MITSUBISHI ELECTRIC MUY-GE09NA - Manual (Page 23)

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9-1. CHANGE IN DEFROST SETTING (MUZ)
Changing defrost finish temperature
To change the defrost finish temperature, cut/solder the JS wire of the outdoor inverter P.C. board.
(Refer to 10-6-1.)
Jumper
Defrost fi nish temperature
MUZ-GE09/12/15 MUZ-GE18
JS
Soldered
(Initial setting)
41°F (5°C) 48°F (9°C)
None
(Cut)
50°F (10°C) 64°F (18°C)
MUZ-GE09NA MUZ-GE12NA MUZ-GE15NA MUZ-GE18NA
MUY-GE09NA MUY-GE12NA MUY-GE15NA MUY-GE18NA
9-2. PRE-HEAT CONTROL SETTING
PRE-HEAT CONTROL
When moisture gets into the refrigerant cycle, it may interfere 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 outside temperature is 68°F (20
°C) or below. When pre-heat control is turned ON, compressor is energized. (About 50 W)
To activate the pre-heat control, cut the JK wire of the inverter P.C. board. (Refer to 10-6.1)
NOTE: When the inverter P.C. board is replaced, check the Jumper wires, and cut/solder them if necessary.
10 TROUBLESHOOTING
10-1. CAUTIONS ON TROUBLESHOOTING
1. Before troubleshooting, check the following
1) Check the power supply voltage.
2) Check the indoor/outdoor connecting wire for miswiring.
2. Take care of the following during servicing
1) Before servicing the air conditioner, be sure to turn OFF the main unit first with the remote controller, then after con-
firming the horizontal vane is closed, turn off the breaker and/or disconnect the power plug.
2) Be sure to turn OFF the power supply before removing the front panel, the cabinet, the top panel, and the electronic
control P.C. board.
3) When removing the electrical parts, be careful of the residual voltage of smoothing capacitor.
4) When removing the electronic control P.C. board, hold the edge of the board with care NOT to apply stress on the
components.
5) When connecting or disconnecting the connectors, hold the housing of the connector. DO NOT pull the lead wires.
3. Troubleshooting procedure
1) First, check if the OPERATION INDICATOR lamp on the indoor unit is flashing ON and OFF to indicate an abnormal-
ity. To make sure, check how many times the abnormality indication is flashing ON and OFF before starting service
work.
2) Before servicing check that the connector and terminal are connected properly.
3) When the electronic control P.C. board seems to be defective, check the copper foil pattern for disconnection and the
components for bursting and discoloration.
4) Refer to 10-2. and 10-3.
Lead wiring Housing point
MUZ-GE09NA MUZ-GE12NA MUZ-GE15NA MUZ-GE18NA
MUY-GE09NA MUY-GE12NA MUY-GE15NA MUY-GE18NA
9 SERVICE FUNCTIONS