Mitsubishi Electric PQHY-P72TYHMU-A Service Handbook page 261

[ IX Troubleshooting ]
1. Error Code
4220 (YHMU-A)
Logic error (Detail code 111)
2. Error definition and error detection method
H/W error
If only the H/W error logic circuit operates, and no identifiable error is detected.
3. Cause, Check method and remedy
In the case of 4220
(1) External noise
(2) INV board failure
Refer to section -6- "Inverter (YHMU-A)" under part [4] Troubleshooting Principal Parts for error codes related to the
inverter.(page 333)
1. Error Code
4220
Low bus voltage at startup (Detail code 131)
2. Error definition and error detection method
When Vdc 160 V is detected just before the inverter operation.
3. Cause, check method and remedy
(1) Inverter main circuit failure
Same as detail code 108 of 4220 error
Refer to section -6- "Inverter" under part [4] Troubleshooting Principal Parts for error codes related to the inverter.
HWE09080
Cause
- 252 -
Check method and remedy
Refer to IX [4] -6- (2) [1].(page 335)
GB