Mitsubishi Electric PUMY-P112VKM3 Technical & Service Manual page 77

Check code
Suction pipe temperature thermistor (TH6) open/short
5102
(U4)
<Detected in outdoor unit>
Abnormal points and detection methods
Abnormal 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 [−40°F] or less
Short: 90 [162°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 TH6.
Is there any abnormality such
as a disconnection, looseness or
breakage?
Disconnect the connector to check the
resistance of TH6 using a tester.
Is the detected resistance normal?
Check a temperature of TH6.
Is the detected temperature normal?
OCH632A
TH6: Thermistor <Suction pipe>
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.
Yes
Replace it in case of a 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.)
77
Remedy
Replace the thermistor.
Unit
: