INSTRUCTION MANUAL
XDF
MONOBLOC INDOOR AIR CONDITIONING UNITS
DOWN FLOW
XDF 0221
XDF 0281
INSTRUCTION MANUAL
GB
Monobloc downflow Units - XDF0221, XDF0281 - Rev 1.0. - Date: 01-07-1999 EN
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INSTRUCTION MANUAL
XDF
Before installing or carrying out any operation on the unit, carefully read the instructions and safety
regulations in this manual and on the notices on the unit.
UNIFLAIR ITALIA S.r.l.
Via dell’industria, 10
35020 BRUGINE (Padova) Italy
Tel. +39 (0)49 9713211
Fax +39 (0)49 5806906
Internet: www.uniflair.com
e-mail: info@uniflair.com
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Monobloc downflow Units - XDF0221, XDF0281 - Rev 1.0. - Date: 01-07-1999 EN
INSTRUCTION MANUAL
XDF
Index
Page
Symbols used in this manual
Important warning
4
5
GENERAL DESCRIPTION
Documentation enclosed with the unit
Description of the unit and intended use
Description of main components
Accessories
Free-cooling
Access to main components
Data plate
6
6
6
7
8
8
10
11
GUIDE TO INSTALLATION
First steps
Handling and movement
Dimensions and weights
Positioning the unit
Air distribution
Air duct plenum
Condensate drain connections
Electrical connections
Recommended sizes of power supply cables and line fuses (mod. XDF0221-0281)
12
12
13
13
14
15
16
18
19
20
START-UP AND TESTING
Remote control
Start-up procedure
21
21
21
FUNCTION & REGULATION
Microprocessor control
Management of two units
Measurement and alarm devices
Regulation of condensation pressure
Setting the regulation and safety devices
Setting the airflow sensor
Setting the dirty filter sensor
Setting the humidity sensor
22
22
23
24
25
25
26
26
26
TECHNICAL DATA
General characteristics
Electrical characteristics (Models XDF 0221 - 0281)
27
27
28
Monobloc downflow Units - XDF0221, XDF0281 - Rev 1.0. - Date: 01-07-1999 EN
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INSTRUCTION MANUAL
XDF
MAINTENANCE
Regular checks
Cleaning or changing the air filter
Cleaning the air-cooled condenser
Damper maintenance – changing the motor
Changing the electrical heating element
Cleaning and changing the condensate drain tube
Adjusting the refrigerant charge
29
29
29
30
30
31
31
31
PROBLEM SOLVING
Temperature control
Humidity control
Ventilation
Refrigerant circuit
Compressors
Electric heaters
Free cooling
32
32
32
33
34
36
36
37
IMPORTANT: the description of the Control System and the operating logic of the unit are given
in the mP20W Control System instruction manual.
SYMBOLS
SYMBOL
MEANING
SYMBOL
MEANING
DANGER
MOVING COMPONENTS
IMPORTANT WARNING
HOT SURFACE
BURNING
–
RISK
OF
LIVE COMPONENTS – RISK OF
ELECTRIC SHOCK
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Monobloc downflow Units - XDF0221, XDF0281 - Rev 1.0. - Date: 01-07-1999 EN
INSTRUCTION MANUAL
XDF
This unit has been subjected to risk analysis under EC Directive 98/37/CEE (89/392/CEE): it is built to perform the
functions for which it was designed without risk as long as the installation, operation and maintenance of the
unit are all carried out according to the instructions in this manual and on the labels on the unit.
The risks which are particularly important for the safety of the user are marked with the danger symbol:
IMPORTANT WARNINGS
This unit contains refrigerant circuits under pressure, live electrical components, hot surfaces, sharp edges (e.g. the
coil) and rotating devices (e.g. fans). Before opening the unit, disconnect it from the electrical power supply.
All service and maintenance operations must be performed when the unit is off and must be done by
qualified and experienced personnel who are aware of the necessary precautions.
In any case, all safety legislation of the installation location must be followed.
In the event of fire, water and other conductive substances must not be used to put out the fire near live electrical
components. This warning must be displayed on notices in the unit installation location.
If the refrigerants used come into contact with fire they decompose, forming acids and other irritants. The smell of
these substances, even at concentrations below danger levels, gives enough warning to allow evacuation of the
area at risk.
Make sure that the power supply voltage corresponds to the value shown on the data plate.
Monobloc downflow Units - XDF0221, XDF0281 - Rev 1.0. - Date: 01-07-1999 EN
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INSTRUCTION MANUAL
XDF
X
D
F
028
1
Family
Unit
type
Function
mode
Model
Number of
Compressors
D: Downflow
F: mech. cooling
+ free cooling
GENERAL DESCRIPTION
DOCUMENTATION ENCLOSED WITH THE UNIT
Every unit is supplied complete with the following documents:
• Unit instruction manual
• Microprocessor control instruction manual
• Electrical diagrams
• Spare parts list
• CE declaration listing the directives and norms to which the unit conforms
• Guarantee certificate
UNIT DESCRIPTION AND INTENDED USE
The XDF is an autonomous air-cooled downflow monobloc unit designed for the air conditioning of telephone
exchanges and other technological applications.
The unit is pre-charged and tested in the factory and has its own built-in condenser. Installation consists of simply
connecting the unit to the electrical power supply, to the condensate drain and to the air ducting system.
All essential components can be inspected and removed from the front: in multiple installations units can therefore
be fitted very close together.
ACTIVE SAFETY
The control system provides monitoring and prevention functions via:
• Function status indication
• Continuous reading and display of the temperature measured by the sensors
• Indication of fault and alarm situations
• Automatic stopping of unit components in the event of risk
• Compressor management to reduce compressor start-up frequency.
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Monobloc downflow Units - XDF0221, XDF0281 - Rev 1.0. - Date: 01-07-1999 EN
INSTRUCTION MANUAL
XDF
PASSIVE SAFETY
The essential functions of the units are protected against faults and potentially dangerous conditions by the control
system which includes:
• High and low-pressure pressostats to protect the refrigerant circuit (HP with manual re-set)
• Low airflow differential pressostat
• Safety thermostat on units with electric heater
• Compressor electric motor protection
PERSONAL SAFETY
The design and wiring of Uniflair air conditioning units conform to IEC electrical norms. The electrical panels are
equipped with an auxiliary 24V circuit and include individual short circuit protection using automatic circuit breakers.
FUNCTION LIMITS
T room
Only if the condenser is fitted with the
RVC/e speed regulator
T i = 40 °C
T i = 35 °C
T i = 16 °C
T external
T e = 20 °C
T e = 43 °C
T e = 47 °C
DESCRIPTION OF MAIN COMPONENTS
Self-supporting frame in 1.2mm galvanised steel with RAL7021 dark grey epoxy powder paint
External panels in 1.2mm galvanised steel with RAL9001 cream-coloured epoxy powder paint and internally lined
in self-extinguishing abrasion-resistant sound and heat insulation material.
FILTER in self-extinguishing material with EU2 efficiency (doc. Eurovent 4-5) fitted in rigid metal frame.
Double inlet CENTRIFUGAL FAN(S) in galvanised steel keyed directly to the motor shaft.
AIRFLOW SENSOR for activating an alarm if there is insufficient airflow.
COOLING COIL with large frontal area manufactured in copper tubing mechanically expanded into aluminium fins,
stainless steel tray with flexible condensate drain tube.
ELECTRIC RE-HEAT (optional) with finned aluminium elements and safety thermostat for cutting off the power
supply and activating the alarm in the event of overheating..
