Error Code [4121]; Error Code [4124] - Mitsubishi Electric HP120TNU-A Service Handbook

[7-6 Error Code Definitions and Solutions: Codes [4000 - 4999] ]
7-6-4 Error Code [4114]
1. Error code definition
Indoor unit fan motor error
2. Error definition and error detection method
When the fan motor output from the indoor unit circuit board is ON and when the rotation speed input from the fan motor cannot
be detected for 30 seconds or more
3. Cause, check method and remedy
Cause
(1) Fan motor connector contact failure
(2) Indoor unit circuit board failure
(3) Fan motor fault
7-6-5 Error Code [4116]
1. Error code definition
RPM error/Motor error
2. Error definition and error detection method
LOSSNAY
The motor keep running even if the power is OFF.
The thermal overload relay is ON. (Only for the three-phase model)
Indoor unit
If detected less than 180rpm or more than 2000rpm, the indoor unit will restart and keep running for 3 minutes.If detected
again, the display will appear.
3. Cause, check method and remedy
(1) Board failure
(2) Motor malfunction
(3) Solenoid switch malfunction
7-6-6

Error Code [4121]

1. Error code definition
Function setting error
2. Error source, cause, check method and remedy
Error source
Outdoor unit (1) Dip switch setting error on the control board
(2) Connector connection error on the control
board
(3) Control board failure
HWE18220_GB
Check the fan motor connector CNMF for proper connection.
Remove the fan motor connector CNMF and check the voltage at the
indoor unit circuit board.
Testing point
Replace the indoor unit circuit board if the voltage is abnormal.
If the 4114 error persists after the indoor unit circuit board is replaced,
replace the fan motor as well.
Replace the fan motor if the voltage is normal in step (2) above.
If the 4114 error persists after the fan motor is replaced, replace the in-
door unit circuit board as well.
Cause
Cause
Check method and remedy
1. 280 VDC (Between CNMF1 (+) and CNMF4 (-))
2. 15 VDC (Between CNMF5 (+) and CNMF4 (-))
Check method and remedy
Replace the board.
Check for the motor and the solenoid switch.
Check method and remedy
Check the SW6-1 setting on the control board
Check that nothing is connected to the connector
CNAF on the control board.
Replace the control board if no problems are
found with the two items above.
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