175
17.5.31 Compressor Overheating (F20)
Malfunction Decision Conditions:
During operation of cooling and heating, when temperature above 117°C is detected by the outdoor discharge
pipe temperature sensor.
Malfunction Caused:
1 Faulty outdoor discharge pipe temperature sensor.
2 2/3 way valve closed.
3 Refrigerant shortage (refrigerant leakage).
4 Clogged expansion valve or strainer.
5 Faulty outdoor unit PCB (main).
6 Faulty compressor.
Abnormality Judgment:
Continue 4 times in 20 minutes.
Troubleshooting:
For safety reason and to prevent component breakdown,
always switch off the power before remove and connect the component.
Check the outdoor discharge pipe
temperature sensor.
Does it conform to the
sensor characteristic chart?
Check the 2/3 way valve.
Check for clogged expansion
valve or strainer.
Is the expansion valve or
strainer clogged (ice formed)?
Is abnormality happened
again?
Reclaim and recharge for a
specified amount of fresh refrigerant.
Is the 2/3 way valve closed?
Check for gas leakage.
Is the oil oozing out from
the 2/3 way valve?
Replace the outdoor discharge
pipe temperature sensor.
Open the 2/3 way valve.
No
No
No
No
No
Yes
Yes
Yes
Yes
Yes
- Repair the pipe flare or
union nuts.
- Reclaim and recharge
refrigerant.
- Repair expansion valve
and/or strainer.
- Reclaim and recharge
refrigerant.
- Replace the outdoor unit
PCB (main).
- Replace the compressor.
Procedure complete.
Caution
