Mitsubishi Electric PUMY-P112VKM4 Technical & Service Manual page 66

Check code
1501
(U2)
Abnormal points and detection methods
(1) When all of the following conditions have been satisfied for 15
consecutive minutes:
1. The compressor is operating in HEAT mode.
2. Discharge superheat is 80ºC [144ºF] or more.
3. Difference between TH7 and TH3 applies to the formula of
(TH7−TH3 < 5ºC [9ºF])
4. The saturation temperature converted from a high pressure sensor
detects below 35ºC [95ºF].
(2) When all of the following conditions have been satisfied:
1. The compressor is in operation.
2. When cooling, discharge superheat is 80ºC [144ºF] or more, and
the saturation temperature converted from a high pressure sensor is
over −40ºC [−40ºF].
3. When heating, discharge superheat is 90ºC [162ºF] or more.
●Diagnosis of defects
Make sure to turn the power OFF before connecting/disconnecting any connectors, or replacing boards.
Is the outdoor stop valve (ball
valve) fully open?
Is there refrigerant leak?
Is 5104 displayed when restarted?
Check relevant thermistor wirings and
connector contacts of the outdoor multi
controller circuit board.
Is there any abnormality on
connectors such as disconnection,
half-disconnection or breakage?
Disconnect the thermistor wiring and check
the resistance.
Continue to the next page.
OCH673D
Refrigerant shortage trouble
Diagnosis
Yes
(leaking)
(no leaking)
No
(5104)
(1501)
No
No
Causes and checkpoints
Defective operation of stop valve (not fully open)
Defective thermistor
Defective outdoor multi controller circuit board
Indoor LEV performance failure
Gas leakage or shortage
Defective 63HS
TH3: Thermistor <Outdoor liquid pipe>
TH7: Thermistor <Ambient>
LEV: Linear expansion valve
63HS: High pressure sensor
Open the stop valve (ball valve) fully.
No
Yes Repair the refrigerant leak.
Refer to the diagnosis of check code 5104.
Yes
Connect the connector properly
Yes
(Repair or replace it in the case of breakage).
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Chart 1 of 2
Remedy