Mitsubishi Electric PUMY-P112VKM3 Technical & Service Manual page 76

Check code
Compressor temperature thermistor (TH4) open/short
5101
(U3)
<Detected in outdoor unit>
Abnormal points and detection methods
Abnormal if TH4 detects to be open/short.
(The open/short detection is disabled for 10 minutes after compressor
starts, during defrosting operation, or for 10 minutes after returning from
the defrosting operation.)
Open: 3 [37°F] or less
Short: 217 [423°F] or more
●Diagnosis of defectives
Make sure to turn the power OFF before connecting/disconnecting
any connectors, or replacing boards.
Check the wiring and connector connection of TH4.
Is there any abnormality such
as a disconnection, looseness or
breakage?
Disconnect the connector to check the
resistance of TH4 using a tester.
Is the detected resistance normal?
Check a temperature of TH4.
Is the detected temperature normal?
OCH632A
TH4: Thermistor <Compressor>
Diagnosis
No
Yes
Yes
Causes and check points
Disconnection or contact failure of connectors
Characteristic defect of thermistor
Defective outdoor multi controller circuit board
The black square (■) indicates a switch position.
Connect the wiring/connector properly.
Replace the connector in case of a
Yes
breakage.
No
The detected temperature of TH4 can be displayed
by an operation of SW1 on the outdoor multi
controller circuit board.
SW1 Setting Display on LED1, 2
ON
−99.9–999.9
OFF
1 2 3 4 5 6 7 8
Replace the outdoor multi controller circuit
board
No
(Malfunction of thermistor circuit).
No abnormality
(A connector contact failure is suspected.)
76
Remedy
−99.9–999.9
Replace the thermistor.
Unit
: