Checking The Inverter For Damage At No-Load - Mitsubishi Electric PUHY-P250YNW-A Service Handbook

[8-9 Troubleshooting Inverter Problems ]
8-9-4

Checking the Inverter for Damage at No-Load

Items to be checked
(1) Stop the unit.
Remove power supply.
(2) Disconnect the inverter
output wires from the
compressor terminals (U,
*1
V, W).
(3) Set SW7-1 on the MAIN
board to ON.
(4) Apply power supply.
(5) Put the outdoor unit into
operation.
Check the inverter output
voltage after the inverter
output frequency has sta-
bilized.
*1 Output voltage is present at the inverter output wiring terminal. To avoid short-circuiting and ground fault, do not let the
terminal come in contact with the unit or the compressor, and use caution not to damage the terminal.
*2 Compressors on P200, P250, and P300 models are located in the back of the MAIN BOX. To disconnect the inverter output
wiring, move the MAIN BOX out of the way first, and then disconnect the wiring from the terminal on the compressor. Refer
to [8-12-1 Ensuring Maintenance Space (Preparation for the Maintenance of Refrigerant Circuit Parts)]for how to move the
MAIN BOX.
28
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Phenomena
1) Inverter-related problems are detected.
2) Inverter voltage is not output at the termi-
nals (U, V, and W)
3) There is an voltage imbalance between
the wires.
Greater than 5% imbalance or 5V
4) There is no voltage imbalance between
the wires.
Remedy
Set SW7-1 on the MAIN board to ON,
and go to [8-9-2 Checking the Inverter
Board Error Detection Circuit].
Replace the INV board.
Replace the INV board.
Normal
*When done checking, set SW7-1 on
the MAIN board back to as it was.
BS_08_C