Troubleshooting; Cautions On Troubleshooting; Before Troubleshooting; Take Care Of The Following During Servicing - Mitsubishi Electric MXZ-2B20NA Service Manual

TROUBLESHOOTING

11
MXZ-2B20NA MXZ-3B24NA MXZ-3B30NA MXZ-4B36NA MXZ-5B42NA

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 unit first with the remote controller, and then after confirm-
ing 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 OPERATIONAL INDICATOR lamp is flashing on and off before starting service
work.
2) 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.
3) When troubleshooting, refer to 11-2, 11-3 and 11-4.
11-2. FAILURE MODE RECALL FUNCTION
This air conditioner can memorize the abnormal condition which has occurred once.
Even though LED indication listed on the troubleshooting check table (11-4) disappears, the memorized failure details
can be recalled.
1. Flow chart of failure mode recall function for the indoor/outdoor unit
Refer to the service manual of indoor unit.
OBH560G
<Incorrect>
Housing point
Lead wiring
<Correct>
56