Mitsubishi Electric PK-2.5FLD Technical & Service Manual page 31

Check
Diagnosis of malfunction
code
Abnormality of room temper-
1
ature thermistor (RT1)
Abnormality of pipe tempera-
2
ture 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.
3.WHEN OUTDOOR UNIT DOES NOT WORK
1) Indoor/outdoor connecting wires are poorly connected.
(Refer to the below.)
2) Power supply is poorly connected.
3) Connector is broken.
4) Fuse (5A) in the outdoor controller board is blown.
4. WRONG WIRING ON SITE
Symptom due to wrong wiring between indoor and outdoor units
Wrong wiring
Disconnect between 1 and 1 or 2 and
2.
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
Cause
Thermostat
OFF
ON
1) Check the thermistor.
2) Measure the resistance of the thermistor.
Normal resistance should be as follows.
0: ···15kΩ
10:······9.6kΩ 40:·····3.0kΩ
20:······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 P1.
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.
1) Check the connecting wires.
2) Check the power supply.
3) Check connector.
4) Check the fuse.
Operation stops.
9 minutes later, the check code ¨P8¨ appears on the remote con-
troller display.
31
Check points
30:·····4.3kΩ
- of CN50).
Check points
Phenomena