Mitsubishi PUMY-P100YHM Technical & Service Manual page 40

Display
Abnormal point and detecting method
Overvoltage or voltage shortage
4220
Abnormal if any of followings are detected
during compressor operation;
• Decrease of DC bus voltage to 310V
• Instantaneous decrease of DC bus voltage to
350V.
• Increase of DC bus voltage to 760V.
• Decrease of input current of outdoor unit to
0.1A only if operation frequency is more than
or equal to 40Hz or compressor current is
more than or equal to 6A.
4230
Temperature of heatsink
If heatsink thermistor(TH8) detects
temperature indicated below 95
NOTE) TH8 is internal thermistor of power
module on power board.
4250
(1) Power module
Check abnormality by driving power module in
case overcurrent is detected.
(2) Compressor overcurrent interruption
Abnormal if overcurrent DC bus or
compressor is detected after compressor
starts operating for 30 seconds.
Over current level : 18.0A
4400
Outdoor fan motor
The outdoor fan motor is considered to be
abnormal if the rotational frequency of fan
motor is abnormal when detected during
operation.
Fan motor rotational frequency is abnormal if;
• 100 rpm or below detected continuously
for 15 seconds at 20: or more outside
air temperature
• 50 rpm or below or 1500 rpm or more
detected continuously for 1 minute.
Causes
Decrease of power supply voltage
Disconnection of compressor wiring
Defective 52C
Defective outdoor converter circuit board
Disconnection or loose connection of
CN5 on the outdoor power circuit board
Defective 52C drive circuit of outdoor
power circuit board
Disconnection or loose connection of
CN2 on the outdoor power circuit board.
The outdoor fan motor is locked.
Failure of outdoor fan motor
Airflow path is clogged.
Rise of ambient temperature
Defective thermistor
Defective input circuit of outdoor power
circuit board
Failure of outdoor fan drive circuit
Outdoor stop valve is closed.
Decrease of power supply voltage
Looseness, disconnection or converse
of compressor wiring connection
Defective compressor
Defective outdoor power circuit board
Stop valve of outdoor unit is closed.
Decrease of power supply voltage
Looseness, disconnection or converse
of compressor wiring connection
Defective fan of indoor/outdoor units
Short cycle of indoor/outdoor units
Defective input circuit of outdoor
controller board
Defective compressor
Failure in the operation of the DC fan motor
Failure in the outdoor circuit controller board
40
Check points
Check the facility of power supply.
Correct the wiring (U·V·W phase) to
compressor. (Outdoor power circuit
board)
Replace 52C.
Replace outdoor converter circuit board.
Check CN5 wiring on the outdoor power
circuit board.
Replace outdoor power circuit board.
Check CN2 wiring on the outdoor power
circuit board.
Check outdoor fan.
Check air flow path for cooling.
Check if there is something which
causes temperature rise around outdoor
unit.
(Upper limit of ambient temperature is 46 .)
Turn off power, and on again to check if
4230 is displayed within 30 minutes.
Check thermistor <TH8> temperature
by micro computer.
Replace outdoor power circuit board.
Replace outdoor controller circuit board.
Open stop valve.
Check facility of power supply.
Correct the wiring (U·V·W phase) to
compressor.
(Outdoor power circuit board).
Check compressor.
Replace outdoor power circuit board.
Open stop valve.
Check facility of power supply.
Correct the wiring (U·V·W phase) to
compressor.
(Outdoor power circuit board).
Check indoor/outdoor fan.
Solve short cycle.
Replace outdoor controller circuit board.
Check compressor.
Before the replacement of the outdoor
controller circuit board, disconnect the
wiring to compressor from the outdoor
power circuit board and check the
output voltage among phases, U, V, W,
during test run (SW7-1 ON). No defect
on board if voltage among phases (U-V,
V-W and W-U) is same. Make sure to
perform the voltage check with same
performing frequency.
Check or replace the DC fan motor.
Check the voltage of the outdoor circuit
controller board during operation.
Replace the outdoor circuit controller
board. (when the failure is still indicated
even after performing the remedy 1
above.)