Troubleshooting - Mitsubishi Electric MXZ-A18WV Service Manual

12

TROUBLESHOOTING

MXZ-A18WV-
E1
MXZ-A26WV-
E1
MXZ-A32WV-
E1
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 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 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.
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 this page and the check table on page 53, 54, 55 and 56.
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.
MXZ-A18WV -
E1
MXZ-A26WV -
E1
MXZ-A32WV -
E1
Operation start
Check the outdoor unit
LED indicator.
OFF
A Check of power supply
See page 58.
• Indoor unit • COOL or
serial signal HEAT
error operation only
B Check of C Check of
serial signal R.V.coil
See page 59. See page 60.
Housing point
Lead wiring
Both LED 1 and
LED 2 lighting
• When cooling, heat
exchanger of
non-operating indoor
unit frosts.
•When heating, non-
operating indoor unit
gets warm.
D Check of LEV
See page 61.
• When cooling, • When heating,
dew drops in the room does not get
non-operating warm.
E Check of
indoor unit.
Check of mis- inverter, compressor
piping See page 62 or 63.
Check mis-piping,
shortage of capacity
52
LED 1 or LED 2
has blinked.
Refer to indicator list
on page 53,54,55 and
56.
• When cooling,
room does not
cool.
E Check of
inverter,
compressor
See page
62 or 63.