In this article, we’ll explain how to diagnose a common issue in inverter air conditioners: when the compressor fails to start. Follow these detailed steps to identify and resolve the problem:
1. Restart the Unit
- Turn off the air conditioner and unplug it for at least 5 minutes.
- Plug it back in, turn it on, and check if the issue persists.
2. Check the Power Supply Voltage
- Use a multimeter set to the AC voltage scale.
- Measure the voltage at the external power source.
- Ensure it is within the manufacturer’s specified range.
If the voltage is incorrect:
- Connect the unit to another power source.
- Consider using a voltage stabilizer.
3. Inspect Electrical Connections
- Check the electrical connections in the indoor unit.
- Make sure there are no loose, damaged, or improperly connected wires.
4. Examine the Outdoor Unit
- Turn off and unplug the air conditioner.
- Open the outdoor unit and locate the compressor.
- Disconnect the connector supplying power to the compressor.
5. Measure the Compressor Coil Resistance
- Set your multimeter to the ohms scale.
- Measure the resistance between each pair of compressor pins (three measurements in total).
- The values should be similar; significant differences may indicate coil issues.
6. Test the Continuity of Power Supply Cables
- Set the multimeter to continuity mode.
- Measure the electrical resistance between the compressor connector and the control board.
- The resistance should be minimal.
7. Test the Intelligent Power Module (IPM)
a. Preparation
- Disconnect the unit for several minutes to discharge the capacitors.
- Set the multimeter to diode mode.
b. First Measurement
- Place the positive probe of the multimeter on the negative polarity of the high-power capacitors.
- Use the negative probe to test the three compressor connector pins (U, V, W).
- Repeat the measurement, rotating the negative probe across the pins. The values should be consistent.
c. Second Measurement
- Switch the multimeter configuration: place the negative probe on the capacitor’s positive polarity.
- Use the positive probe to test the compressor connector pins (U, V, W).
- Repeat the process three times; the values should be uniform.
8. Check the PFC Circuit (Power Factor Correction)
- If all the previous checks are normal, the issue could be with the outdoor control board, specifically the PFC circuit.
