Mitsubishi Electric PUMY-P112VKM3 Technical & Service Manual page 71

Check code
Voltage shortage/overvoltage/PAM error/L1open phase/primary
4220
(U9)
Abnormal points and detection methods
Abnormal if any of following symptoms are detected;
●Decrease of DC bus voltage to 200 V (V model), 350 V (Y model)
●Increase of DC bus voltage to 400 V (V model), 760 V (Y model)
●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 is 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 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
OCH632A
current sensor error/power synchronization signal error
Diagnosis
No
6
3
No
No
No
No
Causes and check points
Decrease/increase of power supply voltage
LI open-phase (Y model only)
2
Primary current sensor failure
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
0 Disconnection of CN2
1 Malfunction of primary current detecting circuit on
outdoor power circuit board
The black square (■) indicates a switch position.
a. LI open-phase (Y model only)
b. Disconnection of compressor wiring
Yes
c. Disconnection of CN52C (V model only)
d. Disconnection of CN5
e. Disconnection of CN2
The sub codes are displayed
The sub codes are displayed by an
by an operation of SW1 on
operation of SW1 on the outdoor multi
the outdoor multi controller
controller circuit board.
circuit board.
3: PAM error
SW1 Setting
Display on LED1,2 3: PAM error (V model only)
6: Input sensor trouble
1 2 3 4 5 6 7 8
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).
71
Chart 1 of 2
Remedy
Correct the wiring.