Suction Pipe Temperature Thermistor (Th6) Open/Short; 5102 - Mitsubishi Electric PUMY-P250YBM Technical & Service Manual

Check code

Suction pipe temperature thermistor (TH6) open/short

5102

(U4)
<Detected in outdoor unit>
Abnormal points and detection methods
If TH6 detects to be open/short.
(The open/short detection is disabled during 10 seconds to 10 minutes
after compressor starts, during defrosting operation, or for 10 minutes after
returning from the defrosting operation.)
Open: −40°C or less
Short: 90°C or more TH6: Thermistor <Suction pipe>
●Diagnosis of defects
Make sure to turn the power OFF before connecting/disconnecting
any connectors, or replacing boards.
Check the wiring and connector connection of TH6.
Is there any abnormality such
as disconnection, looseness or
breakage?
Disconnect the connector to check the
resistance of TH6 using a multimeter.
Is the detected resistance normal?
Check the temperature of TH6.
Is the detected temperature normal?
OCH760
Diagnosis
No
Yes
Yes
Causes and checkpoints
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.
Yes
Replace it in the case of breakage.
No
The detected temperature of TH6 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
No
board (Malfunction of thermistor circuit).
No abnormality
( A connector contact failure is suspected.)
66
Remedy
Replace the thermistor.
Unit
°C