MXZ-SM42NAMHZ Service Manual

67
OCH789
Check code
1501
(U2)
Refrigerant shortage trouble
Abnormal points and detection methods Causes and checkpoints
(1) When all of the following conditions have been satised for 15
consecutive minutes:
1. The compressor is operating in HEAT mode.
2. Discharge super heat is 176°F [80 ] or more.
3. Di󰀨erence between TH7 and the TH3 applies to the formula of
(TH7−TH3 < 9°F [5 ]).
4.The saturation temperature converted from a high pressure sensor
detects below 95°F [35 ].
(2) When all of the following conditions have been satised:
1.The compressor is in operation.
2.When cooling, discharge superheat is 144 °F [ 80 ] or more, and the
saturation temperature converted from a high pressure sensor is over
−40 °F [ −40 ].
When heating, discharge superheat is 162°F [90 ] or more.
Defective operation of stop valve (not fully open)
Defective thermistor
Defective outdoor controller 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
●Diagnosis of defects
Make sure to turn the power OFF before connecting/disconnecting any connectors, or replacing boards.
Diagnosis Remedy
Chart 1 of 2
Yes
No
No
No
No
Yes
Yes
Yes
Is the outdoor stop valve (ball
valve) fully open?
Is there refrigerant leak?
Is 5104 displayed when restarted?
Is there any abnormality on
connectors such as disconnection,
half-disconnection or breakage?
Refer to the diagnosis of check code 5104.
Check relevant thermistor wirings and
connector contacts of the controller
boards.
Disconnect the thermistor wiring and check
the resistance.
Open the stop valve (ball valve) fully.
Repair the refrigerant leak.
Connect the connector properly
(Repair or replace it in the case of
breakage).
(leaking)
(5104)
(no leaking)
(1501)
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