Power Module Abnormality

What does U6 mean?

An abnormality is detected in the power module, often signaled by overcurrent during module operation (which can trigger UF or UP errors). This critical fault can be caused by a closed outdoor stop valve, low power supply voltage, incorrect or loose compressor wiring, or a defective compressor or outdoor power circuit board.

Additional Steps

Steps 1–2 are listed in Priority Fix.

1. 3

   Correct the wiring (U, V, W phase) to the compressor if any connections are loose, disconnected, or conversed.

2. 4

   Check the compressor for defects, referring to diagnostic procedures in section 10-6 of the manual.

3. 5

   If the above steps do not resolve the issue, replace the outdoor power circuit board.