Title: Analysis of Repair Case (I) for Midea MDV Inverter Central Air Conditioning
Faulty Model: MDV-J160W
Symptom: After the outdoor unit's fixed-frequency system starts up for one minute, the indoor leakage current circuit breaker trips.
Analysis: It was observed that the indoor leakage current circuit breaker always tripped when the outdoor fan and compressor started. There might be a short circuit in the wiring between the indoor and outdoor units or a leakage in the outdoor unit.
Troubleshooting: Step 1: Check the signal line connections, which were found to be correct. Step 2: Inspect the compressor and fan of the outdoor unit, finding no short circuits or leakage. Thus, the fault in the air conditioner itself was ruled out. At this point, we noticed that the power supply for the indoor unit was connected separately from the outdoor unit, which does not comply with the wiring requirements for our air conditioning system. If the power lines are connected separately, the strong electrical start-up signal from the indoor unit reaches the outdoor unit and returns through the outdoor unit's leakage current circuit breaker. The difference in current between the live wire and neutral wire of the indoor unit causes the indoor leakage current circuit breaker to trip.
Case Summary: During installation, wiring must strictly follow the wiring diagram.
Beijing Midea Air Conditioning Maintenance Center
August 10, 2011