Mitsubishi Electric CITY MULTI PUHY-P108 Service Handbook page 256

Error definition and error
Error Code
4220 Bus voltage If Vdc 150V or less is de-
4225 drop tected during Inverter op-
(Detail code eration. (S/W detection)
108)
If Vdc 425V or more is
Bus voltage rise
(Detail code 109)
detected during inverter
operation.
Abnormal VDC Bus voltage abnormality If Vdc
(Detail code 110) 400V or more or Vdc 160V or
less is detected. (H/W detec-
tion)
Refer to section -8-"Inverter " under part [4] "Trouble shooting principal parts" for error codes related to the inverter.
detection method
(1) Power supply environment
(2) Voltage drop detected
(3) Main board failure
(4) 52C1 failure
(5) Diode stack failure
(1) Different voltage connection
(2) INV board failure
Same as detail code No.108
and 109 of 4220 error
- 247 -
Cause Check method and remedy
Check whether the unit makes an instanta-
neous stop when the detection result is ab-
normal or a power failure occurs.
Check whether the power voltage is 150V or
less across all phases.
In the case of 4220
Measure voltages of the male
connector (CNDC2) on the
compressor INV board.
-> Replace the INV board when
there is no voltage drop.
-> Check the followings when
there is a voltage drop.
1) Check the voltage of CN52C1 on
the main board.
Refer to (3).
2) Check whether 52C1 works normally
Refer to (4).
Or check 52C1 connecting piping.
3) Check for the diode stack.
Refer to (5).
4) Check for the wiring and the con-
nectors between the CNDC2-G
on the compressor INV board
and the CNDC1 on the G/A
board.
Replace G/A board when no fault is
found for the above (1) - (4).
In the case of 4225
Check the following.
1) Check the voltage of CN52C1 on the
main board.
Refer to (3).
2) Check whether 52C1 works normally
Refer to (4).
Or check 52C1 wire connection.
3) Check for diode stack failure.
Refer to (5).
4) Check the wiring and the connectors of
the CNVDC on the FAN INV board.
Replace FAN INV board when no
fault is found for the above (1) - (4).
Check whether AC208/230V is applied to
the male connector (CN52C1) on the main
board during inverter operation.
->If not applied, check the main board
and the fuse (F01 andF02).
Replace the main board when no
fault is found.
Refer to 9 [4]-8-(4) and check the
coil resistance check.
Refer to 9 [4]-8-(6) and check the di-
ode stack resistance.
Check the power supply voltage on the pow-
er supply terminal block (TB1).
Replace the INV board when no fault is
found.
In the case of 4220: Compressor INV board
In the case of 4225: FAN INV board
Same as detail code No.108 and
109 of 4220 error.
[ IX Troubleshooting ]