Service Functions; Change In Defrost Setting; Pre-Heat Control Setting - Mitsubishi Electric MUZ-FS06NA Service Manual

9

SERVICE FUNCTIONS

MUZ-FS06NA MUZ-FS06NAH MUZ-FS09NA MUZ-FS09NAH MUZ-FS12NA MUZ-FS12NAH
MUZ-FS15NA MUZ-FS15NAH MUZ-FS18NA MUZ-FS18NAH

9-1. CHANGE IN DEFROST SETTING

Changing defrost finish temperature
<JS> To change the defrost finish temperature, cut/solder the JS wire of the outdoor inverter P.C. board (Refer to 10-6.1.).
Jumper
Soldered
(Initial setting)
JS
None
(Cut)

9-2. PRE-HEAT CONTROL SETTING

MUZ-FS06/09/12
When moisture gets into the refrigerant cycle, it may interfere with the start-up of the compressor at low outside tempera-
ture. The pre-heat control prevents this interference. The pre-heat control turns ON when the discharge temperature ther-
mistor is 68°F (20°C) or below. When the pre-heat control turns ON, the compressor is energized. (About 50 W)
MUZ-FS15/18
Prolonged low load operation, in which the thermostat is OFF for a long time, at low outside temperature [32°F (0°C) or
less] may cause the following troubles. To prevent those troubles, activate the pre-heat control.
1) If moisture gets into the refrigerant cycle and freezes, it may interfer the start-up of the compressor.
2) If liquid refrigerant collects in the compressor, a failure in the compressor may occur.
The pre-heat control turns ON when the compressor temperature is 68°F (20°C) or below. When the pre-heat control
turns ON, the compressor is energized. (About 70 W)
Pre-heat control setting
<JK>
ON: To activate the pre-heat control, cut JK wire of the inverter P.C. board.
OFF: To deactivate the pre-heat control, solder JK wire of the inverter P.C. board.
(Refer to 10-6.1)
Jumper
Soldered
JK
Cut
NOTE: When the inverter P.C. board is replaced, check the jumper wires, and cut/solder them if necessary.
OBH873
Defrost finish temperature
MUZ-FS06/09/12NA
MUZ-FS06/09/12NAH
41°F (5°C)
50°F (10°C)
Pre-heat control setting
MUZ-FS06/09/12NA
MUZ-FS06/09/12NAH
Deactivated
(Initial setting)
Activated
MUZ-FS15/18NA
MUZ-FS15/18NAH
50°F (10°C)
64°F (18°C)
MUZ-FS15/18NA
MUZ-FS15/18NAH
Deactivated
(Initial setting)
Activated
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