4
Excessive discharge pressure.
5
The winding on the electrical motor is interrupted or in short
circuit.
Intervention of the thermal protector
D
1
Low voltage supply to the compressor (unbalanced phases on
the tri-phase motors).
2
Defective thermal protector.
3
Defective electric-run condenser.
4
Excessive discharge pressure.
5
High suction pressure.
6
Overheated compressor, hot return gas.
7
Winding of the compressor motor in short circuit.
The compressor starts up and circulates, the functioning cycles are of
E
brief duration
1
Thermal protector.
2
Thermostat.
3
Intervention of the high pressure switch, due to the insufficient
cooling of the condenser.
4
Intervention of the high pressure switch, due to the excessive
load of refrigerant gas.
5
Intervention of the low pressure switch, due to the scarce load of
refrigerant gas.
6
Intervention of the low pressure switch, due to the restriction or
clogging of the expansion valve.
The compressor operates uninterruptedly or for long periods
F
1
Scarce load of refrigerant gas.
2
Thermostat with contacts locked in closure.
3
System not sufficiently sized in function of the load.
4
Excessive load to cool or insufficient insulation.
5
Evaporator covered with ice.
6
Restriction in the system circuit.
7
Clogged condenser.
Electric-run condenser damaged, interrupted, or in short circuit
G
1
Wrong electric-run condenser.
Start-up relay defective or burnt out
H
1
Wrong relay.
2
Relay mounted in the incorrect position.
3
Wrong lectric-run condenser.
Cold-room temperature too high
I
1
Thermostat regulated too high.
2
Undersized expansion valve.
3
Undersized evaporator.
4
Insufficient air circulation.
Frosted suction piping
L
1
Expansion valve with excessive passage of gas or oversized.
2
Expansion valve locked in open position.
3
Evaporator fan does not work.
4
Gas load too high.
POSSIBLE CAUSES
SOLUTIONS
4
Identify the cause and substitute the relay if
necessary.
5
Replace the compressor.
1
Identify the cause and eliminate it.
2
Check its characteristics and replace it if
necessary.
3
Identify the cause and eliminate it.
4
Check the ventilation and any potential
restrictions or obstructions in the system
circuit.
5
Check the sizing of the system. Replace the
condensing unit with a more powerful one, if
necessary.
6
Check the refrigerant load; if need be, repair
the loss and add gas if necessary till the
charge stated in the label.
7
Replace the compressor.
1
See previous point (thermal protector
intervention).
2
Small differential; correct the regulation.
3
Check the correct functioning of the motor
fan or clean the condenser.
4
Reduce the load of refrigerant gas.
5
Repair the loss and add refrigerant gas. till
the charge stated in the label.
6
Replace the expansion valve.
1
Repair the loss and add refrigerant gas till the
charge stated in the label.
2
Replace the thermostat.
3
Replace the system with a more powerful
one.
4
Reduce the load and improve insulation, if
possible.
5
Perform defrosting till the charge stated in the
label .
6
Identify the resistance and eliminate it.
7
Clean the condenser.
1
Replace the condenser with the correct type.
1
Replace the relay with the correct one.
2
Re-assemble the relay in the correct position.
3
Replace the condenser with the correct type.
1
Regulate it correctly.
2
Replace the expansion valve with a suitable
one.
3
Replace it, increasing the surface of the
evaporator.
4
Improve air circulation,
1
Adjust the valve or substitute it with a correctly
sized one.
2
Clean the valve of foreign substances and
replace it, if necessary.
3
Identify the cause and eliminate it.
4
Reduce the load.
WSH-WTH Pag. 55
UK
REV. 01 04/14