6 End of Service Life of a Tank
Refer to the label marking the end of the manufacturer’s
recommended service life for the tank.
1.
• It is inspected
• Removed from service
This inspection should be a part of normal maintenance or
a scheduled maintenance activity. It should be performed
any time the vehicle is on a service lift or scheduled into the
maintenance shop.
© 2016 McNeilus Truck and Manufacturing, Inc.
When the tank reaches the manufacturer’s
recommended service life,
• Condemned and clearly labeled “CONDEMNED”
at the time of inspection. The marking shall be
affixed to the manufacturer’s label and the duplicate
manufacturer’s label, if used.
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Preventive Maintenance
2.
The tank must be depressurized. Follow all
depressurizing instructions.
2.0 Preventive Maintenance
3.
The tank must be defueled according to proper
defueling procedures.
2.1 Before Performing Maintenance
4.
Flush residual fumes with compressed nitrogen. If
compressed nitrogen is not available, flushing the tank
with water is acceptable. Wait eight (8) hours before
proceeding to the next step.
5.
2.1.1 Depressurize Before Working on the
Engine Fuel System
Before servicing the CNG engine fuel system, remove
pressure from the fuel lines by turning the valves on each
tank to the OFF position. This will stop more fuel from
entering the lines to the engine. Run the engine until it
“dies.” Attempt to start the vehicle again. If it starts, let it
run until it stalls again. Repeat the step until the vehicle no
longer starts. See Depressurizing the CNG Fuel System in
this manual for more information.
The tank must be destroyed by drilling two or more
holes one-half inch or greater in diameter completely
through the tank wall and internal liner in order to
prevent unauthorized pressurization.
1.6.1 Condemned Tank Tool List
• Compressed nitrogen supply to remove as much
natural gas as possible. If nitrogen is not available,
then flush the tank with water
2.1.2 Depressurize Before Working on the Tanks
or PRD Plumbing
Fuel tanks and the lines that connect them must be
depressurized and all fuel removed before any maintenance
on these items is performed. Never bleed the tanks in an
enclosed area. See Depressurizing the CNG Fuel System
in this manual for more information.
• Drill with 1/2 inch (13 mm) bit
CAUTION
5
Residual natural gas and/or air can be
trapped between the liner and the composite
after venting. Allow the vented tank (open to
atmosphere) to sit for 8 hours to allow the
trapped gas to escape before drilling the
condemned tank.
Failure to vent may cause personal injury or
equipment damage.
WARNING
Never purge the tanks in an enclosed area.
Be sure there are no sources of ignition in
the area.
Failure to comply may result in serious
personal injury or death.
NOTE
WARNING
The tank will contain residual gas fumes
after depressurization. Precautions should
be taken to ensure that residual fumes are
not ignited during destruction. Vent all
pressure from the tank and displace residual
fumes with compressed nitrogen. If
compressed nitrogen is not available,
flushing the tank with water will also
displace residual fumes.
CNG — Service Manual
PRD lines are always pressurized. The tanks
the lines are connected to must be
completely depressurized prior to working
on this plumbing.
Failure to completely depressurize the lines
may result in serious personal injury or
death.
5-4
© 2016 McNeilus Truck and Manufacturing, Inc.
Preventive Maintenance
2.2 Maintenance Schedule
2.2.1 Daily CNG Fuel System Checks
2.2.1.1 Check for CNG Leaks
The CNG system is pressurized. During daily inspection,
check for any leaks or damage to the fuel system. The
appearance of frost around a fitting, hose, or tube, a sulfur
smell, or any audible hissing noise may indicate a CNG
leak.
WARNING
Do not operate a vehicle that has a CNG leak.
Failure to comply may result in serious
personal injury or death.
2.2.2 Maintenance Chart
Part
Maintenance
Fuel Filter Housing
Drain filter housing weekly at initial install. If no oil is detected for 2 consecutive weeks, extend
draining process to monthly.
Fuel Filter Element
Replace every six (6) months or when oil is detected in four (4) drains in a row, whichever comes
first.
Fuel Fittings and
Connections
Fittings and connections should be checked for leaks periodically. Servicing and inspecting for
leaks must be conducted by individuals with the proper certifications and training.
Fuel Tank Inspection
Tanks must to be inspected by trained individuals holding the proper certifications.
Tanks must to be inspected:
•
Every 36 months or 36,000 miles, whichever comes first
•
Prior to installation
•
Prior to being filled if there is reason to believe they may have been damaged (i.e., if the
vehicle was involved in an accident, fire)
•
Periodically, as required by law, regulation, and/or the tank design specifications
•
When known or suspected to have been abused in service, such as involvement in fire,
impact, exposed to excessive heat or any other potential damage causing situation
•
If any unusual behavior is observed, such as emission of natural gas odor, unexpected loss of
gas pressure, unusual noises (i.e., rattling, snapping, hissing)
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CNG Component Remove and Replace
Table of Contents
1.0 OVERVIEW.................................................................................................................................................... 6-3
2.0 TORQUE STANDARDS................................................................................................................................. 6-3
3.0 DEPRESSURIZING THE CNG FUEL SYSTEM............................................................................................ 6-3
4.0 REMOVE AND REPLACE FUEL MODULE................................................................................................... 6-4
4.1 CNG Depressurization.............................................................................................................................................. 6-4
4.2 Fuel Module Removal............................................................................................................................................... 6-5
4.3 Fuel Module Upper and Lower Covers...................................................................................................................... 6-7
4.3.1 Upper Cover Removal and Installation.......................................................................................................... 6-7
4.3.2 Lower Cover Removal and Installation.......................................................................................................... 6-7
4.4 Fuel Module Installation............................................................................................................................................ 6-8
4.5 Leak Detection.......................................................................................................................................................... 6-8
5.0 CONNECTING THE FUEL MODULE DOOR INTERLOCK........................................................................... 6-9
5.1 Vehicle Preparation................................................................................................................................................... 6-9
5.2 Door Interlock Installation.......................................................................................................................................... 6-9
6.0 REMOVE AND REPLACE FILL RECEPTACLES........................................................................................ 6-10
6.1 CNG Depressurization............................................................................................................................................ 6-10
6.2 Receptacle Removal and Replacement...................................................................................................................6-11
7.0 REMOVE AND REPLACE LOW PRESSURE SOLENOID ASSEMBLY.......................................................6-11
7.1 CNG Depressurization............................................................................................................................................ 6-12
7.2 Low Pressure Solenoid Assembly Removal and Replacement............................................................................... 6-12
8.0 REMOVE AND REPLACE SOLENOID COIL............................................................................................... 6-14
8.1 Vehicle Preparation................................................................................................................................................. 6-14
8.2 Solenoid Coil Removal and Replacement............................................................................................................... 6-14
9.0 REMOVE AND REPLACE TRANSDUCER.................................................................................................. 6-15
9.1 CNG Depressurization............................................................................................................................................ 6-15
9.2 Transducer Removal and Replacement.................................................................................................................. 6-15
10.0 REMOVE AND REPLACE SIGNAL CONDITIONER................................................................................. 6-16
10.1 Vehicle Preparation............................................................................................................................................... 6-16
10.2 Signal Conditioner Removal and Replacement..................................................................................................... 6-16
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Component Remove and Replace
11.0 REMOVE AND REPLACE FUEL REGULATOR......................................................................................... 6-18
11.1 CNG Depressurization........................................................................................................................................... 6-18
11.2 Fuel Regulator Removal and Replacement........................................................................................................... 6-18
12.0 REMOVE AND REPLACE FUEL FILTER.................................................................................................. 6-24
12.1 Fuel Filter Access Procedure................................................................................................................................ 6-24
12.2 Fuel Filter Drain Procedure................................................................................................................................... 6-24
12.3 Fuel Filter Element Replacement Procedure........................................................................................................ 6-24
13.0 REMOVE AND REPLACE LOW AND HIGH PRESSURE LINES.............................................................. 6-25
13.1 High Pressure Line Identification Tags.................................................................................................................. 6-25
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© 2016 McNeilus Truck and Manufacturing, Inc
1.0 Overview
Component Remove and Replace
1. Turn OFF each tank valve (Figure 1), main tanks and
side saddle tank(s) if installed. Location of the tank
valves varies by vehicle. As already stated, the tanks will
remain pressurized.
