Mitsubishi Electric City Multi CMB-P1016NU-G, Service Handbook

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[
IX
Troubleshooting ]
Refer to section -7- "Inverter " under part [4] "Trouble shooting principal parts" for error codes related to the inverter.
4220 Bus voltage
drop
(Detail code
108) If Vdc 150V or less is de-
tected during Inverter op-
eration. (S/W detection) (1) Power supply environment
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.
(2) Voltage drop detected
Measure voltages of the male connec-
tor (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 CN52C on the
main board.
Refer to (3).
2) Check whether 52C works nor-
mally.
Refer to (4) or check 52C con-
necting piping.
3) Check for the diode stack.
Refer to (5).
4) Check the wiring and the connectors
between the CNDC2-G on the com-
pressor INV board and the CNDC1 on
the G/A board.
Replace G/A board when no fault is
found for the above 1) - 4).
(3) Main board failure Check whether AC208 / 230 V is ap-
plied to the male connector (CN52C)
on the main board during inverter oper-
ation.
-> If not applied, check the main board
and the fuse (F01 andF02). Re-
place the main board when no fault
is found.
(4) 52C failure Refer to 9 [4] -7- (4) and check the
coil resistance check.
(5) Diode stack failure Refer to 9 [4] -7- (6) and check the
diode stack resistance.
Bus voltage
rise
(Detail code
109) If Vdc 425V or more is
detected during inverter
operation. (1) Different voltage connec-
tion
Check the power supply voltage on the
power supply terminal block (TB1).
(2) INV board failure If no problems are found with the power
supply, replace the compressor INV board.
Abnormal VDC
(Detail code
110) Bus voltage abnormality If
Vdc 400V or more or Vdc
160V or less is detected.
(H/W detection) Same as detail code No.108
and 109 of 4220 error. Same as detail code No.108 and
109 of 4220 error.
Error Code
Error definition and error
detection method
Cause Check method and remedy