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Fault phenomenon: The indoor display board of the cabinet machine shows P0 (IPM module fault).
Fault range: outdoor electrical control, compressor, compressor connection wire group.
Sanyo STK621-061-E module circuit
Troubleshooting steps:
Step 1:
1. Open the top cover of the outdoor unit and carefully check the outdoor electrical control compressor drive module (the module closest to the compressor connection wire group in blue, red, and black) and the resistors near the module for signs of cracking or burning.
If there are obvious signs of burning or cracking, it is determined to be an electrical control fault, and the outdoor electrical control should be replaced;
2. Check whether the U/V/W wiring on the electrical control and compressor is correct. After confirming that the wiring is correct, disconnect the connection wire group between the compressor and the electrical control, and then measure the resistance between the compressor U/V/W. The correct resistance value should be 0.5-2Ω. If the resistance value is significantly larger, disassemble the outdoor unit and test whether the compressor connection wire group is connected properly and whether it is burned. After confirming that the connection wire group is fine, measure the resistance between the compressor U/V/W. If the resistance is greater than 10Ω, it is determined to be a compressor fault, and the compressor should be replaced.
Step 2:
Disconnect the connection wire group between the compressor and the module (Note: Make sure the connection wire group between the compressor and electrical control is disconnected, and other connections remain unchanged, otherwise the measurement is meaningless), and measure the following resistance:
1. Measure the resistance between U (blue), V (red), and W (black) on the electrical control board (Note: The multimeter positive and negative probes need to measure a total of 6 combinations: UV, VU, UW, WU, VW, WV). The resistance value range is approximately: 300KΩ-800KΩ, and the resistance difference between combinations (for example, the resistance of UV and the resistance of UW) should be less than 10KΩ;If either of the following two situations occurs, it is determined to be an outdoor electrical control fault, and the outdoor electrical control should be replaced:
1) Measuring UV, VU, UW, WU, VW, WV, if any of the 6 combined resistances is less than 100KΩ or greater than 3MΩ.
2) The resistance difference between combinations (for example, the resistance of UV and the resistance of UW) is greater than 30KΩ.
2. Measure the resistance between U (blue), V (red), and W (black) on the electrical control board and P (the positive terminal of the large capacitor, there will be markings at the IPM module pin). The positive terminal of the multimeter connects to U/V/W, and the negative terminal connects to P. The measured three sets of line resistance values should not differ significantly, with a resistance range of: 200KΩ-800KΩ, and the resistance difference between combinations (for example, the resistance of UP and the resistance of VP) should be less than 10KΩ;
If either of the following two situations occurs, it is determined to be an outdoor electrical control fault, and the outdoor electrical control should be replaced:
The measured resistance is less than 50KΩ or greater than 3MΩ. The resistance difference between combinations (for example, the resistance of UP and the resistance of VP) is greater than 30KΩ.
3. Measure the resistance between U (blue), V (red), and W (black) on the electrical control board and N (the negative terminal of the large capacitor, there will be markings at the IPM module pin). The positive terminal of the multimeter connects to U/V/W, and the negative terminal connects to N. The measured three sets of line resistance values should not differ significantly, with a resistance range of: 200KΩ-800KΩ, and the resistance difference between combinations (for example, the resistance of UN and the resistance of VN) should be less than 10KΩ.
If either of the following two situations occurs, it is determined to be an outdoor electrical control fault, and the outdoor electrical control should be replaced:
The measured resistance is less than 50KΩ or greater than 3MΩ; the resistance difference between combinations (for example, the resistance of UN and the resistance of VN) is greater than 30KΩ;
4. Measure the resistance between U+, V+, W+, U-, V-, W- (six paths for compressor drive) and N (U+ with N, V+ with N, W+ with N, U- with N, V- with N, W- with N). The resistance value is approximately: 3KΩ-6KΩ, and the resistance values of each group measured should differ by less than 1KΩ.
If the following situation occurs, it is determined to be an outdoor electrical control fault, and the outdoor electrical control should be replaced:
If the measured resistance value of one of the six drives differs significantly from the others (the resistance difference is greater than 1KΩ), for example: the measured resistance value of V+ and N differs from that of W+ and N by more than 1KΩ.
Step 3:
After confirming that there are no issues in the above two measurements, turn on the power and measure the following voltages:
15V power supply: The PCB board bottom is marked. If not found, look for the outdoor electrical control board closest to the frequency conversion module (with a large heat sink, connected to the compressor connection wire group) IN4749 voltage regulator diode, measure the voltage at both ends of the voltage regulator tube to see if it meets the voltage in the above table.
|
Measurement Point |
15V Power Supply |
N line |
|
DC voltage between it and N line |
15V-17V |
0V |
If the voltage of the 15V power supply is less than 12V or greater than 18V, it is determined to be an outdoor electrical control fault, and the outdoor electrical control should be replaced;
Step 4:
If all three measurements above show no problems, refer to the frequency conversion machine performance repair manual to confirm whether there is a compressor fault.