Troubleshooting - Mitsubishi Electric MXZ-2C20NA2 Service Manual

12

TROUBLESHOOTING

MXZ-3C24NA MXZ-3C30NA
MXZ-2C20NA2 MXZ-3C24NA2
MXZ-2C20NA3 MXZ-3C24NA3
MXZ-2C20NA4 MXZ-3C24NA4
MXZ-2C20NAHZ MXZ-3C24NAHZ
MXZ-2C20NAHZ2 MXZ-3C24NAHZ2 MXZ-3C30NAHZ2
MXZ-2C20NAHZ3 MXZ-3C24NAHZ3 MXZ-3C30NAHZ3
MXZ-2C20NAHZ4 MXZ-3C24NAHZ4 MXZ-3C30NAHZ4
12-1. 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 outdoor con-
trol 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 connector housing. DO NOT pull the lead wires.
3. Troubleshooting procedure
1) Check if the OPERATION INDICATOR lamp on the indoor unit is blinking on and off to indicate an abnormality. To make
sure, check how many times the OPERATIONAL INDICATOR lamp is blinking on and off before starting service work.
2) When the outdoor control P.C. board seems to be defective, check for disconnection of the copper foil pattern and burnt
or discolored components.
3) When troubleshooting, refer to 12-2, 12-3 and 12-4.
12-2. 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 (12-4) 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.
OBH702N
MXZ-4C36NA
MXZ-3C30NA2
MXZ-3C30NA3
MXZ-3C30NA4
MXZ-3C30NAHZ
<Incorrect>
Connector housing
Lead wiring
MXZ-5C42NA
MXZ-4C36NA2
MXZ-4C36NA3
MXZ-4C36NA4
<Correct>
110
MXZ-5C42NA2
MXZ-5C42NA3
MXZ-5C42NA4