Mitsubishi Electric MXZ-2A20NA-1, Service Manual

Page: 40 / 88

TROUBLESHOOTING
40
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 abnormality indication is flashing on and off before starting service work.
2) If the electronic control P.C. board seems to be defective, check the copper foil pattern for disconnection and the com-
ponents for bursting and discoloration.
3) When troubleshooting, refer to 11-2, and 11-3. and 11-4.
Lead wiring
Housing point
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 mis-wiring.
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 to 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.
MXZ-2A20NA MXZ-2A20NA - MXZ-3A30NA MXZ-3A30NA -
1 1
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 doesn’t recur.
1. Type of failure mode recall function
There are 2 types in failure mode recall function as shown below.
1
Indoor and outdoor unit failure mode recall function
With this function, failure mode of indoor unit and a part of failure mode of outdoor unit can be recalled.
2
The details of outdoor unit failure mode recall function
With this function, more detailed failure mode of outdoor unit can be recalled.
Refer to the service manual of indoor unit for how to recall the failure mode and the details of indoor unit failure mode.
The outdoor unit failure mode is indicated by the operation indicator lamp on the indoor unit and the LED of outdoor unit.
See "11-2.2. Failure mode table".
OB444B--2.qxp 07.4.17 4:33 PM Page 40