Service Functions; Troubleshooting - Mitsubishi Electric Mr.Slim MUZ-A09NA Service Manual

9

SERVICE FUNCTIONS

MUZ-A09NA MUZ-A12NA MUZ-A15NA MUZ-A17NA
CHANGE IN DEFROST SETTING
<JS> When the JS wire of the outdoor Inverter P.C. board is cut/soldered, the defrost finish temperature is changed. (Refer to
10-6.1.)
Jumper wire
Soldered (Initial setting)
JS
10

TROUBLESHOOTING

MUZ-A09NA MUZ-A12NA MUZ-A15NA MUZ-A17NA MUZ-A24NA
MUY-A15NA MUY-A17NA MUY-A24NA MUZ-GA24NA MUY-GA24NA
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.
None (Cut)
Lead wiring
Defrost fi nish temperature °F (°C)
MUZ-A09/12NA
50 (10)
55 (13)
Housing point
38
MUZ-A15/17NA
41 (5)
46 (8)