The content of this manual was provided by Mainstay
Fuel Technologies for the MA20 fuel management module
system. If you have questions regarding any of the tasks
provided in this section, contact Mainstay.
Mainstay Fuel Technologies
100 Hurricane Creek Road, Piedmont, SC 29673
Telephone: 864-655-6905
Service number: 1-844-332-3775
This section describes how to remove, replace, or install the
CNG fuel module and its major serviceable components.
• Depressurizing the CNG System
Figure 1
• Fuel Module
2. Start the vehicle and allow it to run until it stalls.
-- Upper Covers
3. Attempt to start the vehicle again. If it starts, let it run
until it stalls again. Repeat this step until the vehicle no
longer starts. This ensures that all CNG in the system
downstream of the tanks is consumed.
-- Lower Covers
• Door Interlock (Vehicle Starter Interrupt)
• Fill Receptacles
WARNING
-- Defueling
Even if the truck has stalled after running it
out of fuel, and you think all fuel has been
depleted, check the high pressure gauge to
make sure it is at zero.
If the gauge is not at zero, continue to
deplete the fuel until the gauge reads zero.
Failure to comply may result in serious
personal injury or death.
-- NGV1
-- CL-50
• Low Pressure Solenoid Assembly
• Solenoid Coil
• Transducer
• Signal Conditioner
• Fuel Regulator
4. Perform your company’s Lockout/Tagout procedure.
If your company does not have a Lockout/Tagout
procedure, follow OSHA 1910.147 Lockout/Tagout and
1910.146 Confined Space as appropriate.
2.0 Torque Standards
Always torque fasteners, clamps, hydraulic line fittings and
nuts per specifications. Failure to do so can cause a part
to fail, which may result in serious injury or death. Do not
under or over-torque fasteners, clamps, hydraulic fittings
and nuts to compensate for not having a torque wrench.
Unless otherwise stated, see torque standards in the
Preventive Maintenance Section of this manual.
5. Turn off battery disconnect switch (if equipped) or
disconnect all battery cables.
WARNING
For trucks without a battery disconnect switch,
to prevent accidental vehicle start-up, which
could cause death or serious injury, disconnect
battery cables (negative cable first) before
proceeding.
3.0 Depressurizing the CNG Fuel
System
Disconnect negative (-) battery cable first. If
positive (+) cable should contact ground with
negative (-) cable connected, the resulting
sparks can cause a battery explosion, which
could result in death or serious injury.
When performing any maintenance that requires
removing or replacing components, including removing
and reinstalling the fuel module, completely depressurize
the CNG system. The CNG tanks do NOT need to be
depressurized.
Perform ALL of these steps to ensure that there is NO
system pressure (except the tanks). Do not skip this
process or any steps in this process. Failure to do so can
cause a part to fail, which may result in serious injury or
death.
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Component Remove and Replace
8. Ensure that the Tank Pressure gauge (high pressure)on
the fuel control module (Figure 4, Item 1) reads 0 PSI.
The Output Pressure gauge (Figure 4, Item 2) should
also read 0 PSI. If they do not read 0 PSI, ensure that
all tank valves are fully closed and the purge valve is
completely open.
6. Leave the Manual Shut-Off Valve on the fuel module in
the ‘ON’ position (Figure 2, Item 1).
1
1
Figure 2
7. The system purge valve is located inside the fuel
module side access maintenance door (Figure 3, Item
1) on the side of the fuel module. Open the access
door, locate the purge valve (Figure 3, Item 2), and use
a wrench to open the valve to relieve any remaining
pressure in the tank line, the fuel module, and the
remote fill line. Leave the purge valve open.
2
Figure 4
6
9. Continue with removal and replacement of fuel module
or system component as required.
1
4.0 Remove and Replace Fuel
Module
Along with inspections, some time during the normal life
span of the vehicle, the CNG system will require repair
and maintenance. To more easily and effectively perform
maintenance and replace various system components, the
fuel module will have to be removed and reinstalled.
2
This section describes how to remove and reinstall the fuel
module.
Tools required:
• 1/2” wrench
• 1/2” socket
Figure 3
• 15/16” wrench
• Torque wrench
• Pliers
• Service clamps
4.1 CNG Depressurization
Prepare the vehicle for fuel module removal.
Depressurize the CNG system as shown in Section 3.0
Depressurizing the CNG Fuel System.
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© 2016 McNeilus Truck and Manufacturing, Inc
Component Remove and Replace
4.2 Fuel Module Removal
4. Use nut driver, screw driver, or pliers as needed to
loosen radiator hose clamps and disconnect upper and
lower coolant lines (Figure 5, Items 1 and 2). Mark the
coolant lines (upper and lower) for proper installation
later on.
After preparing the vehicle and the CNG system is
completely depressurized (except the tanks), review Figure
5, and then perform the steps in this section to remove and
reinstall the fuel module.
5. Gently move all coolant lines and harnesses safely out
of the way (Figure 7).
Figure 5 shows the hoses, lines, and connector on the rear
of the fuel module that will be loosened and removed.
• Item 1 - Upper coolant line
• Item 2 - Lower coolant line
• Item 3 - Deutsch connector
• Item 4 - Low pressure CNG line
• Item 5 - High pressure (tank) CNG line
• Item 6 - Remote fill CNG line (not visible)
1
2
3
Figure 7
6. Disconnect the low pressure CNG line (Figure 8). Use a
backing wrench to hold the fitting to prevent damage to
the module. Move the line safely out of the way.
4
6
5
6
Figure 5
1. Perform your company’s Lockout/Tagout procedure.
If your company does not have a Lockout/Tagout
procedure, follow OSHA 1910.147 Lockout/Tagout and
1910.146 Confined Space as appropriate.
2. Disconnect the Deutsch connector (Figure 5, Item 3).
3. Properly install service clamps on both coolant lines
(Figure 6) to prevent a coolant spill. If a spill occurs,
properly clean the spill per all applicable laws.
Figure 8
Figure 6
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Component Remove and Replace
7. Disconnect the remote fill port supply line (Figure 9, Item
1). Use a backing wrench to hold the fitting to prevent
damage to the module. Move the line safely out of the
way.
