8 Troubleshooting
247
SMGB0087 rev.0 - 12/2013
8
Alarm code
20
Abnormality of thermistor for discharge gas temperature (compressor thermistor)
• The RUN LED ickers and “ALARM” is displayed on the remote control switch.
• The unit number, the alarm code and the unit code are alternately displayed on the set temperature section. The unit
number and the alarm code are displayed on the display of the outdoor unit PCB.
- This alarm code is indicated when the thermistor is short-circuited (less than 1 kΩ) or cut (greater than 6 MΩ) during
the cooling or heating operation.
Is the thermistor connected to
THM9 of PCB?
Connect it
No
Yes
Is the resistance of THM9
between 1kΩ and 6kΩ?
Faulty thermistor
No
Yes
Faulty PCB
Thermistor on top of
compressor
Phenomenon Cause Check item
Action
(Turn OFF Main Switch)
Faulty top of compressor ther-
mistor
Fault Check resistance Replace thermistor if faulty
Incorrect connection Check wiring to PCB1 Repair wiring and connections
Faulty PCB1
Replace PCB1 and check op-
eration
Replace PCB1 if faulty
Ambient temperature (ºC)
Thermistor characteristics
Thermistor resistance (kΩ)
The resistance value have fudge factor (+10%).
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