Compressor Overcurrent (Overload) Cut-off

What does U6 mean?

The compressor has experienced an overcurrent condition due to an overload, leading to a safety cut-off. This could be caused by mechanical issues, excessively high head pressure, or an electrical fault within the compressor motor or associated circuit.

1. 1

   Measure compressor running current on all three phases using a clamp meter — compare measured values to the motor nameplate FLA.

2. 2

   Measure discharge and suction pressures to rule out high head pressure or liquid slugging as a cause.

3. 3

   Measure winding resistance of the compressor motor phases (U-V, V-W, U-W) and to ground using an ohmmeter — expect balanced resistance and no ground fault.