10. Loosen, remove, and retain the left side mounting bolts
(Figure 11, Item 1).
1
1
Front
Figure 11
11. Loosen, remove, and retain the right side mounting bolts
(Figure 12, Item 1).
Figure 9
8. Disconnect the high pressure CNG line coming from
the tank (Figure 10). Use a backing wrench to hold the
fitting to prevent damage to the module. Move the line
safely out of the way.
Front
1
6
Figure 10
Figure 12
9. Before loosening and removing the fuel module
mounting bolts, safely and completely support the fuel
module with an adequate floor jack and or strapping.
12. Safely and completely support the fuel module with an
adequate floor jack and or strapping and slowly lower
the fuel module away from the vehicle mount bracket.
13. Continue with removing the upper, lower, or both fuel
module housing covers as needed.
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Component Remove and Replace
4.3 Fuel Module Upper and Lower
Covers
4.3.2 Lower Cover Removal and Installation
To remove the lower cover, it is not always required to
remove the fuel module from the vehicle mounting bracket.
However, if removing the fuel module is required, perform
the steps as show in Section 4.2 Fuel Module Removal.
After removing the fuel module, to gain access to the
serviceable components, remove the upper, lower, or both
fuel module housing covers as needed.
1. Remove the fuel module from the vehicle if needed.
4.3.1 Upper Cover Removal and Installation
2. Remove and retain the left side lower cover bolts.
1. Remove the fuel module from the vehicle as shown in
Section 4.2 Fuel Module Removal.
2. Remove and retain the left side upper cover bolts.
1
1
Front
Front
Figure 15
3. Remove and retain the right side lower cover bolts.
Figure 13
3. Remove and retain the right side upper cover bolts.
Front
1
Front
Figure 16
1
4. Set the lower cover aside and perform the necessary
maintenance to the fuel module.
Figure 14
5. To reinstall the lower cover, align and install the left side
lower cover bolts.
4. Set the upper cover aside and perform the necessary
maintenance to the fuel module.
6. Align and install the right side lower cover bolts.
5. To reinstall the upper cover, align and install the left side
upper cover bolts.
7. Either continue with component removal and
replacement or reinstall the Fuel Module (if removed) as
shown in Section 4.4 Fuel Module Installation.
6. Align and install the right side upper cover bolts.
7. Either continue with component removal and
replacement or reinstall the fuel module as shown in
Section 4.4 Fuel Module Installation.
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Component Remove and Replace
4.4 Fuel Module Installation
4.5 Leak Detection
To reinstall the fuel module, perform the following tasks.
1. Perform your company’s Lockout/Tagout procedure.
If your company does not have a Lockout/Tagout
procedure, follow OSHA 1910.147 Lockout/Tagout and
1910.146 Confined Space as appropriate.
1. Perform your company’s Lockout/Tagout procedure.
If your company does not have a Lockout/Tagout
procedure, follow OSHA 1910.147 Lockout/Tagout and
1910.146 Confined Space as appropriate.
2. Once the system has been repaired, all components
properly re-installed, and the system is pressurized, use
a liquid leak detector and carefully check all fittings for
leaks.
2. Safely and completely support the fuel module with an
adequate floor jack and or strapping and slowly lift the
fuel module in place under the vehicle mount bracket.
3. On the regulator, pay special attention to and observe
the reducing tee-connection located on the low pressure
tube (Figure 17, Item 1).
3. Ensure upper and lower covers are installed. See
Section 4.3 Fuel Module Upper and Lower Covers.
4. Align the fuel module mounting holes with the vehicle
bracket mounting holes. Reinstall and tighten the four
fuel module mounting bolts (Figure 11, Item 1 and
Figure 12, Item 1).
5. Move all the coolant lines, CNG lines, and the harness
into place. (Figure 6).
6. Reconnect and tighten the high pressure CNG line
coming from the tank (Figure 10). Use a backing wrench
to hold the fitting to prevent damage to the module and
use a torque wrench to tighten the fitting to 40 ft.-lbs.
7. Reconnect and tighten the remote fill CNG line (Figure
9). Use a backing wrench to hold the fitting to prevent
damage to the module and use a torque wrench to
tighten the fitting to 40 ft.-lbs.
6
1
Figure 17
8. Reconnect and tighten the low pressure CNG line
(Figure 8). Use a backing wrench to hold the fitting to
prevent damage to the module and use a torque wrench
to tighten the fitting to 40 ft.-lbs.
a. If a leak is detected at the reducing tee, use a
backing wrench to hold the fittings, and tighten
the compression fittings one (1) flat at a time and
check for leaks again between each turn until the
line no longer leaks.
b. Use caution if one of these compression fittings
is leaking. Do not over-tighten and damage the
connection.
4. After checking and repairing leaks in the reducing
tee area, check for leaks on the rest of the fuel
module fittings. If a leak is detected (Figure 18),
depressurize the system again as shown in Section
3.0 Depressurizing the CNG Fuel System.
9. Properly reconnect upper and lower coolant lines
(Figure 5, Items 1 and 2).
10. Remove service clamps from coolant lines (Figure 6).
11. Connect the Deutsch connector (Figure 5, Item 3) and
listen for the audible click to ensure the connector is fully
seated.
12. Turn on battery disconnect switch (if equipped) or
connect all battery cables.
13. Close the purge valve (Figure 3, Item 1).
14. Ensure that the manual shutoff valve (Figure 1, Item 1)
is still open.
15. Slowly open the tank valves.
16. Check the tank pressure gauge (high pressure) (Figure
4, Item 1) to confirm a rise in fuel pressure. The output
pressure gauge (low pressure) (Figure 4, Item 2) may
not register pressure until the vehicle ignition is turned to
the On position.
17. Check for leaks as shown in Section 4.5 Leak Detection.
18. Remove Lockout/Tagout from the refuse vehicle. If your
company does not have a Lockout/Tagout procedure,
follow OSHA 1910.147 Lockout/Tagout and 1910.146
Confined Space as appropriate.
Figure 18
5. Check the leaky connection for a damaged O-Ring, line
or fitting damage, cracks, debris, etc.
19. Return vehicle to service.
CNG — Service Manual
6. Repair, reconnect, torque to specifications, and repressurize the system.
6-8
© 2016 McNeilus Truck and Manufacturing, Inc
Component Remove and Replace
5.2 Door Interlock Installation
7. Use a liquid leak detector and check all fittings again for
leaks.
1. Perform your company’s Lockout/Tagout procedure.
If your company does not have a Lockout/Tagout
procedure, follow OSHA 1910.147 Lockout/Tagout and
1910.146 Confined Space as appropriate.
8. Repeat Steps 1 through 5 until all leaks are repaired.
9. If no leaks are detected, remove Lockout/Tagout from
the refuse vehicle. If your company does not have a
Lockout/Tagout procedure, follow OSHA 1910.147
Lockout/Tagout and 1910.146 Confined Space as
appropriate.
2. Turn off battery disconnect switch (if equipped) or
disconnect all battery cables.
WARNING
10. Return the vehicle to service.
For trucks without a battery disconnect switch,
to prevent accidental vehicle start-up, which
could cause death or serious injury, disconnect
battery cables (negative cable first) before
proceeding.
