Mitsubishi Electric MXZ-4C36NAHZ Service Manual page 43

Check code
1302
Abnormal points and detection methods
(1) High pressure abnormality (63H operation)
Abnormal if 63H operates(*) during compressor operation. (*4.15 MPa)
(2) High pressure abnormality (63HS detected)
Abnormal if a pressure detected by 63HS exceeds 4.15 MPa during
compressor operation.
63H : High-pressure switch
63HS : High-pressure sensor
LEV : Electronic expansion valve
SV1 : Solenoid valve
TH7 : Thermistor <Ambient>
●Diagnosis of defectives
Make sure to turn the power OFF before connecting/disconnecting any connectors, or replacing boards.
Is 5201 displayed when restarted?
Is the outdoor stop valve (liquid/
gas) fully open?
Does the outdoor fan rotate while
the operation?
Does the indoor fan rotate while
the operation?
Is the indoor unit short-cycled?
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OCH573
High pressure trouble
Diagnosis
(5201)
(1302)
No
Yes
Yes
Yes
(short-cycled)
(no short-cycle)
No
Causes and check points
Defective operation of stop valve (not fully open)
Clogged or broken pipe
Malfunction or locked outdoor fan motor
Short-cycle of outdoor unit
Dirt of outdoor heat exchanger
Remote controller transmitting error caused by noise interference
Contact failure of the outdoor controller board connector
Defective outdoor controller board
Short-cycle of indoor unit
Decreased airflow, clogged filter, or dirt on indoor unit.
Malfunction or locked indoor fan motor
Decreased airflow caused by defective inspection
of outdoor temperature thermistor (It detects lower
temperature than actual temperature.)
Indoor LEV performance failure
Malfunction of fan driving circuit
SV1 performance failure
Defective high-pressure sensor
Defective high-pressure sensor input circuit on
outdoor controller board
Refer to the diagnosis of check code 5201.
Yes
Open the stop valve (liquid/ gas) fully.
No
Check the outdoor fan motor.
Refer to "How to check the parts" on the
No
outdoor unit service manual.
Check the indoor fan motor.
No Refer to "How to check the parts" on the
indoor unit servive manual.
Yes
43
Chart 1 of 4
Remedy
Solve the short-cycle.