ELECTRICAL PANEL housed in a compartment isolated from the airflow and which conforms to norms 73/23/CEE
- 89/336/CEE with:
• auxiliary 24V transformer
• main switch with door locking mechanism
• magnetothermal protection
• contactors
Monobloc downflow Units - XDF0221, XDF0281 - Rev 1.0. - Date: 01-07-1999 EN
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INSTRUCTION MANUAL
XDF
HERMETIC SCROLL COMPRESSORS with high energy efficiency, low noise levels and built-in thermal protection
FREE COOLING SYSTEM with motorised damper which enables the introduction of fresh air for cooling
REFRIGERANT CIRCUIT including:
• filter drier and flow sight glass
• thermostatic expansion valve
• high and low-pressure pressostats (HP with manual reset)
mPW MICROPROCESSOR CONTROL: includes room, outdoor and mixed temperature sensors
CONDENSER FAN VARIABLE-SPEED CONTROL (optional)
ACCESSORIES
The following optional accessories can be added to the basic version of the unit:
USER TERMINAL for the setting and display of unit function parameters
FLOOR STAND (for mounting on access floor) with variable height (+/-25mm), min. height 200mm, complete with
vibration-absorbing feet.
BLOCKED AIR FILTER ALARM SENSOR consisting of a dirty filter monitoring pressostat
CLOCK CIRCUIT for the management of time and date events
RS422 / RS485 SERIAL OUTPUT for the transmission of data to a centralised supervision system
DOUBLE ELECTRICAL POWER SUPPLY for normal functioning with mains power and with emergency UPS for
the fan, control and external air damper.
DOUBLE ELECTRICAL POWER SUPPLY including emergency 48V DC with con positivo a massa
CONDENSATION DRAIN PUMP to drain condensation when the gravity system cannot be used
LAN BOARD for the local network connection of two or more units;
TEMPERATURE AND HUMIDITY SENSOR (in place of standard temperature-only sensor)
FLOODING SENSOR
EU4 high-efficiency filter
R407C REFRIGERANT
FREE COOLING SYSTEM
The free cooling cycle consists of the introduction into the room of fresh air when this is sufficiently cold to absorb
the thermal load of the room. The unit is fitted with a butterfly damper and two air intakes:
• recycled air intake (on right hand diagram)
• external air intake (on left hand diagram).
A. NORMAL FUNCTION (fig. 1a)
During normal function the damper (S) is positioned to take in air only from the room (arrow on the right), closing
the external air intake.
The air is filtered (F), cooled and dehumidified in the cooling coil (E) and returned to the room by the fan (VE).
Cooling is via the cooling cycle (starting the compressor).
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Monobloc downflow Units - XDF0221, XDF0281 - Rev 1.0. - Date: 01-07-1999 EN
INSTRUCTION MANUAL
XDF
B. FREE COOLING (fig. 1b)
As soon as the external air is of a low enough temperature to maintain the temperature in the room at the desired
level, the damper (S) changes position, delivering fresh air into the room instead of recycled. Air delivery (in the
same quantity as that taken in) can be performed by the condenser fan (VC) if the intake/output of condensation air
is ducted or directly via the condensation air output with unrestricted delivery of condensation circuit air.
During free cooling function, the compressor (CP) is off.
C. MODULATING FUNCTION (fig. 1c)
When the outside temperature falls further, the introduction of 100% external air would cause excessive cooling.
The control system therefore changes the position of the damper to mix fresh and recycled air to maintain the
temperature in the room at the required level.
In any case, the temperature of the air taken in is maintained above a pre-set minimum.
MINIMUM QUANTITY OF FRESH AIR
It is possible to pre-set a minimum opening position on the damper to allow the introduction of a proportion of fresh
air in any operating mode.
VC
S
F
E
CP
VE
(a)
(b)
(c)
Fig. 1
INTELLIGENT FREE-COOLING
This is an exclusive system which gives dynamic control of the energy-saving phase, maximising the performance
of this function at all times. The result is the ability to provide much greater energy saving (and therefore economy
of operation) than the common fixed-point free-cooling systems.
The microprocessor compares the thermal load present at that moment in the air conditioned environment with the
outside temperature, calculating the optimum temperature at which to start free-cooling.
In this way the temperature at which free-cooling starts is not fixed but changes to adapt to the load conditions
present at that moment in the air conditioned environment
If required, fixed point or fixed differential free-cooling cycles can also be activated; this type of function does not
consider the heat load in the room and activates free-cooling when the outside temperature falls below a pre-set
fixed level.
Monobloc downflow Units - XDF0221, XDF0281 - Rev 1.0. - Date: 01-07-1999 EN
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INSTRUCTION MANUAL
XDF
ACCESS TO MAIN COMPONENTS
The unit is accessible on all sides by removing the relevant panels.
Important: before opening the unit disconnect the power supply and wait for the fans to stop.
VC
A
F
B
IG
C
S
CP
Fig. 2
TOP FRONT PANEL (A)
The panel is hinged at the base and fixed with two screws; to remove it:
- undo the screws
- pull the top of the panel forwards
- lift the panel to free from the base
This gives access to the condensing section (centrifugal fan and finned coil) and to the free-cooling damper.
ELECTRICAL PANEL COVER (B)
Panel (B) is hinged at the base and can be opened only after the IG general switch is turned off (position O). Turn
the two screws ¼ turn to release the top of the panel; push down and turn the screws to close it. Opening this panel
gives access to the air filters.
LOWER FRONT PANEL (C)
Opening this panel gives access to all components of the unit but stops it functioning because the FS pressostat
intervenes.
The panel is slotted into the base of the unit and fastened to the front of the unit with 1 or 2 screws. To remove the
panel:
1. turn the screws 1/4 turn;
2. pull the top edge of the panel forwards;
3. lift the panel up to remove it.
To replace the panel, follow the instructions in reverse
Opening this panel gives access to the evaporator coil, filter drier, sight glass, thermostatic valve, compressor, electric
heating element and the HP and LP pressostats.
SIDE PANEL (S)
Access OT the damper motor is via the side panel shown in the diagram.
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Monobloc downflow Units - XDF0221, XDF0281 - Rev 1.0. - Date: 01-07-1999 EN
INSTRUCTION MANUAL
XDF
DATA PLATE
The data plate is in the electrical panel housing and shows:
- Unit model and serial number
- Power supply (voltage, number of phases and frequency)
- Power absorption of the unit and of the main components
- Current absorption of the unit and of the main components: OA (Operating current), FLA (Full load current) and
LRA (Locked rotor current)
- Setting values of the refrigerant circuit pressostats (high and low pressure) and of the other regulation and safety
devices
- Refrigerant type and refrigerant circuit charge in kg.
MODEL
SERIAL No.
POWER SUPPLY VOLTAGE
ELECTRICAL CURRENT
OA
FLA
LRA
KW TOTALI
SETTING OF SAFETY DEVICES
REFRIGERANT
Fig. 3
Monobloc downflow Units - XDF0221, XDF0281 - Rev 1.0. - Date: 01-07-1999 EN
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INSTRUCTION MANUAL
XDF
INSTALLATION GUIDE
FIRST STEPS
Before installing the unit, take the following steps:
1. Make the holes for fresh air intake and condensation air expulsion in the walls of the room
2. Use rubber seals to ensure airtight connections between the intake/expulsion holes and the unit, ideally 1820mm thick closed-cell self-adhesive neoprene tape
3. Check that the unit is level; an inclination of more than 0,5° could cause the condensate tray to overflow
4. Use either rigid or flexible pipes to connect the air intake and delivery (see following sections).
HOLE IN THE RAISED FLOORING UNDER THE UNIT
Treated air is delivered into the raised floor cavity and distributed through it into the room.
