Mitsubishi Electric CITY MULTI PUHY-P108 Service Handbook page 279

[ IX Troubleshooting ]
-2- PURY
1. Mechanical system
Error Code
0403 Serial commu-
nication error
Refer to section -8- "Inverter " under part [4] "Trouble shooting principal parts" for error codes related to the inverter.
Error definition and error
detection method
Serial communication er- (1) Faulty wiring
ror between the main
board and the INV board
on the compressor, and
between the main board
and the INV board on the
fan
Detail code 01:
Between the main board
and the compressor INV
board
Detail code 05:
Between the main board
(2) Inverter address switch
and the FAN INV board
(3) Transformer failure
(4) Compressor INV board
Cause
setting error
failure
FAN INV board failure.
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Check method and remedy
Check for wiring between the male
connector (CNRS3B) on the main
board and the male connector
(CNRS1) on the compressor INV
board or between the male connec-
tor (CNRS3A) on the main board
and the male connector (CNRS2) on
the FAN INV board and check for
contact of the connectors.
Check for contact of the connector
(CNAC3) on the main board or of the
connector (CNTR) on the FAN INV
board.
Check the setting for SW2-1 on the
inverter board on the compressor.
Confirm that the SW2-1 on the fan
inverter board is set to ON.
Measure voltages between pins 1
and 3 of the male connector (CNTR)
on the FAN INV board.
Replace the compressor INV board
or the FAN INV board when the pow-
er turns on automatically, even if the
power source is reset.