Mitsubishi Electric PURY-P72 Service Handbook page 290

[ IX Troubleshooting ]
Troubleshooting according to the remote controller malfunction or the external input error
Both for MA remote controller and ME remote controller
Both for MA remote controller and ME remote controller
1. Phenomena
Although cooling operation starts with the normal remote controller display, the capacity is not enough
(1) Cause, check method and remedy
1. Compressor frequency does not rise sufficiently.
ŒFaulty detection of pressure sensor.
ŒProtection works and compressor frequency does
not rise due to high discharge temperature
ŒProtection works and compressor frequency does
not rise due to high pressure
ŒPressure drops excessively.
2. Indoor unit LEV malfunction
ŒInsufficient refrigerant flows due to LEV malfunc-
tion (not enough opening) or protection works and
compressor frequency does not rise due to pres-
sure drop.
ŒRefrigerant leak from LEV on the stopping unit
causes refrigerant shortage on the running unit.
3. RPM error of the outdoor unit FAN
ŒMotor failure or board failure, or airflow rate de-
crease due to clogging of the heat exchanger
ŒThe fan is not properly controlled as the outdoor
temperature cannot be precisely detected by the
temperature sensor.
ŒThe fan is not properly controlled as the pressure
cannot be precisely detected by the pressure sen-
sor.
HWE1116D
Cause
- 281 -
Check method and remedy
(1) Check pressure difference between the detected
pressure by the pressure sensor and the actual
pressure with self-diagnosis LED.
-> If the accurate pressure is not detected, check
the pressure sensor. (Refer to the page on Trouble-
shooting of Pressure Sensor)(page 289)
Note: Lower inlet pressure by the low pressure sensor
than the actual pressure causes insufficient capac-
ity.
SW4 setting (SW6-10: OFF)
High pressure sensor
SW4
ON
Low pressure sensor
SW4
ON
(2) Check temperature difference between the evapo-
rating temperature (Te) and the target evaporating
temperature (Tem) with self-diagnosis LED.
Note: Higher Te than Tem causes insufficient capacity.
SW4 setting (SW6-10: OFF)
Evaporating temperature Te
SW4
ON
Target evaporating temperature Tem
SW4
ON
Note: Protection works and compressor frequency does
not rise even at higher Te than Tem due to high dis-
charge temperature and high pressure.
At high discharge temperature:
Refer to 1102.(page 200)
At high pressure:
Refer to 1302.(page 202)
Refer to the page of LEV troubleshooting ([4] -5-
).(page 296)
Refer to the page on troubleshooting of the outdoor
unit fan.
Refer to 5107.(page 234)
Refer to 1302.(page 202)
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