Mitsubishi Electric City Multi PURY-EM200YNW-A1, Service Handbook

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[8-3 Refrigerant Control Problems ]
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8-3 Refrigerant Control Problems
8-3-1 Units in the Cooling Mode Do Not Operate at Expected Capacity.
1. Phenomena
Although cooling operation starts with the normal remote controller display, the capacity is not enough.
(1) Cause, check method and remedy
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 tempera-
ture
 Protection works and compressor frequency
does not rise due to high pressure
 Pressure drops excessively.
(1) Check pressure difference between the detected pressure by
the pressure sensor and the actual pressure with self-diagno-
sis LED.
-> If the accurate pressure is not detected, check the pres-
sure sensor.
Refer to the following page(s). [8-5-1 Comparing the High-
Pressure Sensor Measurement and Gauge Pressure]
Note: Lower inlet pressure by the low pressure sensor than the ac-
tual pressure causes insufficient capacity.
SW4 setting (SW6-10: OFF)
(2) Check temperature difference between the evaporating tem-
perature (Te) and the target evaporating temperature (Tem)
with self-diagnosis LED.
Note: Higher Te than Tem causes insufficient capacity.
SW4 setting (SW6-10: OFF)
Note: Protection works and compressor frequency does not rise
even at higher Te than Tem due to high discharge tempera-
ture and high pressure.
At high discharge temperature:
Refer to the following page(s). [7-3-1 Error Code [1102]]
At high pressure:
Refer to the following page(s). [7-3-3 Error Code [1302]
(during operation)]
2. HBC LEV1 and 2 actuation failure Refer to the following page(s). [8-8-2 General Overview on
LEV Operation (HBC)]
 Insufficient refrigerant flows due to LEV mal-
function (not enough opening) or protection
works and compressor frequency does not rise
due to pressure drop.
High pressure sensor
Low pressure sensor
SW4
SW4
ON
1 2 3 4 5 6 7 8 9 10
ON
1 2 3 4 5 6 7 8 9 10
SW4
SW4
ON
1
2 3 4 5 6 7 8 9 10
ON
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
The figure at left shows that the switches 1 through 5 are set to ON and 6 through 10 are set to OFF.
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