Compressor overcurrent interruption

What does UP mean?

Compressor overcurrent is detected after 30 seconds of compressor operation, indicating an excessive current draw. Potential causes include a closed stop valve, insufficient power supply voltage, incorrect compressor wiring, fan malfunctions, short cycling, or a defective compressor or outdoor controller board input circuit. This fault protects the compressor from immediate damage but requires prompt resolution to prevent component failure.

Additional Steps

Steps 1–2 are listed in Priority Fix.

1. 3

   Inspect compressor wiring (U·V·W phase) for looseness, disconnection, or incorrect polarity. Refer to Section 10-9.

2. 4

   Verify proper operation of indoor/outdoor fans and resolve any short cycling issues.

3. 5

   Check the compressor for proper operation. Refer to Section 10-6. Before replacing the outdoor controller board, disconnect compressor wiring and check U-V, V-W, W-U phase output voltages during test run; they should be equal at the same frequency.