Voltage Shortage/Overvoltage; Pam Error; T Open-Phase; Power Synchronization Signal Error - Mitsubishi PUMY-P60NKMU Technical & Service Manual

Check code
4220
Abnormal points and detection methods
Abnormal if any of following symptoms are detected;
●Decrease of DC bus voltage to 200V
●Increase of DC bus voltage to 400V
●Decrease of primary current
(The detection is active only when the operational frequency is 40Hz or
more, or the compressor current is 5A or more.)
●Diagnosis of defectives
Make sure to turn the power OFF before connecting/disconnecting
any connectors, or replacing boards.
Is there any abnormality on wirings?
7,8
Which sub code is displayed?
Does a DC bus voltage raise to
approx. 350V at PAM driving?
Is there any abnormality on
PAM wirings?
Is there any abnormality at the
PAM circuit on the outdoor power
board?
Is there any abnormality at
the PAM power supply circuit on the
controller board?
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OCH502C
Voltage shortage/Overvoltage/PAM error/T open-phase/

Power synchronization signal error

Diagnosis
No
6
1
No
No
No
No
Causes and check points
Decrease/increase of power supply voltage, or T
open-phase
Disconnection of compressor wiring
Malfunction of 52C
Disconnection or contact failure of CN52C
Defective outdoor power board
Malfunction of 52C driving circuit on outdoor
controller board
Disconnection of CN5
Disconnection of CN2
Malfunction of primary current detecting circuit on
outdoor power board
The black square (■) indicates a switch position.
a. T open-phase
b. Disconnection of compressor wiring
Yes
c. Disconnection of CN52C
d. Disconnection of CN5
e. Disconnection of CN2
The sub codes are The sub codes are The sub codes are
displayed by an operation displayed by an operation displayed by an operation
of SW1 on the outdoor of SW1 on the outdoor of SW1 on the outdoor
controller board. controller board. controller board.
SW1 Setting
Display on LED1,2

3: PAM error

3: PAM error 3: PAM error
1 2 3 4 5 6 7 8
6: Input sensor trouble 6: Input sensor trouble 6: Input sensor trouble
ON
7: Shortage voltage trouble 7: Shortage voltage trouble 7: Shortage voltage trouble
OFF
8: Overvoltage trouble 8: Overvoltage trouble 8: Overvoltage trouble
1 2 3 4 5 6 7 8
Check the power supply facility.
Yes
Yes
Replace the outdoor power board
Yes
(Defective outdoor power board).
Replace the outdoor controller board.
Breakage of wiring for PAM controlling
Yes
power supply, and such.
53
Chart 1 of 2
Remedy
Correct the wiring.
PAM error.