Too Low Superheat Due to Low Discharge Temperature

What does U7 mean?

The system continuously detects discharge superheat less than or equal to -15°C [5°F] for 3 minutes, even with the linear expansion valve (LEV) at its minimum open pulse and the compressor running for 10 minutes. This indicates potential liquid floodback to the compressor, posing a significant risk of compressor damage.

Additional Steps

Steps 1–2 are listed in Priority Fix.

1. 3

   Check the coil of the linear expansion valve for disconnection or loose connections.

2. 4

   Check the connection and contact of the LEV-A and LEV-B connectors on the outdoor controller circuit board.

3. 5

   Check the linear expansion valve for proper operation, referring to section 10-6 for diagnostic procedures.