Mitsubishi Electric CMB-WM108V-AA Service Handbook page 187

[ VIII 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.
Faulty detection of pressure sensor.
Protection works and compressor frequency does
not rise due to high discharge temperature
Protection works and compressor frequency does
not rise due to high pressure
Pressure drops excessively.
2. HBC controller LEV1 and 2 actuation failure
Insufficient refrigerant flows due to LEV malfunc-
tion (not enough opening) or protection works and
compressor frequency does not rise due to pres-
sure drop.
ON
1 2 3 4 5 6 7 8 9 10
HWE1708A
Cause
The figure at left shows that the switches 1 through 5 are set to ON and 6 through 10 are set to OFF.
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 in outdoor unit service
handbook)
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
Low pressure sensor
(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
Target evaporating temperature Tem
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 in outdoor unit service handbook
At high pressure:
Refer to 1302 in outdoor unit service handbook
Refer to the page of LEV troubleshooting ([4] -1-
).(page 186)
- 178 -
SW4
ON
1 2 3 4 5 6 7 8 9 10
SW4
ON
1 2 3 4 5 6 7 8 9 10
SW4
ON
1 2 3 4 5 6 7 8 9 10
SW4
ON
1 2 3 4 5 6 7 8 9 10
GB