Fault
Possible cause
Remedy
Fan of the internal device
continues to run, even
though the equipment is
switched OFF;
No speed change possi-
ble
Controller (internal de-
vice) faulty
Replace controller
In cooling mode, limited
air delivery and internal
device whistles
Ice forms at the heat ex-
changer of the internal
device
Fix leak; fill system with
refrigerant
No air delivery at the ex-
ternal unit
No voltage at the exter-
nal fan connection
Check the power supply
and wiring between the
internal device and the
external unit
Replace PCB (external
unit)
External fan capacitor
faulty
Replace capacitor
External fan motor faulty Replace motor
In heating mode, the heat
exchanger of the external
unit is icing up
Temperature sensor of
the heat exchanger of
the external unit faulty or
incorrect connection
Check connection and re-
place temperature sen-
sor, if required
Controller (external unit)
faulty
Replace controller
Ice forms at the bottom of
the external unit
Condensate drain frozen
up
Connect defrost heater
Compressor (in the exter-
nal unit) does not run
No voltage at the term-
inals of the external unit
Check the electrical con-
nection between the in-
ternal device and the
external unit
Replace PCB (internal
device)
Voltage too low at the
terminals of the external
unit
Check power supply
Compressor capacitor
faulty
Replace capacitor
Compressor motor faulty Replace motor
Compressor shutdown
due to overload (low vol-
tage or high tempera-
ture)
Check voltage;
switch OFF system for
one hour
Diagnosis
(cont.)
26
Troubleshooting
5692
689
GB