Mitsubishi Electronics MXZ-32SV service manual Troubleshooting, Instruction of troubleshooting

12 TROUBLESHOOTING

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 mis-wiring.

2.Take care the following during servicing.

1)Before servicing the air conditioner, be sure to first turn off the remote controller to stop the unit, and then after con- firming the horizontal vane is closed, turn off the breaker and / or disconnect the power plug.

2)Be sure to unplug the power cord before removing the front panel, the cabinet, the top panel, and the electronic con- trol P.C. board.

3)When removing the electronic control P.C. board, hold the edge of the board with care NOT to apply stress on the components.

4)When connecting or disconnecting the connectors, hold the housing of the connector. DO NOT pull the lead wires.

Lead wiring Housing point

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 is supposed to be defective, check the copper foil pattern for disconnection and the components for bursting and discoloration.

3)When troubleshooting, refer to the flow chart on page 123, 124 and the check table on page 125~127.

12-2. Instruction of troubleshooting

•Check the indoor unit with referring to the indoor unit service manual, and confirm that there is any problem in the indoor unit. Then, check the outdoor unit with referring to this page.

Operation start

Check the outdoor unit LED indicator

OFF

" "

Display other than " "

ACheck of power supply on page 29.

Refer to indicator list on page 26, 27.

•Indoor unit serial signal

error

B Check of serial signa on page 29.

•Cool or HEAT

opereation only C Check of R.V.coil

on page 30.

•When cooling, heat exchanger of non-operating indoor unit frosts.

•When heating, non operating indoor unit

gets warm.

D Check of LEV on page 31.

•When cooling, dew drops in the non-operating indoor unit Check of mis- piping.

•When heating, room doed not get

warm.

E Check of inverter,compressor on page 31.

Check mis-piping Shortage of capacity

•When cooling, room does not

cool.

E Check of inverter, compressor on page 31.

25