Before installing the unit a hole must be made in the raised flooring; this must have the dimensions labelled G and
H and the unit must be positioned exactly over the centre. The gap must not be even partially obstructed by
sections of panels, stringers, pipes, etc.; fit an elastic gasket around the base of the unit to avoid the transmission of
noise and vibrations. Fig. E shows the bottom of the unit with main dimensions.
H
mm
G
H
XD* 0221
301
265
XD* 0281
301
265
G
Fig. 4
203.5
345.5
G
H
Ø36 mm
450
145
850
Fig. 5
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Monobloc downflow Units - XDF0221, XDF0281 - Rev 1.0. - Date: 01-07-1999 EN
INSTRUCTION MANUAL
XDF
HOLES FOR AIR DUCTING
Two holes with the dimensions given in fig. 6 must be made in the wall of the room for the expulsion of
condensation air and the intake of fresh air. The air distribution ducts must not be even partially obstructed.
Fig. 7 shows the rear of the unit with main dimensions.
mm XD* 0221 XD* 0281
300
300
E
259
259
F
290
290
M
720
720
L
275
E
40
275
F
E
277
M
F
M
1970
65
L
65
L
1104
850
Fig. 7
Fig. 6
Use rubber seals to ensure airtight connections between the intake/expulsion holes and the unit, ideally 18-20mm
thick closed cell self-adhesive neoprene tape.
NEOPRENE SEAL
Fig. 8
Monobloc downflow Units - XDF0221, XDF0281 - Rev 1.0. - Date: 01-07-1999 EN
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INSTRUCTION MANUAL
XDF
TRANSPORT AND MOVEMENT
The unit should not be turned on its back or upside-down, or exposed to the weather and should be taken as
near as possible to the installation location before removing the cardboard packing and the pallet.
The unit can be lifted:
- with a fork-lift, placing the forks in the appropriate slots of the pallet;
- with straps passed under the unit, making sure that they do not put pressure on the upper rim of the unit.
The unit must be stored, preferably in its packing, under cover and protected from excessive humidity (< 90% R.H.)
and temperature (< 50°C).
The dimensions and weight of the unit with packaging are given below
mm
XDF 0221 XDF 0281
M
N
O
910
2100
510
910
2100
510
kg
220
225
N
O
M
Fig. 9
The symbols applied to the unit’s packaging conform to ISO7000; they are explained in the table below.
SYMBOL
MEANING
FRAGILE: handle with care.
SYMBOL
MEANING
THIS SIDE UP shows
orientation of the unit.
the
PROTECT AGAINST MOISTURE:
the packaged unit must be stored
in a dry place.
TEMPERATURE LIMITS: the unit
must not be stored outside these
limits.
CENTRE OF GRAVITY: shows the
centre of gravity of the packaged
unit.
NO HOOKS: do not use hooks to
lift the packed unit.
KEEP AWAY FROM HEAT: the
unit must be kept away from heat
sources.
DO NOT STACK
RECEIVING THE UNIT
When the unit arrives, check that it is complete and in perfect condition; notify the carrier immediately in writing
of any damage that might have been caused in transit.
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Monobloc downflow Units - XDF0221, XDF0281 - Rev 1.0. - Date: 01-07-1999 EN
INSTRUCTION MANUAL
XDF
DIMENSIONS AND WEIGHTS
C
mm XDF 0221 XDF 0281
850
850
A1
1970
1970
B
450
450
C
700 *
D
100 *
E
195
200
kg
* see section on Working Space
B
E
A1
D
Fig. 10
POSITIONING THE UNIT
XD units are designed for installation inside the air conditioned room; they can be placed directly on the floor.
♦ The unit must be perfectly level with a maximum difference of 5 mm between sides: an inclination could cause
the condensate tray to overflow.
♦ IMPORTANT: the unit must be installed in a closed environment and protected from adverse conditions.
Do not install the unit less than 200 metres from the sea or near areas with sulphurous springs. Make sure that
the unit cannot take in air which contains vapours of inflammable or greasy substances.
♦ Fit an elastic gasket around the base of the unit to avoid the transmission of noise and vibrations.
♦ The air flow taken in by the fans via the condenser coil must not be obstructed in order not to reduce the
efficiency of the unit and to avoid the unit stopping because of the intervention of the compressor’s safety
functions.
Monobloc downflow Units - XDF0221, XDF0281 - Rev 1.0. - Date: 01-07-1999 EN
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INSTRUCTION MANUAL
XDF
SUPPORT FRAME (optional)
A support frame is recommended:
- to enable installation of the unit before the raised floor is installed;
- to absorb mechanical vibrations;
- to facilitate the connection of pipes and cables.
The height of the optional support frame is between 200 and 500mm (shown as X); other heights are available on
request.
To avoid the transmission of vibrations, fit an elastic seal at least 5mm thick between the support frame and the
floor panels; the frame must also be isolated from the floor structure.
.
A1
C1
mm
A1
C1
X
XD* 0221
850
430
XD* 0281
850
430
X = 200 ÷ 500 mm
Fig. 11
WORKING SPACE
To facilitate maintenance, leave at least 700mm free space in front of the unit as shown in the fig. J (point D).
N.B.: Side access may be necessary in the unlikely event that the damper motor needs to be replaced or if the
power supply cables are not passed through the holes in the base of the unit.
AIR DISTRIBUTION
Treated air is delivered into the raised floor cavity and distributed through it into the room. Since the cooling capacity
of the unit depends on the air flow, pay particular attention to:
a) free air flow in the raised floor cavity; the cavity under the raised floor must be at least 200-250 mm high, not
including the thickness of raised floor panels and stringers and free from obstructions, especially near the unit;
b) grilles and holes for air distribution in the room; the air comes out of grilles or holes in the floor; the location
and dimensions of these vents must correspond to the room heat load pattern.
The air velocity out of the raised floor should be between 1 and 2.5 m/s
The total free area (the sum of the sections of the air outlets) necessary for each model is calculated by dividing the
3
total air flow rate (in m /s) by the required airflow velocity (in m/s).
The nominal airflow for each model is given in the technical data section of this manual. The location and
dimensions of the outlets must correspond to the room heat load pattern and to the layout of the units.
IMPORTANT: An insufficient outlet area reduces the airflow and the cooling capacity of the units: keep the
air outlet completely clear.
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Monobloc downflow Units - XDF0221, XDF0281 - Rev 1.0. - Date: 01-07-1999 EN
INSTRUCTION MANUAL
XDF
AIR DUCTING PLENUM (optional)
If flexible tubes are used a rear plenum can be used, positioned as shown below:
Fig. 12
The plenum must be fixed to the unit using the holes provided in the rear panel.
Monobloc downflow Units - XDF0221, XDF0281 - Rev 1.0. - Date: 01-07-1999 EN
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INSTRUCTION MANUAL
XDF
CONNECTING THE CONDENSATE DRAIN
The condensate collection tray is located at the base of the evaporator coil. The condensate drains from the tray via
a flexible tube (included with the unit) on the right hand side of the condensate tray. The end of the tube should be
connected to the building’s waste water system via a rubber or plastic tube with internal diameter 25mm and a
minimum slope of 1%. The optional condensate drain pump can be specified where gravity is not sufficient to drain
the tray.
Piping can enter the unit from the bottom or through the pre-cut holes in the side/rear panels of the base frame (see
diagram).
