Mitsubishi Electric PUHY-HP72 Service Handbook page 157

[7-6 Error Code Definitions and Solutions: Codes [4000 - 4999] ]
7-6-25 Error Code [4250] Detail Codes 121, 128, and 122
1. Error code definition
DCL overcurrent error (H/W) (Detail code 121 and 128)(outdoor unit) DCL overcurrent error (S/W) (Detail code 122)
(outdoor unit)
2. Error definition and error detection method
When a DCL overcurrent is detected by the electric current sensor
3. Cause, check method and remedy
Cause
(1) Inverter-output-related
items
For inverter-related error codes, refer to the following page(s). [8-9 Troubleshooting Inverter Problems]
7-6-26 Error Codes [4255, 4256] Detail Code 137
1. Error code definition
Motor synchronization loss (Detail code 137)
2. Error definition and error detection method
Fan motor locking was detected during operation.
3. Cause, check method and remedy
Cause
(1) Fan motor locking
(2) Fan motor failure
(3) Fan board failure
For inverter-related error codes, refer to the following page(s). [8-9 Troubleshooting Inverter Problems]
36
- chapter 7
Check method and remedy
Refer to the following page(s). [8-9-2 Checking the Inverter Board Error Detection
Circuit]
Refer to the following page(s). [8-9-3 Checking the Compressor for Ground Fault
and Coil Resistance Problems]
Refer to the following page(s). [8-9-4 Checking the Inverter for Damage at No-Load]
Refer to the following page(s). [8-9-5 Checking the Inverter for Damage during Com-
pressor Operation]
Refer to the following page(s). [8-9-11 Checking the Installation Conditions]
Check the fan blades for objects obstructing fan rotation.
Refer to the following page(s).
[8-9-7 Checking the Fan Motor for Ground Fault and Coil Re-
sistance Problems]
Refer to the following page(s).
[8-9-8 Checking the Fan Board Error Detection Circuit at No
Load]
[8-9-9 Checking the Fan Board for Damage at No Load]
[8-9-10 Checking the Fan Board for Damage with Load]
Check method and remedy
HWE18240_GB