Mitsubishi Electric CITY MULTI PUMY-P112VKM6 Service Manual page 57

5102 (U4): Suction pipe temperature thermistor (TH6) open/short
Abnormal points and detection methods
TH6 is found to be open/short.
(The open/short detection is disabled for 10 seconds to 10
minutes after compressor starts, during defrosting opera-
tion, or for 10 minutes after returning from the defrosting
operation.)
Open:
−40°C [−40°F] or less
Short:
90°C [194°F] or more
TH6:
Thermistor <Suction pipe>
Diagnosis of failure
Check the wiring and connector connection of
TH6.
Is there any abnormality such as
disconnection, looseness or break-
age?
Disconnect the connector to check the resis-
tance of TH6 using a multimeter.
Is the detected resistance normal?
Check the temperature of TH6.
Is the detected temperature normal?
OCH790 _57
<Detected in outdoor unit>
Yes
No
No
Yes
The detected temperature of TH6 can be displayed
by an operation of SW1 on the outdoor multi
controller circuit board.
ON
OFF
No
Yes
Causes and checkpoints
• Disconnection or contact failure of connectors
• Faulty thermistor
• Defective outdoor multi controller circuit board
Connect the wiring/connector properly.
Replace it in the case of breakage.
Replace the thermistor.
SW1 Setting Display on LED1, 2 Unit
–99.9–999.9 °C
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.)
The black square (■) indicates a switch position.