Pre-cut holes for piping connections
Fig. 13
WATER CONNECTIONS
MODEL
Condensate Drain
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XD* 0221
XD* 0281
Ø 21 mm
Monobloc downflow Units - XDF0221, XDF0281 - Rev 1.0. - Date: 01-07-1999 EN
INSTRUCTION MANUAL
XDF
ELECTRICAL CONNECTIONS
Refer to the electrical diagrams provided in the envelope marked “INSTRUCTIONS”. Correct and
accurate electrical connections, carried out in accordance with best practice and with local regulations,
are extremely important for the prevention of accidents and for ensuring long, trouble-free operation.
ACCESS TO THE ELECTRICAL PANEL
Before working on the electrical parts of the unit, make sure that there is no power supply to the unit and
that the switch on the electrical panel is off (in the “O” position);
CHECKS
Check that the mains voltage corresponds to the nominal data of the unit (voltage, phases, frequency) shown on the
electrical panel and on the electrical diagrams.
Power supply voltage must be within –10% / +6% of the nominal value. In tri-phase units the difference between the
phases must be less than 2%: unit operation with power supplies outside these limits may invalidate the guarantee.
CONNECTION TO THE MAINS
•
Pass the electrical supply cable through the hole in the bottom of the unit. The cable can also be passed
through the sides or back of the base frame after opening the pre-cut holes. See also the table “Recommended
cable sections and line fuses”
•
Take the cable up to the main switch in the electrical panel
•
Fix the ends of the power supply cable to the top terminals of the main switch in the electrical panel and tighten
the screws; the yellow/green earth wire must be connected to its terminal.
L1 L2 L3 N
Q.E.
TR
IG
IM
Fig. 14
Monobloc downflow Units - XDF0221, XDF0281 - Rev 1.0. - Date: 01-07-1999 EN
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INSTRUCTION MANUAL
XDF
UNIT WITH DOUBLE POWER SUPPLY (optional)
XDF units can be fitted with a double power supply:
• main 400V/3N/50Hz line for the:
• compressor
• electric heating element
• condenser fan(s)
• UPS 230V/1/50Hz line for:
• evaporator fan(s)
• damper motor
• mP20 microprocessor circuit and terminal.
Units can also be specified with double power supply with emergency 48V DC line.
RECOMMENDED POWER SUPPLY CABLE SECTIONS AND LINE FUSES
Models XDF 0221 - 0281
MODEL
LINE
FUSES (a)
XDF 0221
4x4+4PE
40A
XDF 0281
4x4+4PE
40A
NOTE (a): back-up protection before the power supply line for per Icc up to 50kA
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Monobloc downflow Units - XDF0221, XDF0281 - Rev 1.0. - Date: 01-07-1999 EN
INSTRUCTION MANUAL
XDF
START-UP AND TESTING
REMOTE CONTROL
(refer to mP20/W microprocessor control instruction manual)
REMOTE ALARM SIGNALLING
The microprocessor control board has the following potential-free contacts for remote alarm signalling:
a. Cumulative addressable; use the keypad to select which alarms to include/exclude
b. compressor
c. fan
d. dirty filter
e. electric heating element.
If the unit is connected to an external control system (e.g. PLC), it can be controlled via potential-free contacts.
The following control modes are possible:
1. Unit ON-OFF remote control: the microprocessor automatically controls all unit functions.
2. ON-OFF which enables/disables:
free-cooling
compressor
electric heating element
3. ON-OFF control of:
evaporator fan
compressor
electric heating element
free-cooling, maintaining intelligent microprocessor logic.
SUPERVISION SYSTEM
A supervision exchanges data with the unit’s microprocessor circuit board via serial cable; an optional serial board
is available for opto-insulated remote control interface with an RS422 / RS485 data transmission network.
START-UP PROCEDURE
Switch on the power supply to the electrical panel:
• Arm the IM automatic switch
• Close the cover of the electrical panel and move the main switch IG to the on position “I”)
• Close the auxiliary switch on the cover of the electrical panel and check that the yellow LED is on.
If the RSF phase sequence control relay intervenes, switch off the power supply to the unit,
swap two power supply phases and begin the start-up procedure again.
Start the unit by pressing the
button on the control terminal; after a short delay the fan will start and the green
LED on the control panel will come on. If there is an alarm shown by the red ALARM LED and the buzzer, consult
the microprocessor control manual.
Monobloc downflow Units - XDF0221, XDF0281 - Rev 1.0. - Date: 01-07-1999 EN
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INSTRUCTION MANUAL
XDF
FUNCTION AND REGULATION
MICROPROCESSOR CONTROL
(see mP20/W instruction manual)
The control system consists of:
• Microprocessor control board in the electrical panel
• Optional user interface terminal
• Room temperature sensor
• External temperature sensor
• Delivery air temperature sensor
• Electrical connection terminals
The microprocessor control board holds the control algorithms and function parameter memory and can therefore
manage unit function autonomously, without the user terminal. This solution - not using any user interface for the
setting of parameters or for the visualisation of data and events - can be used for installations where programming
of functions and/or function parameters needs to be modified very rarely or never (such as non-supervised
installations.
The programming of control parameters and the visualisation of data and events are done using the User Terminal,
which has an LCD display, keypad, LED signals and an alarm buzzer. Once programmed, the circuit board
functions autonomously using the set data held in the memory.
The control board provides the following functions:
• Control of room temperature
• Display of room relative humidity (with optional temperature and humidity sensor)
• Maximum room humidity setting which, when reached, closes the free-cooling damper and forces compressor
start-up (with optional humidity sensor)
• Management of electrical re-heat (optional)
• Management of alarms
• Management of stand-by if two or more units are connected (with LAN board)
• Alarm system with visual and acoustic signals
• Signal contacts for each type of alarm
• Programmable general alarm signal for the signalling of specific selectable alarms
• Programmable automatic re-start after a power failure
• Programmable re-start delay in multiple installations
• Compressor activation control (limits frequency of start-ups)
• Programmable control (remote control or supervision)
• Control of delivery air minimum temperature limit (XDF)
• Control of free-cooling damper position (special units)
• 2 levels of password programming (setting / hardware & software configuration)
• RS422 or RS485 serial output (optional)
• Clock/calendar circuit
• Run hour counter for main components
• Service scheduling with clear information on necessary actions
• Memorisation of last 30 alarms (with date and time if optional clock circuit fitted)
• Detailed display of function mode and active components (with optional user terminal)
• Weekly on/off time bands (with optional clock circuit) for weekdays, pre-holidays, holidays
• Set-back function where the unit is in stand-by but maintains room temperature between two pre-set limits and
relative humidity below a pre-set limit (with optional temperature and humidity sensor).
• Distinct setting of heating and cooling set point
• Override function for the manual control of main components without excluding remote control.
• Optimised control algorithm which constantly monitors the temperature of the room, of the air outside and of the
delivery air for optimised management of both the direct expansion and the intelligent free cooling functions.
Free cooling can therefore start earlier and continue for longer and at higher external temperatures since it
takes into account the thermal load in the room at that moment.
• Advanced free-cooling management of two units with stand-by function to maximise energy saving.
• Immunity to electromagnetic and electrostatic disturbance in accordance with CEE Directive 89/336. Has no
need of external mains filters or capacitors for absorption of disturbance or reduction of charges. Has passed all
tests under EN50082-2 for industrial environments.
