Mitsubishi Electric PU(H)Y-P250YGM-A, Service Handbook

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[
IX
Troubleshooting ]
(2) In case of main remote controller
Phenomena Cause Check method and remedy
1 Although cooling operation
starts with the normal remote
controller display, the capacity
is not enough 1.Compressor frequency does not
rise sufficiently.
ΠWrong detection of the tempera-
ture of TH22 (Te)
ΠCompressor frequency is
limited due to high discharge
temperature
ΠCompressor frequency is
limited due to high pressure
ΠPressure drops excessively.
(1) Check the pressure difference between
the inlet temperature (TH22) and the
actual temperature by monitoring with
LED.
->If the accurate inlet temperature is
not detected, check the thermistor (Re-
fer to the page on error code 5102.).
Note: Lower inlet temperature (TH22)
than the actual temperature
causes insufficient capacity
(2) Check temperature difference between
the evaporating temperature (Te) and
the target evaporating temperature
(Tem) with self-diagnosis LED.
Note: Higher Te than Tem causes in-
sufficient capacity.
SW1 setting
Note: Protection works and compres-
sor frequency does not rise even
at higher Te than Tem due to high
discharge temperature and high
pressure.
At high discharge temperature:
Refer to 1102.
At high pressure: Refer to 1302.
2.Indoor unit LEV malfunction
ΠInsufficient refrigerant flows due
to LEV malfunction (not enough
opening) or protection works and
compressor frequency does not
rise due to pressure drop.
Refer to the page of LEV troubleshooting (9.
[4] -5- ).
3.RPM error of the outdoor unit FAN
(Only for air-cooled outdoor units)
ΠMotor failure or board failure, or
airflow rate decrease due to clog-
ging of the heat exchanger
ΠThe fan is not properly con-
trolled as the outdoor tempera-
ture cannot be precisely
detected by the temperature
sensor.
ΠThe fan is not properly con-
trolled as the pressure cannot
be precisely detected by the
pressure sensor.
Refer to the page on troubleshooting of the
outdoor unit fan.
Refer to 5106.
Refer to 1302.
1 2 3 4 5 6 7 8 9 10
Evaporating temperature Te
Target evaporating temperature Tem
ON
1 2 3 4 5 6 7 8 9 10
ON