Mitsubishi Electric CITY MULTI PUMY-P112VKM6 Service Manual page 51

4220 (U9): Voltage shortage/Overvoltage/PAM error/L1 open phase/
Abnormal points and detection methods
Any of the following symptoms are detected;
• Decrease of DC bus voltage to 200 V (1-phase), 350 V
(3-phase)
• Increase of DC bus voltage to 400 V (1-phase), 760 V
(3-phase)
• DC bus voltage stays at 310 V or less for 30 consecu-
tive seconds when the operational frequency is over 20
Hz.
Any of the following conditions is satisfied while the detec-
tions value of primary current is 0.1 A or less.
• The operational frequency is 40 Hz or more.
• The compressor current is 6 A or more.
Diagnosis of failure
Is there any abnormality on wiring?
7, 8
Which sub code is displayed?
Does the DC bus voltage rise to
approx. 380 V at PAM driving?
Is there any abnormality on PAM
wirings or reactor?
Is there any abnormality at the
PAM circuit on the outdoor power
circuit board?*
Is there any abnormality at the PAM
power supply circuit or 52C relay drive
signal circuit on the outdoor multi
controller?*
Continue to the next page.
*Refer to "How to check the parts".
OCH790 _51
Primary current sensor error/Power synchronization sig-
nal error
Yes
No
6
3
No
No
No
No
Causes and checkpoints
• Decrease/increase of power supply voltage
• L1 open-phase (3-phase only)
• Primary current sensor failure
• Disconnection of compressor wiring
• Malfunction of 52C relay
• Defective outdoor power circuit board
• Malfunction of 52C relay driving circuit on outdoor multi
controller circuit board
• Disconnection of CN5 (3-phase only)
• Disconnection of CN2
• Malfunction of primary current detecting circuit on out-
door power circuit board
• Malfunction of resistor connected to 52C relay on out-
door power circuit board (3-phase only)
a. L1 open-phase (3-phase model only)
b. Disconnection of compressor wiring
c. Disconnection of terminal block for power supply
d. Disconnection of noise filter circuit board
e. Disconnection of power circuit board
f. Disconnection of CN52C (1-phase model only)
g. Disconnection of CN5 (3-phase model only)
h. Disconnection of CN2
The sub codes are displayed by an operation of
The sub codes are displayed by an operation of The sub codes are displayed by an operation of
SW1 on the outdoor controller board. SW1 on the outdoor controller board. SW1 on the outdoor multi controller circuit board.
3: PAM error
SW1 Setting Display on LED1, 2
1 2 3 4 5 6 7 8
6: Input sensor trouble
ON
7: Shortage voltage trouble
OFF
1 2 3 4 5 6 7 8
8: Overvoltage trouble
Yes
Check the power supply facility.
Yes
Correct the wiring.
Replace the reactor if it is broken.
Yes
Replace the outdoor power circuit board
(defective outdoor power board).
Yes
Replace the outdoor multi controller circuit board
(breakage of wiring for PAM controlling power
supply).
Replace the outdoor power circuit board
(defective outdoor power circuit board).
1-phase: 1-phase model
3-phase: 3-phase 4-wire model
The black square (■) indicates a switch position.
Chart 1 of 2