Mitsubishi Electric PUMY-P112VKM1 Service Manual page 75

Check code
4220
Abnormal points and detection methods
Abnormal if any of following symptoms are detected;
1 P112/125/140V model
●Decrease of DC bus voltage to 200 V
●Increase of DC bus voltage to 400 V
●DC bus voltage stays at 310V or lower for censecutive 10 seconds
2 P112/125/140Y model
●Decrease of DC bus voltage to 350 V
●Increase of DC bus voltage to 760 V
●Decrease of primary current to 0.1 A
Note:
The detection is active only when the operational frequency is 40 Hz or
more, or the compressor current is 6 A 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. 350 V at PAM driving?
Is there any abnormality on
PAM wirings?
Is there any abnormality at the
PAM circuit on the outdoor power
circuit board?
Is there any abnormality at
the PAM power supply circuit on the
outdoor multi controller circuit board?
Continue to the next page
OCH576
Undervoltage/Overvoltage/PAM error/L1 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 circuit board
Malfunction of 52C driving circuit on outdoor multi
controller circuit board
Disconnection of CN5
Disconnection of CN2
Malfunction of primary current detecting circuit on
outdoor power circuit 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 displayed The sub codes are displayed by an
operation of SW1 on the outdoor by an operation of SW1 on
multi controller circuit board. the outdoor multi controller
circuit board.
SW1 Setting
Display on LED1,2
3: PAM error 3: PAM error
1 2 3 4 5 6 7 8
6: Input sensor trouble 6: Input sensor trouble
ON
7: Shortage voltage trouble 7: Undervoltage trouble
OFF
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 circuit board
Yes
(Defective outdoor power circuit board).
Replace the outdoor multi controller circuit
board. Breakage of wiring for PAM controlling
Yes
power supply, and such.
75
Chart 1 of 2
Remedy
Correct the wiring.
PAM error