Other Troubles And Causes - Mitsubishi Electric Mr.Slim PKH18FL Technical & Service Manual

2. OTHER TROUBLES AND CAUSES

Auto vanes do not work.
Unit stops after 5 to
20 seconds operation
Power ON/OFF button
is not available.
Check
Diagnosis of malfunction
code
Abnormality of room temper-
1
ature thermistor (RT1)
Abnormality of indoor coil
2
thermistor (RT2)
Abnormality of drain sensor
4
Malfunction of drain pump
5
Coil frost protection is work-
6
ing.
Abnormality in outdoor unit
8
The number of check code shows times of Buzzer sound.
Auto vane motor does not work.
Connector is poorly connected.
Auto vane motor is poorly assembled.
Indoor controller board is damaged.
Protection function is working.
Indoor/outdoor connecting wire is connected
incorrectly.
Indoor/outdoor connecting wire shorts.
Compressor protector is damaged.
Defroster is broken.
Remote controller is damaged.
Transmission wire is poorly connected
Cause
1) Bad contact of thermistor
2) Damaged thermistor
1) Bad contact of transmission
wire
2) Damaged thermistor
1) Malfunction of drain pump
2) Damaged drain sensor
1) Short cycle of air cycle
2) Dirty air filter
3) Damaged fan
4) Abnormal refrigerant
1) Wrong wiring of indoor/outdoor
connecting wire
2) Reversed phase
3) Protection device is working
4) Damaged outdoor coil thermis-
tor
Auto vane motor is damaged.
Auto vane motor relay is damaged.
Refer to check code on remote controller display.
Transmission wire is damaged.
Connector is poorly connected.
1) Check the thermistor.
2) Measure the resistance of the thermistor.
Normal resistance should be as follows.
32°F····15kΩ
50°F······9.6kΩ 104°F·····3.0kΩ
68°F······6.3kΩ
If the resistance is normal, replace the indoor
controller board.
1) Check the connector.
2) Measure the resistance of the thermistor
(between
As for the normal resistance, refer to the case
of 1.
If the resistance is normal, replace the indoor con-
troller board.
1) Check the drain pump.
2) Check the drain sensor.
Check the drain sensor heater. Normal resis-
tance should be 82Ω. (between 1 - 3of
CN50).
If the resistance is normal, replace the indoor con-
troller board.
1) Clear obstructions from the air cycle.
2) Clean the air filter
3) Check the fan.
4) Check the refrigerant temperature.
1) Check the indoor/outdoor connecting wire.
2) Change the connection of electric wiring.
3) Check the protection device.
4) Measure the resistance of the outdoor coil ther-
mistor. If the resistance is normal, replace the
outdoor controller board.
42
Check points
86°F·····4.3kΩ
- of CN50).