5.0 Connecting the Fuel Module
Door Interlock
Disconnect negative (-) battery cable first. If
positive (+) cable should contact ground with
negative (-) cable connected, the resulting
sparks can cause a battery explosion, which
could result in death or serious injury.
When connected properly, the fuel module door interlock
(Figure 19, Item 1) interrupts the vehicle starter control
circuit if the fuel module door is open. When the fuel
module door is closed, the door interlock allows the vehicle
to start.
Door Interlock McNeilus part number 1549767.
3. Locate the vehicle starter. Starter location, cable size
and type varies by vehicle.
Tools required:
• Wire cutters
4. Ensure there is no battery voltage at the starter.
• Appropriate sized splice or wire connector
5. Disconnect and remove the starter GROUND wire
(Figure 20, Item 1) from the vehicle starter circuit.
Disconnect and remove only the ground wire and ensure
all other wires stay in place and properly connected.
Starter circuit type, ground wire location, wire size, and
connections vary by vehicle.
• Wrench (for starter ground wire nut, size varies)
• Heat shrink and or electrical tape
• Proper sized splice or split nut connector
1
1
Figure 19
5.1 Vehicle Preparation
It is not necessary to depressurize the CNG system to
install the fuel module door interlock. However, the vehicle
electrical system must be completely disabled.
Figure 20
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Component Remove and Replace
6.0 Remove and Replace Fill
Receptacles
6. Properly splice/connect the GROUND wire disconnected
from the starter circuit in Figure 20, to the door interlock
wire of the fuel module door interlock circuit as shown in
Figure 21, Item 1.
During the course of normal operation and use, the three fill
receptacles (Figure 22, Item 1) and their O-rings installed in
the main panel (Figure 22, Item 2) can be damaged or worn
and require replacement. This section describes how to
remove and replace all three fill receptacles.
1
1
Figure 21
7. Properly wrap and/or heat shrink the spliced connection.
2
8. Ensure all wires are safely wrapped, routed, and
secured.
6
9. Turn on battery disconnect switch (if equipped) or
connect all battery cables.
Figure 22
When replacing any of the fill receptacles, ensure the
system (except the tanks) is completely depressurized
before disconnecting any lines.
10. Remove Lockout/Tagout from the refuse vehicle. If your
company does not have a Lockout/Tagout procedure,
follow OSHA 1910.147 Lockout/Tagout and 1910.146
Confined Space as appropriate.
It is not necessary to remove the fuel module from the
vehicle to replace a fill receptacle.
11. Test the door interlock switch for proper operation as
follows:
Tools required:
• 3/4” thin profile wrench
a. Leave the fuel module door open. The vehicle
should not crank at all when the key is turned.
b. Close the fuel module door. The vehicle should
crank when the key is turned.
• 3/4” thin profile crows foot wrench
• 7/8” thin profile crows foot wrench
• 1 1/4” thin profile crows foot wrench
12. Return the vehicle to service.
• 1 1/16” thin profile wrench
• Torque wrench
6.1 CNG Depressurization
Prepare the vehicle for receptacle replacement.
Depressurize the CNG system as shown in Section 3.0
Depressurizing the CNG Fuel System.
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© 2016 McNeilus Truck and Manufacturing, Inc
6.2 Receptacle Removal and
Replacement
Component Remove and Replace
4. After the area around the port is clean, remove the
damaged receptacle.
5. Apply only one of the following approved lubricants to
the O-ring on the new receptacle. Approved lubricants
are as follows:
After properly preparing the vehicle and the CNG system
is completely depressurized, perform the following steps
to remove and replace each receptacle. Figure 23 shows
receptacle location and Table 1 - Receptacle Details
details the wrench size and torque values needed for each
receptacle.
-- Super O-Lube, Parker
-65° to 400° (F);
-53.8° to 204.4° (C)
-- DC-55, Dow Corning Co.
-65° to 275° (F);
-53.8° to 135° (C)
1
-- Celvacene, Consolidated Vacuum Corp.
-40° to 200° (F);
-40° to 93.3° (C)
Failure to use an approved O-ring lubricant may cause
O-ring degradation which may cause leaks over time.
6. Use a backing wrench to hold the fitting and use a
torque wrench to tighten the new receptacle per the
torque values shown in Table 1 - Receptacle Details.
2
7. Close the purge valve.
8. Slowly open the tank valves.
9. Check the tank pressure gauge (high pressure) (Figure
4, Item 1) to confirm a rise in fuel pressure. The output
pressure gauge (low pressure) (Figure 4, Item 2) may
not register pressure until the vehicle ignition is turned to
the On position.
3
10. Check for leaks as shown in Section 4.5 Leak Detection.
Figure 23
11. Remove Lockout/Tagout from the refuse vehicle. If your
company does not have a Lockout/Tagout procedure,
follow OSHA 1910.147 Lockout/Tagout and 1910.146
Confined Space as appropriate.
Table 1 - Receptacle Details
Receptacle Name
Figure Location
McNeilus Part
Number
Working Details
12. Return the vehicle to service.
Defueling
Receptacle
Figure 23, Item 1
PN 1551273
Use a ¾” thin profile backing
wrench.
Torque to 30 ft.-lbs. using 7/8” thin
profile crows foot wrench.
NGV-1 Receptacle
Figure 23, Item 2
PN 1541752
Use a ¾” thin profile backing
wrench.
Torque to 30 ft.-lbs. using ¾” thin
profile crows foot wrench.
CL-50 Receptacle
Figure 23, Item 3
PN 1496438
Use a 1 1/16 ” thin profile backing
wrench.
Torque to 43 ft.-lbs. using a 1 1/4”
thin profile crows foot wrench.
7.0 Remove and Replace Low
Pressure Solenoid Assembly
When replacing the low pressure solenoid assembly (Figure
24), ensure that the system is completely depressurized
(except the tanks) before disconnecting any lines.
If just the solenoid coil needs replaced, see Section 8.0
Remove and Replace Solenoid Coil.
Low pressure solenoid is McNeilus part number 1530737.
Tools required:
1. Perform your company’s Lockout/Tagout procedure.
If your company does not have a Lockout/Tagout
procedure, follow OSHA 1910.147 Lockout/Tagout and
1910.146 Confined Space as appropriate.
• 1 1/8” wrench
2. Use a backing wrench to hold the fitting (Figure 23)
for the receptacle. Loosen, but do not yet remove the
damaged receptacle.
• Wire cutters and crimping tool for splices
• 15/16” wrench
• Torque wrench
3. Use compressed air to remove dirt and debris from the
receptacle port and the area around the port.
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Component Remove and Replace
7.1 CNG Depressurization
4. Locate the low pressure solenoid assembly (Figure 26)
and disconnect the Deutsch connector (Figure 25, Item
1) attached to the solenoid assembly from the wiring
harness.
Prepare the vehicle for low pressure solenoid assembly
replacement.
Depressurize the CNG system as shown in Section 3.0
Depressurizing the CNG Fuel System.
5. Clip both wires close to the old solenoid coil (Figure 25,
Item 2) leaving as much wire as possible for connecting
the new solenoid back to the Deutsch connector. Retain
the Deutsch connector.