22 (37)
Monobloc downflow Units - XDF0221, XDF0281 - Rev 1.0. - Date: 01-07-1999 EN
INSTRUCTION MANUAL
XDF
MANAGEMENT OF TWO UNITS
(See LAN instruction manual)
If two units are installed it is possible to connect the two microprocessor controls electrically in order to
manage the function of the two units without an external management system.
The control circuit manages the following situations:
•
•
•
•
one unit functioning and the other in stand-by
the switching on of the reserve unit if there is an alarm in the functioning unit
the rotation on a time basis of which unit is functioning in order to divide the workload between the two
the switching on of the second unit in the event that a pre-set temperature threshold is exceeded in the air
conditioned environment- This function can be overridden if electrical restrictions mean that both units cannot be
operated at the same time.
If both units have the free-cooling function, in relation to the rise in temperature and/or the thermal load, the function
logic is:
LOW
Free-cooling
1
>> Outside temperature >>
1+2
Mechanical cooling
Stand-By
2
1
2
HIGH
1
1+2
2
N.B. If units are connected in a local network only one user terminal needs to be fitted. This terminal communicates
with the microprocessor circuits in the units in the network
SET-BACK FUNCTION
The set-back function, if activated, ensures that the temperature in the room does not exceed the high/low
thresholds. If readings exceed one of the limits the microprocessor takes control of the unit so that the temperature
returns below the set limit. This function allows the covering of any faults in the external command system.
TIME BANDS
This function, available with the optional clock circuit, enables the setting of automatic start-up and switching off
times of the units (time band function). It is possible to sub-divide the time bands into weekdays, pre-holidays and
holidays.
Monobloc downflow Units - XDF0221, XDF0281 - Rev 1.0. - Date: 01-07-1999 EN
23 (37)
INSTRUCTION MANUAL
XDF
MEASUREMENT AND ALARM DEVICES
The safety and regulation functions of the unit are performed by the microprocessor control.
The unit is equipped with the following temperature, humidity and pressure sensors, as shown in the figure below:
RVC/e.
TSR.
SM.
SE.
ST-STU.
FS.
PFS.
AP-BP.
STE.
SC-SPC.
Modulates condenser fan speed to control condensation pressure (optional)
Electric heating element safety thermostat with re-set button under the coil
Delivery air temperature sensor
External air temperature sensor
Room temperature (or optional temperature and humidity) sensor. The ST sensor is installed in the
unit as shown in the diagram; the STU sensor is supplied with a 3 metre cable and must be
installed in the room.
Air flow sensor (differential pressostat) to detect low airflow and fan function
Dirty filter sensor (differential pressostat)
Fixed setting high / low pressure switches (HP with manual re-set)
Evaporation temperature sensor;
Condensation temperature/pressure sensor.
FS
PFS
ST
SE
TSR
AP
BP
SM
Fig. 15
24 (37)
Monobloc downflow Units - XDF0221, XDF0281 - Rev 1.0. - Date: 01-07-1999 EN
INSTRUCTION MANUAL
XDF
REGULATION OF CONDENSATION PRESSURE
Condensation pressure is controlled by a TRIAC voltage regulator on the condenser fan power supply. The
regulator is optional (see Function Limits) and has the code RVC/e; it is controlled by the microprocessor as a
function of the condensation temperature read by the sensor.
The setting - done on the user terminal - has the following standard values:
V
Maximum speed:
100%
• maximum speed for saturated condensation
temperature of 50°C (corresponding to delivery
pressure of 18,5 bar) with R22
• minimum speed for a saturated condensation
temperature of 35°C (corresponding to a delivery
pressure of 12,7 bar) with R22
• minimum fan power supply voltage (cut-off
voltage) of 15% of mains voltage.
Minimum speed:
15%
As an alternative to the SC temperature sensor it is
possible to use the SPC condensation pressure
sensor.
PROPORTIONAL
BAND
T. MIN (default: 35°C)
T. COND
T. MAX (default: 50°C)
SETTING THE REGULATION AND SAFETY DEVICES
After starting the unit, make the following settings:
- Room temperature: see control manual;
- Room relative humidity: see control manual;
- Dirty filter differential pressostat: see section on Setting the Dirty Filter Sensor.
Check that safety devices are set at the values shown in the table below.
The regulation and safety devices are set in the factory and must not be changed without good reason.
AP
BP
TSR
Description
Intervention
Differential
Re-set
HP Pressostat
LP Pressostat
Heating element safety thermostat
26,5 bar
2,0 bar
320 °C
--1.5 bar
---
Manual reset
3.5 bar
Manual reset
Monobloc downflow Units - XDF0221, XDF0281 - Rev 1.0. - Date: 01-07-1999 EN
25 (37)
INSTRUCTION MANUAL
XDF
SETTING THE AIRFLOW SENSOR
The FS differential pressostat should intervene if the fan is not working (if the unit has one fan only) or if one of the
fans is not working (in the case of multiple fans).
The setting of the airflow differential pressostat is 1.0 mbar (100 Pa). Since the difference in pressure between the
fan intake and delivery depends on the airflow, it is necessary to set the pressostat after installation, making sure
that the contact closes when the fan is in normal operation. To set the pressostat:
• set the fan speed regulator at the required value (see Fan Speed Regulation);
• simulate a fan fault (stop the fan, or one of the fans if multiple); check that the pressostat intervenes
• if the pressostat does not intervene, gradually lower the setting until it does
The FS differential pressostat can be set on a scale from 0.5 to 5.0 mbar (from 50 to 500 Pa).
SETTING THE DIRTY FILTER SENSOR
(optional)
The PFS pressostat must be set as a function of the pressure drop; this depends not only on how dirty the filter is
but also on the airflow and therefore on the setting of the fan speed regulator. The setting must be done when the
filter is clean:
• set the fan speed regulator at the desired value (see Fan Speed Regulation);
• set the pressostat intervention at 1.5 mbar;
• gradually cover the surface of the air filter and check that the pressostat intervenes when the filter is about 5060% covered;
If the pressostat does not intervene, gradually lower its setting; if it cuts in too soon, increase the setting.
SETTING THE HUMIDITY SENSOR (optional)
SHW, ASWH, SFHOOB or similar humidity sensors (available to order on certain unit versions) can be set with the
trimmer on the front of the sensor; it is not necessary to open the casing
SFH - SHW
ADJUSTING
TRIMMER
Fig. 16
Temperature setting is done on the user terminal (see mP20 instruction manual); adjustment is at intervals of 0.1°C;
maximum adjustment is between -9.9°C and +9.9°C
26 (37)
Monobloc downflow Units - XDF0221, XDF0281 - Rev 1.0. - Date: 01-07-1999 EN
INSTRUCTION MANUAL
XDF
TECHNICAL DATA
GENERAL CHARACTERISTICS
These characteristics refer to standard units and may be different for special or modified units.
.
