OCH791 _47
5101 (U3): Compressor temperature thermistor (TH4) open/short
<Detected in outdoor unit>
Abnormal points and detection methods
TH4 is found 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°C [37.4°F] or less*
Short:
217°C [422.6°F] or more
TH4:
Thermistor <Compressor>
*
-10°C [14°F] or less when PEFY-P·VMH(S)-E-F is connected.
Causes and checkpoints
• Disconnection or contact failure of connectors
• Faulty thermistor
• Defective outdoor multi controller circuit board
The black square (■) indicates a switch position.
Diagnosis of failure
Connect the wiring/connector properly.
Replace the connector in the case of breakage.
Replace the thermistor.
Replace the outdoor multi controller circuit board
(Malfunction of thermistor circuit).
No abnormality
(A connector contact failure is suspected.)
Check the wiring and connector connection of
TH4.
Disconnect the connector to check the resis
-
tance of TH4 using a multimeter.
Check the temperature of TH4.
The detected temperature of TH4 can be displayed
by an operation of SW1 on the outdoor multi
controller circuit board.
Is there any abnormality such as
disconnection, looseness or break
-
age?
Is the detected resistance normal?
Is the detected temperature normal?
Yes
No
No
Yes
No
Yes
ON
OFF
1 2 3 4 5 6 7 8
SW1 Setting
Display on LED1, 2
Unit
–0.99–999.9
°C