7.2 Low Pressure Solenoid Assembly
Removal and Replacement
This section describes how to remove and replace the low
pressure solenoid assembly.
Figure 24 shows the low pressure solenoid assembly as
shipped.
1
• Item 1 - Low pressure solenoid assembly
• Item 2 - Solenoid coil
• Item 3 - Solenoid coil wire
2
• Item 4 - 90° elbow
• Item 5 - Splices
• Item 6 - Solenoid assembly bulkhead fitting
Figure 25
6. Loosen the tubing from the solenoid assembly (Figure
26, Item 1).
1
6
7. Loosen and remove the mounting nut from the solenoid
assembly bulkhead fitting (Figure 26, Item 2) and
remove the solenoid assembly from the housing.
6
3
1
2
4
2
5
Figure 26
8. Insert the new 90°elbow into the new solenoid assembly
and tighten the elbow only until the washer is flat against
the assembly and the O-ring is not visible (Figure
27, Item 1) Do not torque this nut until the elbow is
connected to the tubing later in this process.
Figure 24
After properly preparing the vehicle and the CNG system
is completely depressurized, use the following steps to
remove and replace the solenoid assembly.
1. Perform your company’s Lockout/Tagout procedure.
If your company does not have a Lockout/Tagout
procedure, follow OSHA 1910.147 Lockout/Tagout and
1910.146 Confined Space as appropriate.
1
2. Remove the fuel module from the vehicle mount. See
Section 4.0 Remove and Replace Fuel Module.
3. After removing the fuel module, remove the fuel module
covers. See Section 4.3 Fuel Module Upper and Lower
Covers.
Figure 27
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Component Remove and Replace
9. Remove the new mounting nut from the new solenoid
assembly bulkhead fitting (Figure 28, Item 1).
To prevent damage to fittings, connectors, and tubing,
use a backing wrench to hold all connectors.
13. Splice the new solenoid wires to the wires on the
Deutsch connector. (Figure 31, Item 1).
14. Reconnect the Deutsch connector to the wiring harness
(Figure 31, Item 2).
1
1
2
Figure 28
10. Insert the new bulkhead fitting through the fuel module
housing, properly align the new solenoid assembly,
reinstall the nut (Figure 29, Item 1), use a backing
wrench to hold the fitting, and use a torque wrench to
tighten the nut to 40 ft.-lbs.
Figure 31
15. Reinstall the covers. See Section 4.3 Fuel Module
Upper and Lower Covers.
16. Reinstall the fuel module. See Section 4.4 Fuel Module
Installation.
17. Close the purge valve.
18. Slowly open the tank valves.
19. Check the tank pressure gauge (high pressure) (Figure
4, Item 1) to confirm a rise in fuel pressure. The output
pressure gauge (low pressure) (Figure 4, Item 2) may
not register pressure until the vehicle ignition is turned to
the On position.
1
Figure 29
11. Use a wrench and align the solenoid assembly elbow
to the tubing fitting (Figure 30, Item 1), use a backing
wrench to hold the fitting, and use a torque wrench to
tighten the tubing fitting to 40 ft.-lbs.
20. Check for leaks as shown in Section 4.5 Leak Detection.
21. Remove Lockout/Tagout from the refuse vehicle. If your
company does not have a Lockout/Tagout procedure,
follow OSHA 1910.147 Lockout/Tagout and 1910.146
Confined Space as appropriate.
12. When the tubing is installed and properly torqued, use
a backing wrench to hold the fitting, and use a torque
wrench to tighten the nut on the solenoid side of the
elbow (Figure 30, Item 2) to 43 ft.-lbs.
22. Return vehicle to service.
2
1
Figure 30
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Component Remove and Replace
8.0 Remove and Replace Solenoid
Coil
4. Locate the solenoid (Figure 33, Item 1) in the fuel
module. (Fuel module removed from vehicle for ease of
illustration only.)
It may be determined that only the solenoid coil needs
replacement. The coil can be replaced without removing the
fuel module or the solenoid assembly.
1
This section describes how to remove and replace just the
solenoid coil.
The solenoid coil kit is McNeilus part number 1549855.
Tools required:
• 3/4” wrench
• Torque wrench
Figure 32
• Wire cutters
5. Locate the solenoid coil on the top of the solenoid
(Figure 33, Item 1).
• Crimping tool for splices
8.1 Vehicle Preparation
The CNG system does not need to be depressurized to
remove and replace the solenoid coil. However, the vehicle
electrical system must be completely disabled.
1
8.2 Solenoid Coil Removal and
Replacement
After properly preparing the vehicle, use the following steps
to remove and replace the solenoid coil.
6
The fuel module or the solenoid assembly do not need to
be removed from the vehicle to replace the solenoid coil.
1. Perform your company’s Lockout/Tagout procedure.
If your company does not have a Lockout/Tagout
procedure, follow OSHA 1910.147 Lockout/Tagout and
1910.146 Confined Space as appropriate.
Figure 33
6. Disconnect the solenoid harness Deutsch connector
(Figure 34, Item 1).
2. Turn off battery disconnect switch (if equipped) or
disconnect all battery cables.
WARNING
For trucks without a battery disconnect switch,
to prevent accidental vehicle start-up, which
could cause death or serious injury, disconnect
battery cables (negative cable first) before
proceeding.
1
Disconnect negative (-) battery cable first. If
positive (+) cable should contact ground with
negative (-) cable connected, the resulting
sparks can cause a battery explosion, which
could result in death or serious injury.
Figure 34
3. Remove the lower covers from the fuel module as
shown in Section 4.3.2 Lower Cover Removal and
Installation on page 6-7.
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© 2016 McNeilus Truck and Manufacturing, Inc
Component Remove and Replace
9.0 Remove and Replace
Transducer
7. Locate the coil retaining bolt (Figure 35, Item 1). Use
a ¾” wrench to loosen, remove and retain the bolt.
Remove the coil.
When replacing the transducer, ensure the system (except
the tanks) is completely depressurized before disconnecting
any lines.
It is easier to replace the transducer if the fuel module is
removed from the vehicle. However, it is possible to access,
remove, and replace the transducer with the fuel module
installed on the vehicle.
1
The process described in this section assumes that the
fuel module is not installed on the vehicle. See Section 4.0
Remove and Replace Fuel Module.
Transducer is McNeilus part number 1470836.
Tools required:
• 7/8” deep well socket
• 1/2” drive socket wrench
Figure 35
• Torque wrench
8. Assemble the two pin connector on the new coil and
connect that to the Deutsch connector on the wiring
harness (Figure 34, Item 1).
• 3” extension (optional)
• 7/8” crows foot wrench (optional)
9. Fit the new coil into the solenoid assembly and tighten
the bolt (Figure 35, Item 1) to 15 in. lbs.
9.1 CNG Depressurization
10. Turn on battery disconnect switch (if equipped) or
connect all battery cables.
Prepare the vehicle for transducer removal and
replacement.
11. Remove Lockout/Tagout from the refuse vehicle. If your
company does not have a Lockout/Tagout procedure,
follow OSHA 1910.147 Lockout/Tagout and 1910.146
Confined Space as appropriate.