MODELLO
TENSIONE DI ALIMENTAZIONE
POTENZA FRIGORIFERA
Raffreddamento Meccanico
Ambiente a 27 °C- 40%URText=35°C
Resa frigorifera totale
Resa frigorifera sensibile
Raffreddamento in free-cooling
Ambiente a 26 °C- Text=14°C
Sensibile
VENTILATORI CENTRIFUGHI
Portata d’aria nominale
Numero di ventilatori
V/ph/Hz
XDF0221
XDF0281
400/3+N/50
400/3+N/50
MODEL
V/ph/Hz
kW
kW
6.4
5.9
7.1
6.5
kW
kW
kW
9.0
9.0
kW
m³/h
2230
1
2230
1
m³/h
FILTRO DELL’ARIA
Dimensioni filtro EU2 (standard)
Dimensioni filtro EU4 (opzionale)
COMPRESSORE FRIGORIFERO
Tipo
Potenza nominale (ARI standard)
VENTILATORI CONDENSATORE
Portata d’aria nominale
Numero
POWER SUPPLY
COOLING CAPACITY
Mechanical cooling
Room at 27 °C- 40%RH- Text=35°C
Total cooling capacity
Sensible cooling capacity
Free-cooling
Room at 26 °C- Text=14°C
Sensible
CENTRIFUGAL FANS
Nominal airflow
Number of fans
AIR FILTER
kW
m³/h
SCROLL
1.9
SCROLL
2.1
2200
1
2200
1
kW
m³/h
COMPRESSOR
Type
Nominal power (ARI standard)
CONDENSER FANS
Nominal airflow
Number
RISCALDAMENTO ELETTRICO (1)
Numero di stadi
Potenza totale
kW
1
2
1
2
kW
ELECTRICAL RE-HEAT (1)
Number of stages
Total power
DIMENSIONI
Altezza
Larghezza
Profondità
Peso (unità senza imballo)
mm
mm
mm
kg
1970
850
450
195
1970
850
450
200
mm
mm
mm
kg
DIMENSIONS
Height
Width
Depth
Weight (unit without packaging)
(1) Opzionale
Monobloc Down-flow Units - XDF0221, XDF0281 - Rev 1.0. - Date: 01-07-1999 EN
(1) Optional
27 (37)
INSTRUCTION MANUAL
XDF
ELECTRICAL CHARACTERISTICS
Models XDF 0221 - 0281
This table shows power and current absorption of individual electrical components; electric heating elements are
only fitted on T versions.
UNIT COMPONENTS
COMPONENTI DELL’UNITÁ
COMPRESSORE
COMPRESSOR
K
50 Hz
∗ 0221
XD∗
∗ 0281
XD∗
V/ph/Hz
No.
400/3+N/50
400/3+N/50
1
1
2
V/ph/Hz
No.
3.4
4.5
230/1/50
230/1/50
1
1
kW (2) OA (2) FLA
0.72
0.72
Tensione di alimentazione
Numero
Potenza Nominale (2) per elemento ()
Assorbimento nominale (per elemento)
Assorbimento massimo (per elemento)
Corrente di spunto (per elemento)
(2)
3.0
3.9
LRA
V/ph/Hz
No.
kW
OA
FLA
LRA
22.3
31.0
230/1/50
230/1/50
1
1
0.66
0.66
2.9
2.9
-
-
VENTILATORI DEL CONDENSATORE
CONDENSER FANS
CF
∗ 0221
XD∗
∗ 0281
XD∗
kW (2) OA (2) FLA
1.7
2.2
3.2
3.2
VENTILATORI DI RICIRCOLO
RECIRCULATION FANS
RF
LRA
V/ph/Hz
No.
kW
OA
-
230/1/50
230/1/50
1
1
2
2
8.7
8.7
-
V/ph/Hz
No.
kW
OA
FLA
LRA
RESISTENZE ELETTRICHE (opzionali)
ELECTRICAL HEATERS (optional)
EH
Supply Voltage
Number
(2)
Nominal Absorbed Power (each element)
Operating Current (each element)
Full Load Current (each element)
Locked Rotor Current (each element)
kW
A
A
A
(2)
Ambiente: 26°C/40%UR - Test.: 35°C
Room at: 26°C / 40% - Text.: 35°C
The table below lists power and current absorption of the whole unit in various function modes (with tri-phase
models the maximum current is given for one phase). The electric re-heat phase is only present on models with
humidity control and heating elements.
COMPLETE UNITS
UNITÁ COMPLETE
SENZA RESISTENZE
WITHOUT ELECTRIC HEATERS
∗ 0221 C
XD∗
∗ 0281 C
XD∗
K + RF + CF
RAFFREDDAMENTO
MECCANICO
MECHANICAL COOLING
FUS
V/ph/Hz
kW
L1
L2
L3
V/ph/Hz
kW
L1
L2
L3
4
4
40A
40A
400/3+N/50
400/3+N/50
3.1
3.6
9.1
10.0
3.0
3.9
3.0
3.9
400/3+N/50
400/3+N/50
1.4
1.4
6.1
6.1
0
0
0
0
K + RF +
CF + EH
DEUMIDIFIC. & POSTRISC.
ELETTRICO
DEHUMIDIFICATION &
ELECTRIC REHEAT
mm²
FUS
V/ph/Hz
kW
L1
L2
L3
4
4
40A
40A
400/3+N/50
400/3+N/50
5.1
5.6
10.7
11.8
9.1
10.0
9.1
10.0
Tensione di alimentazione
Potenza Nominale (1)
Massima corrente per fase
Cavo di alimentazione consigliati
Fusibili di linea consigliati
28 (37)
CICLO DI FREE-COOLING
FREE-COOLING CYCLE
mm²
CON RESISTENZE
WITH ELECTRIC HEATERS
∗ 0221 T
XD∗
∗ 0281 T
XD∗
CF + RF
V/ph/Hz
kW
L1-L2-L3
mm²
FUS
kW
A
mm²
A
Supply Voltage
Nom. Absorbed Power (1)
Max current per phase
Suggested Power Supply Wiring Section
Suggested Line Fuses
Monobloc Down-flow Units - XDF0221, XDF0281 - Rev 1.0. - Date: 01-07-1999 EN
INSTRUCTION MANUAL
XDF
MAINTENANCE
REGULAR CHECKS
The following maintenance operations should be done regularly:
•
•
•
•
•
•
•
•
•
•
•
check the set values of the control and regulation devices;
check that room conditions on the control panel display are normal;
check normal condensation and evaporation pressures;
check the refrigerant charge; the sight glass should be clear (however the presence of a few bubbles is normal
check the correct function of the external air damper
check normal temperature and noise levels of compressor and fans;
check the air filters; clean or change the filters when the dirty filter alarm comes on;
check the flow of condensate to the drain;
check whether the condenser is dirty, removing any obstructing material with a jet of compressed air or water;
check that all electric terminal connections are tight;
check that power supply voltage is within design limits.
CLEANING AND CHANGING THE AIR FILTER
Inspect the filter cartridge at least once a month and whenever there is a blocked filter alarm:
- turn off main switch IG;
- open the front cover of the electrical panel;
- remove the filter cartridge (F) and then clean with a vacuum cleaner. If the filter is blocked, replace it with an
equivalent model.
F
Fig. 17
Monobloc downflow Units - XDF0221, XDF0281 - Rev 1.0. - Date: 01-07-1999 EN
29 (37)
INSTRUCTION MANUAL
XDF
CLEANING THE AIR-COOLED CONDENSER
If the finned coil of the air-cooled condenser is dirty, remove any obstructing material (leaves, paper, etc.) with a jet
of compressed air.
An optional metal filter (G) can be fitted on the condenser coil intake; to clean it, the upper front panel (A) must be
removed.
G
A
Fig. 19
DAMPER MAINTENANCE – CHANGING THE MOTOR
Check the free flow of air through the damper and the condition of the neoprene rubber, making sure that the edges
form a tight seal
In an emergency (e.g. if the motor breaks) or for maintenance, it is possible to move the damper manually by
opening side access panel S and pressing release switch A.
To take out the motor, undo fixing screws B completely and remove the motor from the damper shaft..
