Heat Sink Temperature Thermistor(Th8) Open/Short - Mitsubishi Electric PUMY-P200YKM Technical & Service Manual

Check code

Heat sink temperature thermistor(TH8) open/short

5110
Abnormal points and detection methods
Abnormal if TH8 detects to be open/short.
Open:−34.8 [−36.6-F] or less
Short: 102 [215.6-F] or more
TH8: Thermistor <Heat sink>
●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 TH8.
Is there any abnormality such
as a disconnection, looseness or
breakage?
Disconnect the connector to check the
resistance of TH8 using a tester.
Is the detected resistance normal?
Check a temperature of TH8.
Is the detected temperature normal?
OCH575
Diagnosis
Yes
No
No
Yes
No
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 it in case of a breakage.
Replace the thermistor.
The detected temperature of TH8 can be displayed by
The detected temperature of thermistor (TH8)
an operation of SW1 on the outdoor multi controller
can be displayed by an operation of SW1 on the
circuit board.
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
(Malfunction of thermistor circuit).
No abnormality
( A connector contact failure is suspected.)
68
Remedy
outdoor
Unit
: