HWMC
38
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RG66008809 - Rev 00
11 TROUBLESHOOTING
SYMPTOM Cooling
Heating
Who can take
corrective action
U = User
S = specialised
personnel
Possible control panel
indication
Probable cause
Possible remedy
G Lack of gas
X
X
S
LOW Pressure Alarm
triggered by sensor -
circuit 1
Cooling circuit leak
Check the cooling circuit using a leak detector
after pressurising the circuit to approximately
4 bars. Repair, evacuate and refill.
I Frost in liquid
pipe downstream
from a filter
X X
S
HIGH Pressure Alarm
triggered by sensor -
circuit 1
LOW Pressure Alarm
triggered by sensor -
circuit 1
Liquid filter clogged
Replace the filter
L The unit works
continuously
without ever
stopping
X
X
S
Lack of refrigerant gas
See item G
X X
U
Wrong setting of operating
thermostat
Check the setting
X
X
S
Thermal overload
Reduce the thermal load
X X
S
Compressor does not provide the
rated heating capacity
Check and replace or overhaul
X
X
Liquid filter clogged
Replace
M The unit works
regularly but with
an insufficient
capacity
X
X
S
Low level of refrigerant
See item G
X X
S
4-way cycle reversing valve
defective
Check the valve power supply and coils and
replace the valve if necessary
N Frost in the
compressor intake
pipe
X X
S
Expansion valve is not working
properly
Check replace
X
S
Water circulation pump blocked
Release the pump
X
X
S
Water circulation pump defective
Check the pump and replace it if necessary
X
X
S
Low level of refrigerant
See item G
X
X
S
Liquid filter clogged
Replace
O The defrosting
cycle is never
activated
X S
4-way cycle reversing valve
defective
Check the valve power supply and coils and
replace the valve if necessary
X S
The defrost thermostat has broken
down or has been set incorrectly
Check and replace if defective or change the
setting
P Abnormal
noises detected in
the system
X
X
S
The compressor is noisy
Check and replace if necessary
X
X
S
The panels vibrate
Fasten properly
