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31
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
Defrost
fi
nish temperature
MUZ-HE09
MUZ-HE12
MUZ-HE15
MUZ-HE18
MUZ-HE18/24
JS
Soldered
(Initial setting)
41°F (5°C)
50°F (10°C)
41°F (5°C)
48°F (9°C)
50°F (10°C)
None
(Cut)
46°F (8°C)
55°F (13°C)
50°F (10°C)
64°F (18°C)
64°F (18°C)
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 temperature.
The pre-heat control prevents this interference. The pre-heat control turns ON when the discharge temperature thermistor
is 68°F (20°C) or below. When pre-heat control turns ON, compressor is energized. (About 50 W)
Pre-heat control setting
<JK> ON: To activate the pre-heat control, cut the JK wire of the inverter P.C. board. (Refer to 10-6.1.)
OFF: To deactivate the pre-heat control, solder 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.
9
SERVICE FUNCTIONS
MUZ-HE09NA MUZ-HE12NA MUZ-HE15NA MUZ-HE18NA MUZ-HE24NA
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) 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 10-2. and 10-3.
<Correct>
Lead wiring
Housing point
<Incorrect>
MUZ-HE09NA MUZ-HE12NA MUZ-HE15NA MUZ-HE18NA MUZ-HE24NA
OBH686
Summary of Contents for MUZ-HE09NA
Page 10: ...10 MUZ HE09NA MUZ HE12NA 5 WIRING DIAGRAM MUZ HE15NA OBH686 ...
Page 11: ...11 MUZ HE18NA OBH686 ...
Page 12: ...12 MUZ HE24NA OBH686 ...
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