High Pressure Error (Ball Valve Closed)

What does UE mean?

The system is experiencing high refrigerant pressure, specifically indicating that a ball valve, most likely a service valve in the refrigerant circuit, is closed or partially closed, restricting refrigerant flow.

1. 1

   Inspect all service ball valves (liquid line, suction line) on the outdoor unit — verify they are fully open.

2. 2

   Measure high-side pressure using manifold gauges after confirming all valves are open.

3. 3

   Check for any other flow restrictions in the liquid line such as a clogged filter drier.