15.4.22. F99 (Output Over Current Detection)
Malfunction Decision Conditions
During operation of cooling and heating, when an output
Malfunction Caused
•DC peak due to compressor failure.
•DC peak due to defective power transistor(s).
•DC peak due to defective outdoor unit PCB.
Troubleshooting
20.2A?
•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.
Tester’s negative terminal | Power transistor (+) | UVW |
| Power transistor | UVW |
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Tester’s positive terminal | UVW | Power transistor (+) |
| UVW | Power transistor |
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Normal resistance |
| Several k�to several M� |
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Abnormal resistance |
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| 0 or |
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66