B
A
B
S
Fig. 20
30 (37)
Monobloc downflow Units - XDF0221, XDF0281 - Rev 1.0. - Date: 01-07-1999 EN
INSTRUCTION MANUAL
XDF
CHANGING THE ELECTRIC HEATING ELEMENT
The heating elements are located in front of the finned coil and can be accessed after removing the lower front
panel of the unit.
IMPORTANT: before working on the electric heating element, switch off the power supply by moving the main
switch to the OFF position (O) and wait for the element to cool.
CLEANING AND CHANGING THE CONDENSATE DRAIN TUBE
If necessary, change the condensate drain tube starting from the drain tray under the evaporator coil. To clean the
tube, disconnect it from the tray and use a use a jet of water.
ADJUSTING THE REFRIGERANT CHARGE
The unit’s refrigerant circuit is supplied already charged with R22 or R407C.
Check the type of refrigerant to use on the data plate of the unit and of the compressor.
If necessary, top up the charge using only the refrigerant and oil specified in the unit manual. Drain the refrigerant
circuit completely, making sure that no refrigerant gas leaks into the environment, then create a vacuum in the
circuit. A pressure of less than 100 Pa absolute (0,7 mm Hg) must be maintained in order to evacuate all air and
moisture traces.
Start the compressor and slowly charge the refrigerant circuit via the special valve until the pressure in the line
stabilises and the bubbles in the sight glass disappear. This valve is on the vertical section of piping immediately
downstream of the thermostatic valve.
The charge must be done under room conditions and with a discharge pressure of around 16-18 bar (equivalent to
a saturation temperature of 48°C).
Check that the super-cooling of the liquid at the intake of the thermostatic valve is between 3 and 5°C less than the
condensation temperature reading on the manometer scale and that the superheating of the vapour at the
evaporator output is around 5-8°C.
Oil: the average dilution is around 5% by weight of the refrigerant charge. If it is necessary to add oil, use only the
recommended type below:
Refrigerant
R22 (Mineral oil)
R407C (POE)
Recommended oil
Suniso 3 GS
Texaco WF 32
Fuchs KM
Mobil EAL Arctic 22 CC
ICI EMKARATE RL 32S
Monobloc downflow Units - XDF0221, XDF0281 - Rev 1.0. - Date: 01-07-1999 EN
31 (37)
INSTRUCTION MANUAL
XDF
PROBLEM SOLVING
Identifying and solving problems is made easier by the microprocessor control which, in the event of an alarm:
• activates the alarm relay as well as the red LED and buzzer on the user terminal
• displays an alarm condition on the user terminal
• describes, via the appropriate routine, the nature of the alarm and the possible solution.
If the HP pressostat or electric heater safety thermostat intervene they must be re-set manually using the button on
the device.
Many problems can be caused by loose terminal connections. In the event of an alarm,
check that all wires are securely fixed in the terminals.
If there is a fault, contact the nearest authorised Uniflair Service Centre, giving the nature of the fault and any
probable causes.
Always consult the Microprocessor Control Manual included with the unit - many problems which seem to be faults
are simply a question of incorrect or incomplete programming of the control.
PROBLEM
POSSIBLE CAUSE
CHECK / REMEDY
NO POWER
A) No power to the unit electrical panel Check that power is on and the unit main
switch on the electrical panel is closed.
1) Check that the IM automatic circuit
(The yellow LED on the mP20 board is B) No power to the auxiliary circuit
off).
breaker on the AUX circuit is set.
2) Check the auxiliary circuit 24V fuse; check
the fuse on mP20 board.
THE UNIT DOES NOT WORK
32 (37)
The
message
“ATTENTION: The phase sequence is inverted. Disconnect
INCORRECT PHASE SEQUENCE” the unit from the power supply and swap
over two power supply phases.
appears on the display
If the alarm is shown when the unit is
operating, it is possible that the LP
pressostat has intervened. Check the
pressure of the refrigerant circuit in the
section subject to evaporation pressure.
The control panel does not start the Check that the control panel connectors are
unit.
correctly located in their sockets; see control
panel instruction manual.
Check the control panel for alarms
See the control panel instruction manual
The circuit does not receive the With a remote control system, check that the
function command in remote control contact between terminals 20 and 50 is
closed
mode
Monobloc downflow Units - XDF0221, XDF0281 - Rev 1.0. - Date: 01-07-1999 EN
INSTRUCTION MANUAL
XDF
TEMPERATURE CONTROL
PROBLEM
POSSIBLE CAUSE
CHECK / REMEDY
ROOM TEMPERATURE TOO HIGH
(high room temperature alarm)
The parameter settings on the control
panel are not correct
Lack of air flow.
The compressor does not work when
called by the control panel.
Insufficient compressor output
Check the room temperature setting; see
control panel instruction manual.
See ”Lack Of Air Flow”.
See ”The Compressor Does Not Work”.
The control system does not work
properly
Heat load higher than expected.
ROOM TEMPERATURE TOO LOW
(Low room temperature alarm)
See ”Compressor High Output Pressure”,
”Compressor Low Intake Pressure”.
See the control panel instruction manual;
check that the control panel and sensors
work properly.
Check: fresh air conditions and volume,
external air infiltration and latent load,
particularly with dehumidification.
The parameter settings on the control Check the room temperature setting; see the
panel are not correct.
control panel instruction manual
Electric heater does not work.
1) Check electric heater operation
2) Check electric heater power supply
3) If there is a heater alarm, remove the
cause and re-set the safety thermostat
The control system is not working.
See control panel instruction manual; check
that control panel and/or sensors work
properly.
Thermal leakage higher than expected Check thermal leakage and entry of external
air.
HUMIDITY CONTROL
PROBLEM
ROOM HUMIDITY TOO HIGH
(High room humidity alarm)
POSSIBLE CAUSE
A) The parameter settings on the
control panel are not correct.
B) Latent load higher than expected
C) The compressor does not function
during dehumidification.
E) The control system is not working.
ROOM HUMIDITY TOO LOW
(Low room humidity alarm)
CHECK / REMEDY
Check room humidity settings; see the
control panel instruction manual.
Check: latent load, fresh air conditions and
volume, external air infiltration
See “The Compressor Doesn’t Work”
See control panel instruction manual; check
that control panel and sensors work properly.
A) The parameter settings on the Check the room temperature setting; see
control panel are not correct.
also the control panel instruction manual.
B) Latent load lower than expected.
Check: quantity of the latent load, fresh air
conditions and volume, external air
infiltration
Monobloc downflow Units - XDF0221, XDF0281 - Rev 1.0. - Date: 01-07-1999 EN
33 (37)
INSTRUCTION MANUAL
XDF
FANS
PROBLEM
LACK OF AIRFLOW
POSSIBLE CAUSE
A) No power to the fans
B) The filters are dirty
C) The fans are rotating in the wrong
direction
D) The airflow is obstructed
E) Intervention of fan thermal
protection.
G) The pressure drop on the air
distribution system (ducts, suspended
ceiling, raised floor, etc.) is to high.
CHECK / REMEDY
Check power supply to the fan motors
Shake dust out of the cartridge and clean
with a vacuum cleaner. Change filter if
blocked. Check correct setting of the dirty
filter pressostat.
Swap two power supply phases and check
correct rotation direction. (See electrical
diagrams, RSF phase sequence relay).
Read the section on Air Distribution
Check the resistance of the fan windings.
Re-set then measure voltage and current.