Depressurize the CNG system as shown in Section 3.0
Depressurizing the CNG Fuel System.
9.2 Transducer Removal and
Replacement
12. Cycle the vehicle ignition off and on to confirm that the
solenoid makes a distinct clicking sound as the vehicle
ignition is turned off and on.
13. Start the vehicle to confirm gas flow through the
solenoid.
1. Perform your company’s Lockout/Tagout procedure.
If your company does not have a Lockout/Tagout
procedure, follow OSHA 1910.147 Lockout/Tagout and
1910.146 Confined Space as appropriate.
14. Reinstall the lower covers. See Section 4.3.2 Lower
Cover Removal and Installation.
2. Remove the fuel module from the vehicle. See Section
4.0 Remove and Replace Fuel Module.
15. Return vehicle to service.
3. Remove the fuel module lower cover and position the
module as shown in Figure 36. See Section 4.3.2 Lower
Cover Removal and Installation.
4. Locate the transducer (Figure 36, Item 1).
1
Figure 36
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Component Remove and Replace
10.0 Remove and Replace Signal
Conditioner
5. Disconnect the transducer from the wiring harness
(Figure 37, Item 1).
1
When replacing the signal conditioner, the CNG system
does not need to be depressurized.
• Signal Conditioner (1.75 to .30 voltage range),
McNeilus part number, 1549857
• Signal Conditioner (3.33 to .45 voltage range),
McNeilus part number, 1549859
• Signal Conditioner (2.48 to .54 voltage range),
McNeilus part number, 1549859
Figure 37
6. Remove the transducer from the regulator. Use a deep
well 7/8” socket to remove the transducer. If a deep well
7/8” socket is not available, use a 3” extension and a
7/8” crow’s foot wrench.
Tools required:
• Wire cutters
• Crimping tool for splices
• Tie wraps
7. Thoroughly inspect the regulator port prior to
installing the new transducer and remove any debris.
Compressed air is the recommended method of debris
removal.
10.1 Vehicle Preparation
Prepare the vehicle for signal conditioner removal and
replacement.
8. Install the new transducer, use a backing wrench to hold
the fitting, and use a torque wrench to tighten to
15 ft.-lbs.
The CNG system does not need to be depressurized to
install the signal conditioner. However, ensure that the
vehicle electrical system is completely disabled.
9. Reconnect the wiring harness to the transducer and
ensure that the connection is fully engaged and
snapped into place.
6
10.2 Signal Conditioner Removal and
Replacement
10. Reinstall the covers. See Section 4.3 Fuel Module
Upper and Lower Covers.
1. Perform your company’s Lockout/Tagout procedure.
If your company does not have a Lockout/Tagout
procedure, follow OSHA 1910.147 Lockout/Tagout and
1910.146 Confined Space as appropriate.
11. Reinstall the fuel module. See Section 4.4 Fuel Module
Installation.
12. Close the purge valve.
2. Turn off battery disconnect switch (if equipped) or
disconnect all battery cables.
13. Slowly open the tank valves.
14. Check the tank pressure gauge (high pressure) (Figure
4, Item 1) to confirm a rise in fuel pressure. The output
pressure gauge (low pressure) (Figure 4, Item 2) may
not register pressure until the vehicle ignition is turned to
the On position.
WARNING
For trucks without a battery disconnect switch,
to prevent accidental vehicle start-up, which
could cause death or serious injury, disconnect
battery cables (negative cable first) before
proceeding.
15. Check for leaks as shown in Section 4.5 Leak Detection.
16. Remove Lockout/Tagout from the refuse vehicle. If your
company does not have a Lockout/Tagout procedure,
follow OSHA 1910.147 Lockout/Tagout and 1910.146
Confined Space as appropriate.
Disconnect negative (-) battery cable first. If
positive (+) cable should contact ground with
negative (-) cable connected, the resulting
sparks can cause a battery explosion, which
could result in death or serious injury.
17. Return vehicle to service.
3. Leave the fuel module mounted to the vehicle.
4. Remove the lower cover from the fuel module
housing. See Section 4.3.2 Lower Cover Removal and
Installation.
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© 2016 McNeilus Truck and Manufacturing, Inc
Component Remove and Replace
5. Locate the signal conditioner (Figure 38, Item 1).
9. Connect the new signal conditioner to the Deutsch
connector (Figure 41).
1
Figure 41
Figure 38
10. Push the signal conditioner wiring harness back into
the fuel module and secure the harness and signal
conditioner to the tubing with tie wraps like it was in Step
4 (Figure 42, Item 1).
6. Remove the tie wraps that hold the signal conditioner
and its wiring harness to the tubing. Note where these
tie wraps are located.
7. Gently pull down on the signal conditioner wiring
harness to access the Deutsch connector (Figure 39).
6
1
Figure 42
11. Ensure all wires are safely wrapped, routed, and
secured.
Figure 39
8. Disconnect the old signal conditioner Deutsch connector
from the wiring harness (Figure 40).
12. Reinstall the covers. See Section 4.3 Fuel Module
Upper and Lower Covers.
13. Reinstall the fuel module. See Section 4.4 Fuel Module
Installation.
14. Turn on battery disconnect switch (if equipped) or
connect all battery cables.
15. Remove Lockout/Tagout from the refuse vehicle. If your
company does not have a Lockout/Tagout procedure,
follow OSHA 1910.147 Lockout/Tagout and 1910.146
Confined Space as appropriate.
16. Test the system for proper operation.
17. Return the vehicle to service.
Figure 40
© 2016 McNeilus Truck and Manufacturing, Inc.
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Component Remove and Replace
11.0 Remove and Replace Fuel
Regulator
11.2 Fuel Regulator Removal and
Replacement
1. Perform your company’s Lockout/Tagout procedure.
If your company does not have a Lockout/Tagout
procedure, follow OSHA 1910.147 Lockout/Tagout and
1910.146 Confined Space as appropriate.
When replacing the fuel regulator, ensure that the system is
completely depressurized before disconnecting any lines to
remove the fuel module.
Fuel regulator is McNeilus part number 1501936.
2. Turn off battery disconnect switch (if equipped) or
disconnect all battery cables.
Tools required:
• 1/2” open ended wrench
WARNING
• 1/2” drive socket wrench
For trucks without a battery disconnect switch,
to prevent accidental vehicle start-up, which
could cause death or serious injury, disconnect
battery cables (negative cable first) before
proceeding.
• 7/16” wrench
• 9/16” open ended wrench
• 7/8” open ended wrench
• 3/4” open ended wrench
Disconnect negative (-) battery cable first. If
positive (+) cable should contact ground with
negative (-) cable connected, the resulting
sparks can cause a battery explosion, which
could result in death or serious injury.
• 13/16” crows foot wrench
• 15/16” crows foot wrench
• 15/16” socket
• 15/16” open ended wrench
3. Remove the fuel module from the vehicle. See Section
4.0 Remove and Replace Fuel Module.
• Nut drivers for coolant line hose clamps
• Pliers
• Torque wrench
4. Remove upper and lower covers from the fuel module
housing. See Section 4.3 Fuel Module Upper and Lower
Covers.
