Mitsubishi Electric Mr.Slim MSY-D30NA, Service Manual, Page: 55 / 214

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MUZ-D30NA MUZ-D36NA MUY-D30NA MUY-D36NA
9-1. PRE-HEAT CONTROL
If moisture gets into the refrigerant cycle, or when refrigerant is lique fi ed and col-
lected in the compressor, it may interfere the start-up of the compressor.
To improve start-up condition, the compressor is energized even while it is not
operating.
This is to generate heat at the winding.
The compressor uses about 50 W when pre-heat control is turned ON.
Pre-heat control is OFF at initial setting.
[How to activate pre-heat control]
1. Turn OFF the power supply for the air conditioner before making the setting.
2. Set the 2nd Dip Switch of SW1 on the outdoor electronic control P.C. board to
ON to activate pre-heat control function.
1 2 3 4
ON
9-2. CHANGE IN DEFROST SETTING
Changing defrost finish temperature
1. Turn OFF the power supply for the air conditioner before making the setting.
2. Set the 4th Dip Switch of SW1 on the outdoor electronic control P.C. board to
ON to change the defrost finish temperature. (Refer to 10-6-1.)
4th Dip Switch of SW1 Defrost fi nish temperature
OFF
(Initial setting)
49.5°F (9.7°C)
ON 64.9°F (18.3°C)
1 2 3 4
ON
9
SERVICE FUNCTIONS