Toshiba HFC R407C Service Manual page 62

Diagnostic procedure for check code
Check code
[dA]
Abnormal overheat of heat sink
Refer to outdoor unit
Is power supply voltage normal ?
Yes
Is the wiring connector
connection normal on the
inverter PC board ?
Yes
Is outdoor fan normal ?
Yes
Is there a screw loose on the
IGBT module or heat sink on
inverter PC board ?
No
Is there a blockage in the heat
sink cooling duct ?
No
Check inverter PC board.
62
Troubleshooting
Operation cause
1. Power supply failure.
2. Outdoor fan error.
3. Heat sink installation failure.
4. Blockage of heat sink cooling duct.
5. Defective inverter PC board.
No
No
No
Yes
Yes
Check power supply.
Check the circuit wiring, for example wiring to the
inverter compressor or connector connection.
Check fan and fan motor.
Tighten screws.
Remove blockage.