Heating Line Product Guide
Ignition Controls Section
Product Bulletin
Issue Date
435.0
G76x
0600
G76x Direct Spark Ignition Controls
The G76x family of controls is designed for direct main
burner ignition and supervision. The G76x is approved
for ignition of natural gas, Liquefied Petroleum (LP)
gas, manufactured gas, mixed gas, or LP gas-air
mixtures.
Figure 1: G76x Direct Spark Ignition Controls
Features and Benefits
❑ Microprocessor-based
Provides precise timing and sequencing
functions
❑ Multiple Trial for Ignition
Offers selectability of timing functions that will
best suit the appliance
❑ Multiple Trials (Optional)
Increases opportunity for main burner ignition
❑ Automatic Recycle
Eliminates nuisance lockouts by restarting the
ignition system (after a predetermined delay)
if pilot flame is not proven within the
trial-for-ignition time
❑ Optional Light-Emitting
Reduces troubleshooting time by visually
informing service technicians of current status
Design
and Prepurge Timings
(Optional)
(Optional)
Diode (LED)
© 2000 Johnson Controls, Inc.
Code No. LIT-4350420
1
www.johnsoncontrols.com
A pplication Requirements
S equence of Operation
O perating Mode Definitions
The control is energized on a call for heat from the
system thermostat. (Models with an optional LED will
turn on the LED [steady on] until the call for heat is
satisfied.) If the control is equipped with the optional
prepurge, the control will delay for the time selected
before initiating a trial for ignition. During the trial for
ignition, the control attempts to light the main burner by
simultaneously energizing the main gas valve and
supplying a continuous spark at the igniter electrode. If
the optional prepurge is not selected, then the trial for
ignition begins within one second after the call for heat.
The spark is deactivated immediately following the trial
for ignition.
Following are the application requirements of the G76x
control.
•
The G76x can be used on gas-fired equipment
with a maximum firing rate of 117 kW
(400,000 Btu/hr). Any application greater than
117 kW (400,000 Btu/hr) must have written
approval in advance from the Johnson Controls
Heating Products Engineering Department.
•
All G76x applications must use a redundant gas
valve system where the main valve seats are in
series and open simultaneous for direct spark
burner ignition.
The following definitions describe operating conditions:
Prepurge: Initial time delay between thermostat
●
contact closure and trial for ignition.
Trial for Ignition: Period during which the main
●
valve and spark are energized in an attempt to
ignite gas at the main burner. The control attempts
to prove flame at the main burner within the
trial-for-ignition time.
Run: Main gas valve remains energized and the
●
spark is turned off after successful ignition.
100% Shutoff: For controls with automatic recycle,
●
main gas did not ignite within the trial-for-ignition
time. The control de-energizes the spark circuit
and main valve.
Automatic Recycle: If 100% shutoff occurs, the
●
control delays for a specific recycle delay period
before beginning another trial for ignition. (Models
with recycle only.)
Interpurge: Period between trials for ignition when
●
both the gas valve and spark are deactivated to
allow unburned gas to escape before the next trial.
Interpurge occurs between unsuccessful trials on a
multi-trial control or after a loss of proven flame
(flameout).
Ignition Lockout: Main gas did not ignite within the
●
final trial-for-ignition time. Open the thermostat
contacts for 30 seconds, then close to restart the
sequence of operation. (Models with an optional
LED will flash the LED to indicate ignition lockout.)
Flameout: Loss of proven flame.
●
Hard Lockout: The control detected a fault. Open
●
the thermostat contacts for 30 seconds, then close
to restart the sequence of operation. (Models with
an optional LED will turn off the LED to indicate a
hard lockout.)
2
G76x Direct Spark Ignition Controls Product Bulletin
Figure 2 illustrates the sequence of operation of the
G76x control.
Under normal conditions, the main burner gas ignites
within the trial-for-ignition time. If the control senses
main burner flame by the end of the trial, the control
proceeds to a run condition. During the run state, the
control energizes the main valve until the call for heat
ends, or until a flameout occurs. If main burner flame
is not sensed by the end of the trial-for-ignition time,
the control may:
•
proceed to a 30-second interpurge followed by
another trial (three trial models whose first two
trials produced no flame)
•
proceed to a lockout (no automatic recycle models
whose final trial produced no flame)
•
proceed to a recycle delay period followed by
another trial (automatic recycle models whose final
trial produced no flame)
If the main burner flame extinguishes during the run
state, the control de-energizes the main gas valve for
an interpurge of 30 seconds. After this period, another
trial for ignition is initiated. If this flameout cycle
repeats for a total of 16 times (main burner flame
established, then lost), the control will:
•
Enter the lockout mode if the control is a G760.
The thermostat contacts must be opened for
30 seconds and then closed to escape the lockout
condition.
•
Enter the 100% shutoff mode and recycle period
(5 minute recycle delay for the G765 and
60 minute recycle delay for the G766) before
beginning another trial for ignition, starting with
prepurge.
Start
Flame present when
not expected
Detected fault
Thermostat
call for heat
No
Flame
present for
30 seconds?
Hard Lockout
(optional LED
turns off)
Yes
Prepurge
Trial for
ignition
Main valve
Yes
flame sensed?
Run
No
Interpurge
No
Yes
Maximum
number of trials
attempted?
Flameout?
Thermostat
calling for heat?
