Mitsubishi PUHY-EP250 - Units in the Heating Mode Do Not Operate at Expected Capacity

[8-3 Refrigerant Control Problems ]
- 217 -
HWE12050 GB
8 Troubleshooting Based on Observed Symptoms
8-3-2 Units in the Heating Mode Do Not Operate at Expected Capacity.
1. Phenomena
Although heating operation starts with the normal remote controller display, the capacity is not enough.
2. 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 temperature
Protection works and compressor frequency does
not rise due to high pressure.
(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 following page(s). [8-5-1 Comparing
the High-Pressure Sensor Measurement and
Gauge Pressure](page 223)
Note: Higher inlet pressure by the high pressure sensor
than the actual pressure causes insufficient capac-
ity.
SW4 setting (SW6-10: OFF)
For how to read the SW settings, refer to the fol-
lowing page(s). [9-1-1 How to Read the
LED](page 253)
(2) Check the difference between the condensing tem-
perature (Tc) and the target condensing tempera-
ture (Tcm) with self-diagnosis LED.
Note: Higher Tc than Tcm causes insufficient capacity.
SW4 setting (SW6-10: OFF)
For how to read the SW settings, refer to the fol-
lowing page(s). [9-1-1 How to Read the
LED](page 253)
Note: Protection works and compressor frequency does
not rise even at lower Tc than Tcm due to high dis-
charge temperature and high pressure.
At high discharge temperature:
Refer to the following page(s).[7-3-1 Error Code
[1102]](page 149)
At high pressure:
Refer to the following page(s).[7-3-3 Error Code
[1302] (during operation)](page 151)
High pressure sensor
Low pressure sensor
ON
1 2 3 4 5 6 7 8 9 10
ON
1 2 3 4 5 6 7 8 9 10
SW4
SW4
Condensing temperature Tc
Target condensing temperature Tcm
ON
ON
1 2 3 4 5 6 7 8 9 10
1 2 3 4 5 6 7 8 9 10
SW4
SW4