1) Check the dimensions and characteristics
of the air distribution system
2) Increase the fan rotation speed (See Fan
Speed Regulation)
H) The control system signals an See the microprocessor control manual.
alarm even though the airflow is
correct; the microprocessor control
and/or the airflow sensor is not
working;
REFRIGERANT CIRCUIT
PROBLEM
POSSIBLE CAUSE
CHECK / REMEDY
HIGH COMPRESSOR OUTPUT
PRESSURE
A) Non-condensable air or gas in the
circuit, with bubbles in the flow sight
glass; supercooling of the liquid is
high.
B) Airflow is insufficient or air in the
remote condenser is too warm.
Evacuate the refrigerant circuit and recharge
1) Check fan operation and rotation direction
in the remote heat exchanger. (See
condenser/radiator instruction manual).
2) Remove any obstructions from the remote
condenser with compressed air or water.
3) Check pressure drop if air output is ducted
D) Too much refrigerant in the circuit; Remove some refrigerant from the circuit.
condenser
partially
flooded.
Refrigerant supercooling too high at
condenser output
E) High-pressure valves partially Check the opening of the valves.
closed
34 (37)
Monobloc downflow Units - XDF0221, XDF0281 - Rev 1.0. - Date: 01-07-1999 EN
INSTRUCTION MANUAL
XDF
REFRIGERANT CIRCUIT
PROBLEM
HIGH PRESSURE PRESSOSTAT
INTERVENES
LOW COMPRESSOR OUTPUT
PRESSURE
POSSIBLE CAUSE
CHECK / REMEDY
A) The condensation pressure control 1) Check condenser fan and fuses; re-set or
system is not functioning efficiently
replace the faulty fans;
2) Check setting and function of the RVC/e.
speed regulator (see Regulation of
condensation pressure)
B) High system output pressure
See High compressor output pressure
A) The condensation pressure control
system
is
not
working
(see
microprocessor control instruction
manual).
B) Intake pressure too low
1) Check the function and setting of the
condenser fan pressostat and speed
regulator
See Low Compressor Intake Pressure.
HIGH COMPRESSOR INTAKE
PRESSURE
Check: room thermal load especially during
dehumidification; the flow and conditions of
external air; external air leaks
B) System output pressure is too high See High Compressor Output Pressure
C) Too much refrigerant in the circuit
Remove some refrigerant from the circuit.
D) Liquid refrigerant return to Check
correct
thermostatic
valve
compressor intake
superheating (around 8-10°C); Check that
the valve sensor bulb is correctly positioned,
fixed and insulated
LOW COMPRESSOR INTAKE
PRESSURE
(possible freezing of the coil)
A) Room temperature too low
COMPRESSOR INTAKE LP
PRESSOSTAT INTERVENES
(low compressor intake pressure)
A) Thermal load higher than expected
See “Room temperature too low“
B) Low or zero airflow
See “Lack of airflow”
D) Refrigerant filter blocked
Check the refrigerant filter
E) Thermostatic valve incorrectly set Check
correct
thermostatic
valve
or defective
superheating (around 8-10°C); Check that
the valve sensor bulb is correctly positioned,
fixed and insulated.
F) Insufficient refrigerant charge
Check for leaks and re-charge the unit until
supercooling at the condenser output is 35°C.
A) Thermostatic valve incorrectly set Check that superheating of the thermostatic
or defective
valve is correct (around 8-10°C).
B) The filter dryer cartridge is dirty
Check whether the cartridge needs to be
changed; temperature difference before and
after the cartridge should be less than 2°C.
D) System output pressure is too low
See “Low compressor output pressure”.
Monobloc downflow Units - XDF0221, XDF0281 - Rev 1.0. - Date: 01-07-1999 EN
35 (37)
INSTRUCTION MANUAL
XDF
COMPRESSORS
PROBLEM
THE COMPRESSOR DOESN’T
WORK
COMPRESSOR INTERNAL
PROTECTION INTERVENES
THE COMPRESSOR IS NOISY
POSSIBLE CAUSE
A) Short
intervened
circuit
CHECK / REMEDY
protection
has Re-set the automatic switch and check the
cause of the short circuit. Before starting the
compressor check the resistance and
continuity of the compressor winding.
B) Intervention of compressor’s See Compressor Internal Protection has
internal protection
Intervened
C) The contactor is not working
Check the contacts and the contactor coil..
A) A phase is missing
Check the resistance of the compressor
winding. After re-setting, measure the
voltage and current of the three phases.
B) The motor is overloaded
Check that unit is operating within normal
limits
C) Power supply voltage too high or Check that the difference between the three
too low
power supply phases is less than 2%. With
monophase units, voltage must be within 10% and +6% of the nominal value.
D) The rotor is blocked
Replace the compressor
A) The compressor is damaged
B) Liquid return to the compressor
Call an authorised service centre to replace
the compressor.
Check expansion valve function and
superheating.
ELECTRIC RE-HEAT
PROBLEM
POSSIBLE CAUSE
CHECK / REMEDY
THE ELECTRIC HEATING ELEMENT The safety thermostat has intervened
Airflow is too low: See “Low or zero airflow”
IS NOT WORKING
Thermostat
connection
wire
is Check the continuity of the connection
interrupted
between the safety thermostat and the
control system
The contactor is not working
Check the contacts and the contactor coil.
Short circuit protection has intervened Re-set the lever of the automatic switch.
Check the cause of the short circuit
36 (37)
Monobloc downflow Units - XDF0221, XDF0281 - Rev 1.0. - Date: 01-07-1999 EN
INSTRUCTION MANUAL
XDF
FREE COOLING
PROBLEM
THE FREE-COOLING CYCLE IS NOT
ACTIVATED
POSSIBLE CAUSE
A) The damper motor is not working
B) The control system is incorrectly
calibrated
C) The control system is not working
CHECK / REMEDY
Repair or replace the damper motor.
Check the control system calibration.
See Microprocessor Control Manual; check
sensor function.
D) The circuit does not receive the free- Check connections to external control
cooling command (only in units
system (see Electrical Connections)
controlled by external CDC system).
ROOM TEMPERATURE TOO HIGH
The free-cooling damper has remained 1) The damper motor is not working; put the
damper in the re-circulation position
(high room temperature alarm)
open: the evaporator is exposed to
manually until the motor is repaired or
warm and / or humid external air
replaced
2) The minimum opening setting for the
damper is too wide: re-set the minimum
opening (see Microprocessor Control
Manual)
3) The base circuit is receiving an incorrect
command to open the damper (only in
units controlled by external CDC system
See ROOM TEMPERATURE TOO HIGH
A) The free-cooling damper has
ROOM TEMPERATURE TOO LOW
above
remained in the open position: the
(intervention of low ambient
evaporator is exposed to cold
temperature alarm threshold)
external air
1) The setting of the control system is not
B) Damper modulation is not working
correct. Check the setting of the control
correctly when external air is too
system.
cold.
2) The base circuit is receiving an incorrect
command to open the damper (only in units
controlled by external CDC system).
ROOM HUMIDITY TOO HIGH (in units The free-cooling damper has remained See Room temperature too high
with humidity control)
open: the evaporator is exposed to
warm and / or humid external air
(intervention of high room humidity
alarm)
HIGH COMPRESSOR INTAKE
The free-cooling damper has remained See Room temperature too high
PRESSURE
open: the evaporator is exposed to
warm and / or humid external air
The free-cooling damper has remained See Room temperature too high
LOW COMPRESSOR INTAKE
open: the evaporator is exposed to cold
PRESSURE
external air
(with possible freezing of the coil)
Monobloc downflow Units - XDF0221, XDF0281 - Rev 1.0. - Date: 01-07-1999 EN
37 (37)