• Service Clamps
5. Position the fuel module as shown in Figure 43.
• 5 mm Allen wrench
6
11.1 CNG Depressurization
Prepare the vehicle for regulator removal and replacement.
Depressurize the CNG system as shown in Section 3.0
Depressurizing the CNG Fuel System.
At each step during removal and replacement of the
regulator and all components, check all tubes, fittings, and
O-rings for wear. Also remove any debris, dust, lint, etc.
that could cause a leak when the system is reassembled,
reinstalled and pressure tested.
Figure 43
6. Begin removing the low pressure tube by using a
backing wrench to hold the fitting and loosen the low
pressure tube from the regulator (Figure 44, Item 1).
1
Figure 44
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Component Remove and Replace
7. Use 7/8” wrench to loosen the other end of low pressure
tube from the tee (Figure 45, Item 1).
10. Use a backing wrench to hold the fitting and loosen
the other end of the high pressure tube from the filter
manifold (Figure 48, Item 1).
1
1
Figure 45
8. Remove the low pressure tube from the fuel module
(Figure 46, Item 1).
Figure 48
11. Remove the high pressure tube from the fuel module
(Figure 49).
1
6
1
Figure 46
9. Begin removing the high pressure tube by using a
backing wrench to hold the fitting and loosen the high
pressure tube from the regulator (Figure 47, Item 1).
Figure 49
12. Begin removing the Pressure Relief Device (PRD) vent
line by rotating the fuel module for access to the PRD
vent line (Figure 50). Use an open ended wrench to
loosen the tubing at the PRD vent line elbow (Figure 50,
Item 1).
1
1
Figure 47
Figure 50
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Component Remove and Replace
13. Rotate the fuel module again to access and loosen the
other end of the PRD vent line (Figure 51, Item 1).
17. Locate and loosen the two coolant line hose clamps on
the coolant lines (Figure 55, Item 1)
1
1
Figure 55
18. Remove the regulator by removing the two regulator
mounting screws (Figure 56, Item 1). Retain these
screws for installation of the new regulator.
Figure 51
14. Remove the PRD vent line from the fuel module (Figure
52, Item 1).
1
1
6
Figure 52
15. Locate the transducer (Figure 53, Item 1).
Figure 56
19. Remove the regulator from the fuel module (Figure 57).
Split the old coolant lines as needed to more easily
remove the regulator.
1
Figure 53
16. Disconnect the transducer’s Deutsch connector (Figure
54, Item 1) and gently move the connector out of the
way.
1
Figure 57
Figure 54
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Component Remove and Replace
20. Remove and discard the nut and ferrule as shipped on
the new regulator elbow fitting (Figure 58, Item 1).
23. Ensure both coolant hoses are fully on the brass barbed
fittings and secure both hoses by tightening the clamps.
Do NOT over-tighten the clamps. Over-tightening may
damage the coolant hoses.
1
1
Figure 58
Figure 61
21. Position the replacement regulator inside the fuel
module, ensure the hose clamps are already loosely
installed on the coolant hoses and line up the coolant
hoses with the brass barbed fittings (Figure 59, Item
1). Push the coolant hoses completely on to the brass
barbed fittings. Do not tighten the hose clamps yet.
24. Connect the transducer to the wiring harness, (Figure
62, Item 1) and listen for the audible click to ensure the
connector is fully seated.
1
6
Figure 62
1
Figure 59
22. Secure the regulator to the fuel module using the
mounting screws retained from Step 18.
1
Figure 60
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Component Remove and Replace
25. Properly position, align, and reinstall the PRD vent line
(Figure 63). Finger tighten the fittings at both ends.
28. Properly position, align, and reinstall the high pressure
line (Figure 64, Item 1). Finger tighten the fittings at both
ends.
26. Ensure each fitting is still properly aligned and use a
wrench to tighten each fitting 1/2 turn at a time until
snug (Figure 63, Items 1 and 2).
29. Ensure each fitting is still properly aligned and use a
wrench to tighten each fitting 1/2 turn at a time until
snug (Figure 64, Item 1).
27. Use a backing wrench to hold the fittings and use a
torque wrench to tighten the nuts on both ends to
30 ft.-lbs.
1
1
Figure 64
30. Use a backing wrench to hold each fitting and use
a torque wrench to tighten both fittings to 30 ft.-lbs.
(Figure 65, Items 1 and 2).
1
6
2
Figure 63
2
Figure 65
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Component Remove and Replace
31. Properly position, align and reinstall the low pressure
line (Figure 66).
35. Ensure that the fitting is still properly aligned and use
a wrench to tighten 1/2 turn at a time until snug (Figure
69, Item 1).
36. Use a backing wrench to hold the fitting and use a
torque wrench to tighten the nut to 40 ft.-lbs.
1
Figure 66
32. Correctly align the compression fitting end of the low
pressure line, rotate tube onto O-ring Face Seal fitting
(ORFS) and finger tighten the nut (Figure 67, Item 1).
Figure 69
37. Check for leaks as shown in Section 4.5 Leak Detection.
38. Remove Lockout/Tagout from the refuse vehicle. If your
company does not have a Lockout/Tagout procedure,
follow OSHA 1910.147 Lockout/Tagout and 1910.146
Confined Space as appropriate.
1
39. Test the system for proper operation.
40. Return the vehicle to service.
Figure 67
33. Use a backing wrench to hold the fitting (Figure 68, Item
1) and torque the ORFS fitting to 40 ft.-lb.
1
Figure 68
34. On the other end of the low pressure line, align and
finger tighten the fitting.
© 2016 McNeilus Truck and Manufacturing, Inc.
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Component Remove and Replace
12.0 Remove and Replace Fuel
Filter
12.3 Fuel Filter Element Replacement
Procedure
• Part Number 1449383 for Coalescing Filter - Element
and O-Ring
12.1 Fuel Filter Access Procedure
The fuel filter can be accessed by opening the maintenance
access door. Before opening the filter for maintenance, the
filter must be isolated and its pressure relieved.
1.
Follow the Filter Access Procedure.
2.
Remove the filter bowl (it is threaded into the filter
housing and equipped with wrench flats).
1.
3.
Empty and clean the bowl.
4.
Grasp the filter element and pull it downward to
remove. Install the new filter element by pressing it into
place.
Isolate the filter by closing the shut-off valve on the
front panel of the fuel module. This blocks the flow of
fuel from the storage tanks.
2.
Open the purge valve to relieve remaining pressure in
the filter.
3.
Check the high pressure gauge to determine if the
pressure has been relieved (it should read “0”). The
filter can now be safely opened for maintenance.
Purge Valve
Filter Element
WARNING
Failure to follow the Filter Access Procedure
may cause serious injury or death.
12.2 Fuel Filter Drain Procedure
Purge Valve
Filter Bowl
6
5.
Install a new O-ring (supplied with the filter element) in
the housing groove.
O-Ring
Drain Port
1.
Follow the Filter Access Procedure.
6.
2.
To drain the filter, locate the plugged drain port in the
bottom of the filter bowl. Remove this plug to drain
accumulated liquid from the filter.
Replace the filter bowl in the filter housing and torque
to 40 ft.-lbs.
7.
Check that the purge valve is closed.
8.
