Service Functions - Mitsubishi Electric MUZ-LN25VGHZ Service Manual

11

SERVICE FUNCTIONS

MUZ-LN25VGHZ MUZ-LN35VGHZ MUZ-LN50VGHZ
11-1. 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 12-6.1)
Jumper wire
Soldered (Initial setting)
JS
None (Cut)
11-2. PRE-HEAT CONTROL SETTING
PRE-HEAT CONTROL
MUZ-LN25/35
When moisture gets into the refrigerant cycle, it may interfere the startup of the compressor at low outside temperature.
The pre-heat control prevents this interference. The pre-heat control turns ON when the discharge temperature thermis-
tor is 20°C or below. When the pre-heat control turns ON, the compressor is energized. (About 50 W)
MUZ-LN50
Prolonged low load operation, in which the thermostat is OFF for a long time, at low outside temperature (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 interfere the startup 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 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 the JK wire of the inverter P.C. board.
OFF: To deactivate the pre-heat control, solder the JK wire of the inverter P.C. board.
(Refer to 12-6.1)
NOTE: When the inverter P.C. board is replaced, check the jumper wires, and cut/solder them if necessary.
OBH768
Defrost fi nish temperature (°C)
MUZ-LN25/35VGHZ
5
10
29
MUZ-LN50VGHZ
10
18