Mitsubishi Electric PUMY-P36NKMU2-BS Technical & Service Manual page 69

Check code
4220
Primary current sensor error/Power synchronization signal error
(U9)
Abnormal points and detection methods
If any of following symptoms are detected;
●Decrease of DC bus voltage to 200 V
●Increase of DC bus voltage to 400 V
●DC bus voltage stays at 310 V or less for consecutive 30 seconds when
the operational frequency is over 20 Hz.
● When any of the following conditions has been satisfied while the
detection value of primary current is 0.1 A or less.
1. The operational frequency is 40 Hz or more.
2. The compressor current is 6 A or more.
●Diagnosis of defects
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 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.
OCH695B
Voltage shortage/Overvoltage/PAM error/L1 open-phase/
Diagnosis
No
6
3
No
No
No
No
Causes and checkpoints
Decrease/increase of power supply voltage.
Primary current sensor failure
2
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
0 Malfunction of primary current detecting circuit on
outdoor power circuit board
The black square (■) indicates a switch position.
a. Disconnection of compressor wiring
Yes
b. Disconnection of CN52C
c. Disconnection of CN5
d. Disconnection of CN2
The sub codes are displayed by an
The sub codes are displayed
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: Primary current 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.
Replace the outdoor power circuit board
(Defective outdoor power circuit board).
69
Chart 1 of 2
Remedy
Correct the wiring.