Error 428 — Compressor operation stop due abnormal compression ratio

What does 428 mean?

The compressor has stopped operating because the system detected an abnormal compression ratio. This indicates an issue with how the compressor is processing refrigerant, which can lead to system damage.

• Refrigerant overcharge or undercharge
• Blockage in the refrigerant circuit (e.g., expansion valve, filter dryer)
• Compressor malfunction
• Faulty pressure sensors providing incorrect readings

Click steps to track your progress.

1. 1

   Turn off the outdoor unit and wait for a few minutes for the system pressures to equalize.

2. 2

   Perform a power cycle by turning off the unit's circuit breaker for 30 seconds, then restoring power.

3. 3

   Check for any obvious signs of refrigerant leaks (frost, oil residue) around the outdoor unit.

4. 4

   This error requires specialized tools and expertise to diagnose the exact cause of the abnormal compression ratio.

5. 5

   Contact a certified HVAC technician for professional diagnosis and repair.