Mitsubishi Electric City Multi CMB-WP108V-G, Service Manual

Page: 231 / 301

[
IX
Troubleshooting ]
- 222 - HWE1113B GB
(2) Inverter output related troubles
Items to be checked Phenomena Remedy
[1]
Check the
INV board er-
ror detection
circuit. (1) Disconnect the invert-
er output wire from
the terminals of the
INV board (SC-U,
SC-V, SC-W). 1) Overcurrent error
(4250 Detail code No. 101, 104,
105, 106, and 107) Replace the INV board.
(2) Put the outdoor unit
into operation. 2) Logic error
(4220 Detail code No. 111) Replace the INV board.
3) ACCT sensor circuit failure
(5301 Detail code No.117) Replace the INV board.
4) IPM open
(5301 Detail code No.119) Normal
[2]
Check for
compressor
ground fault
or coil error. Disconnect the compressor
wiring, and check the com-
pressor Meg, and coil resis-
tance. 1) Compressor Meg failure
Error if less than 1 Mohm. Check that there is no liquid re-
frigerant in the compressor.
If there is none, replace the com-
pressor.
2) Compressor coil resistance failure
Coil resistance value of 0.32 ohm
(20°C [68°F]) Replace the compressor.
[3]
Check wheth-
er the inverter
is damaged.
(No load) (1) Disconnect the invert-
er output wire from
the terminals of the
INV board (SC-U,
SC-V, SC-W). 1) Inverter-related problems are de-
tected. Connect the short-circuit connec-
tor to CN6, and go to section [1].
(2) Disconnect the short-
circuit connector from
CN6 on the INV
board. 2) Inverter voltage is not output at the
terminals (SC-U, SC-V, and SC-W) Replace the INV board.
(3) Put the outdoor unit
into operation.
Check the inverter
output voltage after
the inverter output
frequency has stabi-
lized. 3) There is an voltage imbalance be-
tween the wires.
Greater than 5% imbalance or 5V Replace the INV board.
4) There is no voltage imbalance be-
tween the wires. Normal
*Reconnect the short-circuit con-
nector to CN6 after checking the
voltage.