Slowly open the shut-off valve.
3.
Replace the drain plug and torque to 20 ft.-lbs.
9.
4.
Confirm the purge valve is closed.
Check the high pressure gauge to determine fuel
pressure has been restored.
5.
Slowly open the shut-off valve.
6.
Check the high pressure gauge to determine if the fuel
pressure has been restored.
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Component Remove and Replace
13.0 Remove and Replace Low
and High Pressure Lines
To remove pressure from the fuel lines, start by turning the
valves on each tank to the OFF position. This will stop more
fuel from entering the lines to the engine.
Run the engine until it “dies.”
Attempt to start the vehicle again. If it starts, let it run until it
stalls again.
Repeat the step until the vehicle no longer starts. See
Depressurizing the CNG Fuel System in this manual for
more information.
Use proper hand tools (wrenches) to disconnect the fuel
lines from the tanks and/or CNG system.
13.1 High Pressure Line Identification
Tags
High pressure lines have high pressure line identification
tags placed every 24 inches on lines that are longer than 30
inches. Look for the tags before performing maintenance on
or near high pressure lines.
6
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Troubleshooting
Table of Contents
1.0 TROUBLESHOOTING CHART.......................................................................................................................................... 7-2
7
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Troubleshooting
1.0 Troubleshooting Chart
Problem
Probable Cause
Action
O-rings frozen due to gas expansion.
1.
Wait for receptacles to warm up
to ambient temperature and see if
leak persists.
Debris in fill receptacle.
1.
2.
Depressurize fill manifold.
Remove receptacle from the
3.
4.
5.
manifold.
Inspect for blockage or damage.
Reinstall or replace as needed.
Test for leaks.
After disconnecting fuel nozzle, fuel
flows out of the fill receptacle.
Check valve damaged.
1.
Follow steps above for the check
valve.
The main shutoff valve does not isolate
fuel – engine continues to run even
when valves have been turned to the
OFF position.
Valve seats are worn or debris is not
allowing the valve to fully.
1.
2.
3.
4.
Depressurize system.
Remove the main shutoff valve.
Replace valve seats per valve
manufacturer instructions or
replace the valve.
Test for leaks.
Too much pressure coming out of the
regulator (should be approximately 125
psi).
Regulator not working properly.
1.
2.
Depressurize system.
Remove and replace the regulator.
Not enough pressure coming out of the
regulator (should be approximately 125
psi).
High pressure or low pressure filter is
clogged.
1.
Replace filter element.
7
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© 2016 McNeilus Truck and Manufacturing, Inc.
Index
C
CNG Component Remove and Replace
Connecting the Fuel Module Door Interlock.......................................................................................................................... 6-9
Depressurizing the CNG Fuel System................................................................................................................................... 6-3
Remove and Replace Fill Receptacles................................................................................................................................ 6-10
Remove and Replace Fuel Module....................................................................................................................................... 6-4
Fuel Module Installation................................................................................................................................................. 6-8
Fuel Module Upper and Lower Covers.......................................................................................................................... 6-7
Remove and Replace Fuel Regulator................................................................................................................................. 6-18
Remove and Replace Low Pressure Solenoid Assembly.................................................................................................... 6-11
Remove and Replace Signal Conditioner............................................................................................................................ 6-16
Remove and Replace Solenoid Coil.................................................................................................................................... 6-14
Remove and Replace Transducer....................................................................................................................................... 6-15
CNG Inspection........................................................................................................................................................................ 5-3
CNG System Inspection........................................................................................................................................................ 5-3
Detailed Visual Inspection..................................................................................................................................................... 5-3
End of Service Life of a Tank................................................................................................................................................. 5-3
Fitting Leak Inspection........................................................................................................................................................... 5-3
General Visual Inspection...................................................................................................................................................... 5-3
Mounting Bracket Inspection................................................................................................................................................. 5-3
Connecting the Fuel Module Door Interlock............................................................................................................................. 6-9
D
Defueling the CNG Tanks Procedure....................................................................................................................................... 4-3
Defueling Requirements........................................................................................................................................................ 4-3
Grounding Information........................................................................................................................................................... 4-4
Identify Your Fuel Management Module Box......................................................................................................................... 4-4
Install a Defueling Three-Way Valve to the Fuel Box (MA10 Only)....................................................................................... 4-5
Receptacle Defueling Procedure Set-Up............................................................................................................................... 4-5
Vehicle to Vehicle Defueling Procedure Set-Up.................................................................................................................... 4-5
Depressurizing the CNG Fuel System..................................................................................................................................... 6-3
F
Fire and Explosion Hazards..................................................................................................................................................... 2-9
Fuel Control Module Components............................................................................................................................................ 3-3
Coalescing Filter.................................................................................................................................................................... 3-4
Fueling Receptacle................................................................................................................................................................ 3-4
High Pressure Gauge............................................................................................................................................................ 3-3
Low Pressure Gauge............................................................................................................................................................. 3-3
Manual Shut-Off Valve........................................................................................................................................................... 3-3
Pressure Regulator................................................................................................................................................................ 3-4
Pressure Sensor.................................................................................................................................................................... 3-4
© 2016 McNeilus Truck and Manufacturing, Inc.
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8
Index
Purge Valve........................................................................................................................................................................... 3-4
Remote Fueling Receptacle.................................................................................................................................................. 3-5
Fueling Procedure.................................................................................................................................................................... 4-3
Fuel Storage Pod..................................................................................................................................................................... 3-5
Pressure Relief Devices (PRD)............................................................................................................................................. 3-5
Tank Manual Fuel Shut-Off Valves........................................................................................................................................ 3-5
G
Glossary................................................................................................................................................................................... 1-4
I
Important Safety Information.................................................................................................................................................... 2-3
M
Methane Detection/Alarm System (Optional)......................................................................................................................... 2-10
P
PRD Vent Locations and Directions......................................................................................................................................... 2-8
Preventive Maintenance........................................................................................................................................................... 5-4
Before Performing Maintenance............................................................................................................................................ 5-4
Maintenance Schedule.......................................................................................................................................................... 5-5
R
Remove and Replace Fill Receptacles.................................................................................................................................. 6-10
Remove and Replace Fuel Module.......................................................................................................................................... 6-4
Remove and Replace Fuel Regulator.................................................................................................................................... 6-18
Remove and Replace Low and High Pressure Lines............................................................................................................. 6-25
High Pressure Line Identification Tags................................................................................................................................ 6-25
Remove and Replace Low Pressure Solenoid Assembly...................................................................................................... 6-11
Remove and Replace Signal Conditioner.............................................................................................................................. 6-16
Remove and Replace Solenoid Coil....................................................................................................................................... 6-14
Remove and Replace Transducer.......................................................................................................................................... 6-15
S
8
Safety Decals........................................................................................................................................................................... 2-5
Safety Notices.......................................................................................................................................................................... 2-3
T
Troubleshooting Chart.............................................................................................................................................................. 7-2
V
Vehicle Fueling......................................................................................................................................................................... 3-6
Filling Standards.................................................................................................................................................................... 3-7
Overpressuring Standards..................................................................................................................................................... 3-7
Vehicle Fueling Through Remote Receptacles...................................................................................................................... 3-6
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