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88
15.4.30. F99 (Output Over Current Detection)
Malfunction Decision Conditions
During operation of cooling and heating, when an output over-current (DC peak current value at IPM Prevention Control) is
detected by checking the current that flows in the inverter DC peak sensing circuitry.
detected by checking the current that flows in the inverter DC peak sensing circuitry.
Malfunction Caused
• Faulty outdoor unit PCB
• Faulty compressor
• Faulty compressor
Troubleshooting
• Checking the power transistor
• Never touch any live parts for at least 10 minutes after turning off the circuit breaker.
• If unavoidable necessary to touch a live part, make sure the power transistor’s supply voltage is below 50V using the tester.
• For the UVW, make measurement at the Faston terminal on the board of the relay connector.
• Never touch any live parts for at least 10 minutes after turning off the circuit breaker.
• If unavoidable necessary to touch a live part, make sure the power transistor’s supply voltage is below 50V using the tester.
• For the UVW, make measurement at the Faston terminal on the board of the relay connector.
Tester’s negative terminal
Power transistor (+)
UVW
Power transistor (-)
UVW
Tester’s positive terminal
UVW
Power transistor (+)
UVW
Power transistor (-)
Normal resistance
Several k
: to several M:
Abnormal resistance
0 or
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