Voltage Shortage; Overvoltage; Pam Error - Mitsubishi Electric PUMY-P250YBM Technical & Service Manual

Check code
4220
(U9)
Abnormal points and detection methods
If any of following symptoms are detected;
● Decrease of DC bus voltage to 200 V (Single-phase), 350 V (3-phase)
● Increase of DC bus voltage to 400 V (Single-phase), 760 V (3-phase)
● DC bus voltage stays at 310 V or less for consecutive 30 seconds when
the operational frequency is over 20 Hz.
● When any of following conditions is satisfied while the detections 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 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?*
*Refer to "8-5. HOW TO CHECK THE PARTS".
Continue to the next page.
OCH760
Voltage shortage /Overvoltage/PAM error/L1 open phase/
Primary current sensor error/Power synchronization signal error
Diagnosis
No
3
No
vzv
No
No
No
Causes and checkpoints
Decrease/increase of power supply voltage
L1 open-phase (3-phase only)
2
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
outdoor power circuit board
Malfunction of resistor connected to 52C relay on
outdoor power circuit board (3-phase only)
The black square (■) indicates a switch position.
a. L 1 open-phase (3-phase only)
b. Disconnection of compressor wiring
Yes
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 (Single-phase only)
g. Disconnection of CN5 (3-phase only)
The sub codes are The sub codes are
h. Disconnection of CN2
displayed by an operation displayed by an operation
of SW1 on the outdoor of SW1 on the outdoor
6
controller board. controller board.
SW1 Setting
Display on LED1,2
1 2 3 4 5 6 7 8
ON
OFF
1 2 3 4 5 6 7 8
Yes
Correct the wiring.
Yes
Replace the reactor if it is broken.
Replace the outdoor power circuit board
Yes
(defective outdoor power board).
Replace the outdoor multi controller
circuit board (breakage of wiring for PAM
Yes
controlling power supply).
Replace the outdoor power circuit board
(defective outdoor power circuit board).
60
Single phase: single phase model
3-phase: three phase for wire model
Remedy

3: PAM error

3: PAM error
6: Input sensor trouble 6: Input sensor trouble
7: Shortage voltage trouble 7: Shortage voltage trouble
8: Overvoltage trouble 8: Overvoltage trouble
Check the power supply facility.
Chart 1 of 2