Compressor Overcurrent Interruption (Locked)

What does UF (100) mean?

An overcurrent condition on the DC bus or compressor is detected within 30 seconds after the compressor starts operating. This indicates a locked compressor state. Common causes include a closed stop valve, decreased power supply voltage, loose, disconnected, or reversed compressor wiring connection, a defective compressor, or a faulty outdoor power board.

• Compressor is drawing excessive current, potentially locked or overloaded (UF code).
• Mechanical binding or seized compressor rotor.
• High differential pressure across the compressor.
• Over-temperature condition within the compressor windings.

Click steps to track your progress.

1. 1

   Open the stop valve.

2. 2

   Check the facility of the power supply.

3. 3

   Correct the U·V·W phase wiring to the compressor. Refer to section 10-9 (Outdoor power circuit board).

4. 4

   Check the compressor. Refer to section 10-6.

5. 5

   Replace the outdoor power circuit board.