Compressor overcurrent interruption (Locked rotor)

What does UF mean?

Compressor overcurrent is detected within 30 seconds of starting, indicating a locked rotor condition. This can be caused by a closed stop valve, low power supply voltage, incorrect compressor wiring, or a defective compressor or outdoor power board. This fault causes an immediate shutdown to prevent damage, but recurring issues can severely shorten compressor lifespan.

1. 1

   Verify that all stop valves are fully open.

2. 2

   Check the power supply facility for adequate and stable voltage.

3. 3

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

4. 4

   Test the compressor for proper operation and resistance values. Refer to Section 10-6.

5. 5

   Replace the outdoor power circuit board if all other components are verified to be functioning correctly.