22
10-1. 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
11-6-1.)
Jumper wire
Defrost fi nish temperature (
°C
)
MUZ-GF
60VE
71VE
JS
Soldered (Initial setting)
10
10
None (Cut)
18
18
10-2. PRE-HEAT CONTROL SETTING
PRE-HEAT CONTROL
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 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 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 11-6.1)
NOTE:
When the inverter P.C. board is replaced, check JK wire, and cut/solder it if necessary.
MUZ-GF60VE MUZ-GF71VE
SERVICE FUNCTIONS
10
11-1. 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, and 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) Check if the OPERATION INDICATOR lamp on the indoor unit is flashing on and off to indicate an abnormality. To
make sure, check how many times the OPERATION INDICATOR lamp 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 11-2 and 11-3.
Lead wiring
Housing point
<Incorrect>
<Correct>
MUZ-GF60VE MUZ-GF71VE
TROUBLESHOOTING
11
OBH635
