MITSUBISHI ELECTRIC MXZ-24UV - Manual (Page 24)

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12 TROUBLESHOOTING
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 25, 26.
Lead wiring Housing point
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.
12-2. Instruction of troubleshooting
Operation start
Check the outdoor unit
LED indicator
A Check of power supply
See page 28.
• Indoor unit
serial signal
error
B Check of
serial signal
See page 28.
• Cool or HEAT
opereation only
C Check of
R.V.coil
See page 29.
• When cooling,
room does not
cool.
E Check of
inverter,
compressor
See page 30.
• When cooling, heat
exchanger of
non-operating indoor
unit frosts.
•When heating, non
operating indoor unit
gets warm.
D Check of LEV
See page 30.
• 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
See page 30.
Check mis-piping
Shortage of capacity
Refer to indicator list
See page 25, 26.
OFF
" 00 "
• 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.
Display other than " 00 "
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