Mitsubishi Electric PQHY-P72TYHMU-A Service Handbook page 344

[ IX Troubleshooting ]
[YHMU-A]
(2) Inverter output related troubles
Items to be checked
[1] (1) Disconnect the invert-
Check the er output wire from
INV board er- the terminals of the
ror detection INV board (SC-U,
circuit. SC-V, SC-W).
(2) Put the heat source
unit into operation.
[2] Disconnect the compressor
Check for wiring, and check the com-
compressor pressor Meg, and coil resis-
ground fault tance.
or coil error.
[3] (1) Disconnect the invert-
Check wheth- er output wire from
er the inverter the terminals of the
is damaged. INV board (SC-U,
(No load) SC-V, SC-W).
(2) Disconnect the short-
circuit connector from
CN6 on the INV
board.
(3) Put the heat source
unit into operation.
Check the inverter
output voltage after
the inverter output
frequency has stabi-
lized.
[4] Put the heat source unit into
Check wheth- operation.
er the inverter Check the inverter output
is damaged. voltage after the inverter
(During com- output frequency has stabi-
pressor oper- lized.
ation)
HWE09080
Phenomena
1) Overcurrent error
Error code: 4250
Detail code: No. 101, 104, 105,
106, and 107
2) Logic error
Error code: 4220
Detail code: No. 111
3) ACCT sensor circuit failure
Error code: 5301
Detail code: No.117
4) IPM open
Error code: 5301
Detail code: No.119
1) Compressor Meg failure
Error if less than 1 Mohm.
2) Compressor coil resistance failure
Coil resistance value of 1 ohm
(20°C [68°F])
1) Inverter-related problems are de-
tected.
2) Inverter voltage is not output at the
terminals (SC-U, SC-V, and SC-W)
3) There is an voltage imbalance be-
tween the wires.
Greater than 5% imbalance or 5V
4) There is no voltage imbalance be-
tween the wires.
1) There is an voltage imbalance be-
tween the wires.
Greater than 5% imbalance or 5V
- 335 -
Remedy
Replace the INV board.
Replace the INV board.
Replace the INV board.
Normal
Check that there is no liquid re-
frigerant in the compressor.
If there is none, replace the com-
pressor.
Replace the compressor.
Connect the short-circuit connec-
tor to CN6, and go to section [1].
Replace the INV board.
Replace the INV board.
Normal
*Reconnect the short-circuit con-
nector to CN6 after checking the
voltage.
Replace the INV board.
GB