Yes
Yes
Ignition Lockout
(optional LED
flashes)
No
No
Control
with ignition
recycle?
Yes
Yes
Sixteenth
flameout?
No
De-energize
control and valves
No
End
Recycle delay
period
Figure 2: Sequence of Operation
G76x Direct Spark Ignition Controls Product Bulletin
3
M ounting
Choose a location that provides the shortest, direct
cable route to the spark igniter/flame sensor assembly.
Easy access to the terminals is desired for wiring and
servicing.
8
0.31
56
2.22
The control may be mounted in any position. Refer to
Figure 3 for mounting dimensions and Figure 4 for
wiring diagram.
1
58
2.28
6 Spade Terminals
0.25
1
Add 13 mm (0.50 in.) for
Rajah type connector.
78
3.06
34
1.33
6
0.22
GROUND
5
108
4.25
116
4.57
THS 2
P.V. 1
M.V. 3
SENSE 4
6
0.22
20
0.77
Two Holes
4.1 for No. 8 Machine
0.162 or No. 6 Sheet Metal
Mounting Screws
67
2.63
Figure 3: Mounting Dimensions, mm (in.)
4
120
4.70
G76x Direct Spark Ignition Controls Product Bulletin
51
2.00
W iring Diagram
Spark Electrode/
Sensor Assembly
Main Burner
Ground
GROUND
5
LED
THS 2
M.V. 3
SENSE 4
G76x Ignition Control
Main
Valve
Main
Valve
Power
Supply
Limits in
Thermostat
Line Only
Thermostat
Transformer
Figure 4: Wiring Diagram for G76x Ignition Control
G76x Direct Spark Ignition Controls Product Bulletin
5
O rdering Information
G 7 6 _ _ _ _ - _ _
Customer-specific Requirements
(i.e., LED, Spark Transformer Type,
Case Temperature Rating, Special Label,
Miswire, Alarm Contact, Flame Failure
Response Time, Spike Tip Bore, etc.)
Letter
Prepurge
Time
Interpurge
Time
A=
C=
D=
30 seconds
15 seconds
0 second
30 seconds
30 seconds
30 seconds
Letter
A=
B=
C=
D=
Letter
A=
B=
Number
0=
5=
6=
Note:
Trial-for-Ignition
Time
4 seconds
6 seconds
8 seconds
10 seconds
Number of Trials
1
3
Recycle Time
No Recycle
5 Minutes
60 Minutes
Timings listed are for 60 Hz operation. Timings increase by 20% under 50 Hz operation.
The presence of a particular construction in this information does not guarantee its availability.
Consult Johnson Controls for available constructions.
Figure 5: Ordering Matrix
6
G76x Direct Spark Ignition Controls Product Bulletin
Notes
G76x Direct Spark Ignition Controls Product Bulletin
7
S pecifications
Product
Ignition Type
Ignition Source
High Voltage Cable
Maximum Length
G760/G765/G766 Direct Spark Ignition Control
Direct
High voltage spark, capacitive discharge
1,220 mm (48 in.)
Flame Sense Cable
Maximum Length
1,220 mm (48 in.)
Flame Detection Means
Flame rectification
Flame Detection Types
Remote sensing
Minimum Flame Current
0.3 microampere
Flame Failure Response
Time
0.8 second maximum
Spark Gap
Ignition Trials
Ignition Trial Times
Prepurge Times
Interpurge Times
Power Requirements
Contact Ratings
Ambient Operating and
Storage Temperature
Humidity
Wiring Connections
Types of Gas
Packaging
Bulk Pack Quantity
Bulk Pack Weight
Agency Listing
Specification Standards
2.5 mm (0.1 in.) nominal
1 or 3
4, 6, 8, or 10 seconds*
0, 15, or 30 seconds*
30 seconds* (3 trial models only)
Control:
24 VAC, 50/60 Hz, nominal
Operation Current: 0.2A nominal + main valve
Main Valve:
2A continuous, 5A inrush
-40 to 70°C (-40 to 160°F) standard models
-40 to 80°C (-40 to 175°F) high temperature models
95% RH non-condensing
Spark:
Control:
Spike, Rajah, or 6.35 mm (1/4 in.) male spade
6.35 mm (1/4 in.) male spade (4.76 mm [3/16 in.] male spade optional)
Natural, Liquefied Petroleum (LP), manufactured, mixed, or LP gas-air mixture
Bulk pack supplied to original equipment manufacturer (individual pack optional)
50
15 kg (33 lb)
CSA (AGA/CGA) Certificate Number 164933-1079185
Australian Gas Certificate Number 4524 (G760 models only)
ANSI Standard Z21.20, Z21.20a, Z21.20b
CAN/CSA-C22.2 No. 199
*Timings listed are for 60 Hz operation. Timings increase by 20% under 50 Hz operation.
The performance specifications are nominal and conform to acceptable industry standards. For application at conditions beyond
these specifications, consult the local Johnson Controls office. Johnson Controls, Inc. shall not be liable for damages resulting from
misapplication or misuse of its products.
Refer to the G76x Series Technical Bulletin (LIT-121245) for necessary information on the installation, use, and servicing of this product.
Controls Group
507 E. Michigan Street
P.O. Box 423
Milwaukee, WI 53201
8
G76x Direct Spark Ignition Controls Product Bulletin
www.johnsoncontrols.com
FAN 435.0
Heating Line Product Guide
Printed in U.S.A.