36
7425MUM661
Model: CWB FC
- Use and Maintenance Manual
Rev02
Cause
Alarm signal or
symptom
Solution
Execution
2. (continue) The compressor doesn’t start
Circuit breaker protection of the
compressors open (QC1, QC2)
AC1
Circuit 1 compressors thermal
protection
Look for short circuits in the
motor windings of the
compressor.
Check for possible over-
absorption of current due to
too low voltage; combined
with operating conditions near
the limits: check the power
supply voltage and operating
conditions
Specialised
personnel
Intervention of the phase-sequence
relay
A02
Reverse phase protection
Reverse the two phases
upstream from the cut-off
switch of the unit's electrical
panel (see paragraph 4.2)
Specialised
personnel
Contactor of the compressor open
The compressor icon is
on but the compressor
is stopped
Check the voltage at the coil
of the contactor of the
compressor and the continuity
of the coil itself
Specialised
personnel
3. Intervention of the high-pressure pressure switch
Condenser obstructed or insufficient
air flow-capacity
AH1
Circuit 1 high pressure alarm
Remove dirt from the
condenser and any obstacles
to the flow of air. Wait for the
refrigerant pressure to drop
below the reset value (33 bar
g), then rearm the high-
pressure switch by pressing
the button on top of it (see
figure in paragraph 7.2)
User
The unit has operated outside its
operating limits (such as air or water
too hot)
AH1
Circuit 1 high pressure alarm
If possible, restore conditions
that are compatible with the
operating limits.
Rearm the pressure switch
(paragraph 7.2).
User
Fan not working
AH1
Circuit 1 high pressure alarm
See point 6
Excessive refrigerant charge
High subcooling
(greater than
18°F//10K)
Drain excess refrigerant
Specialised
personnel
Presence of incondensable gas or air
in the refrigerant circuit
Presence of bubbles on
the refrigerant sight
glass, also with
subcooling values
greater than 9°F//5 K
Drain the refrigerant circuit,
create vacuum and recharge
Specialised
personnel
Refrigerant filter clogged or
thermostatic valve stuck
Pipe downstream from
the component covered
with frost.
Check and replace.
Specialised
personnel
Water pump blocked or defective
(only for heat pump operation)
AH1
Circuit 1 high pressure alarm
Unlock or replace the pump
Specialised
personnel