Mitsubishi Electric PLFY Series Technical & Service Manual page 25

Pressure sensor (inner water) PS1
Pressure sensor (outlet water) PS2
1) Check that the pressure sensor is connected.
2) Check the pressure sensor wiring for breakage.
9-1-3. Drain pump
Drain pump
1 Red
2 Purple
3 Black
1. Check if the drain float switch works properly.
2. Check if the drain pump works and drains water properly in cooling operation.
3. If no water drains, confirm that the check code 2502 will not be displayed 10 minutes after the operation starts.
Note: The drain pump for this model is driven by the internal DC motor, so it is not possible to
measure the resistance between the terminals.
Normal
Red–Black: Input 13 VDC
Purple–Black: Abnormal (check code 2502) if it outputs 0–13 V square wave (5 pulses/rotation), and
the number of rotation is not normal.
9-1-4. DC Fan motor (fan motor/indoor controller board)
Check method of indoor fan motor (fan motor/indoor controller board)
Notes
· High voltage is applied to the connector (CNMF) for the fan motor. Pay attention to the service.
· Do not pull out the connector (CNMF) for the motor with the power supply on.
(It causes trouble of the indoor controller board and fan motor.)
Self check
Conditions : The indoor fan cannot rotate.
Indoor controller board fuse check
Is the fuse normal?
Yes
Wiring contact check
Contact of fan motor connector (CNMF)
Is there contact failure?
No
Power supply check (Remove the connector (CNMF))
Measure the voltage in the indoor controller circuit
TEST POINT : V (between 1 (+) and 4 (-) of the fan connector): V
DC
TEST POINT
: V (between 5 (+) and 4 (-) of the fan connector): V
CC
Is the voltage normal?
No
Replace indoor
controller board.
Check the operation.
Fail
Replace the defective fan motor.
TCH124A
The fan starts to rotate.
Is the resistance
between the terminals of
drain pump normal?
Replace the drain pump.
Yes
Correct the wiring.
board.
Yes
Replace the defective fan motor.
Check the operation of fan.
Replace indoor controller board.
OK
Complete.
25
No
294-325 VDC
DC
15 VDC
CC
OK
Complete.
Fail
Replace the defective fan motor.
Replace the indoor controller board.