Air Inlet Thermistor Trouble (Th21); Liquid Pipe Temperature Thermistor Trouble (Th22); Gas Pipe Temperature Thermistor Trouble (Th23) - Mitsubishi Electric PUMY-P112VKM1 Service Manual

Check code
5101, 5102, 5103
<Detected in indoor unit>
Abnormal points and detection methods
Abnormal if any of the following thermistor detected to be open/ short.
TH21: Air inlet thermistor
TH22: Liquid pipe temperature thermistor
TH23: Gas pipe temperature thermistor
●Diagnosis of defectives
Make sure to turn the power OFF before connecting/disconnecting any connectors, or replacing boards.
Check the connection of
thermistor wiring for looseness
or disconnection.
Is it connected properly?
Yes
Is the resistance of
the thermistor normal?*
Yes
< Thermistors for low temperature>
■ Check code and trouble
Check code Thermistor
5101 TH21
5102 TH22
5103 TH23
■ Thermistor characteristic
Turn the power OFF to remove the connector for the thermistor, then check the resistance with a tester.
(At the ambient temperature 10 to 30:)
Normal
4.3 to 9.6k"
* Symbols for thermistors and connectors may be different depending on the model. Please refer to its wiring diagram.
OCH576

Air inlet thermistor trouble (TH21)

Liquid pipe temperature thermistor trouble (TH22)

Gas pipe temperature thermistor trouble (TH23)

Diagnosis
No
No
connection
Connector
CN20 Air inlet thermistor trouble
CN44/CN21 Liquid piping temperature thermistor trouble
CN44/CN29 Gas piping temperature thermistor trouble
Abnormal
Open or short
Causes and check points
Contact failure of connectors
Characteristic defect of thermistor
Disconnection or contact failure of thermistor
Defective indoor controller board
Connect the wiring properly.
Replace the indoor controller board.
Trouble
82
Remedy
Replace the thermistor.