Mitsubishi Electric PUHY-P72THMU-A Service Handbook page 187

[ IX Troubleshooting ]
1. Error Code
4240 (YHMU-A)
Overload protection
2. Error definition and error detection method
If the output current of "(Iac) >Imax (Arms)" or "THHS > 95°C [203°F] " is continuously detected for 10 minutes or more during
inverter operation.
Model Imax(Arms)
P72, P96 models
P120 model
3. Cause, check method and remedy
Cause
(1) Air passage blockage
(2) Power supply environment
(3) Inverter failure
(4) Compressor failure
Refer to section -6- "Inverter (YHMU-A)" under part [4] Troubleshooting Principal Parts for error codes related to the
inverter.(page 252)
HWE08040
19
27
Check that the heat sink cooling air passage is not blocked
Power supply voltage is 414 V or above.
Refer to IX [4] -6-.(page 252)
Check that the compressor has not overheated during operation.
-> Check the refrigerant circuit (oil return section).
Refer to IX [4] -6- (2) [2].(page 254)
- 178 -
Check method and remedy
GB