Mitsubishi Electric MXZ-2B30VA, Service Manual

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TROUBLESHOOTING 11
3. Troubleshooting procedure
1) First, 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 serv-
ice 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) Refer to 11-2, 11-3 and 11-4.
Lead wiring
Housing point
<Incorrect>
<Correct>
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 after confirming
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.
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.
This mode is very useful when the unit needs to be repaired for the abnormality which does not recur.
1. Flow chart of failure mode recall function for the indoor/outdoor unit
Refer to the service manual of indoor unit.
MXZ-2B30VA MXZ-2B40VA MXZ-2B52VA MXZ-3B54VA MXZ-3B68VA MXZ-4B71VA
MXZ-4B80VA MXZ-5B100VA
OBH554D