Lennox heat_pump Error Code E228

High Pressure Switch Open

What does E228 mean?

High side refrigerant pressure exceeded safe operating limit.

Common causes

Diagnostic & testing steps

  1. 1. Check discharge pressure: normal 375-400 PSI R-410A at 95°F
  2. 2. Clean condenser coil with coil cleaner and rinse
  3. 3. Verify condenser fan is running and correct direction
  4. 4. Test condenser fan capacitor
  5. 5. Check subcooling: overcharged if >15°F

Tools required

OEM parts & part numbers

Condenser Fan Motor, Fan Capacitor

Part numbers: 25M48, 89W59

Safety warning

⚠️ Do not open any refrigerant circuit fittings while system is under high pressure.

Try DiagBuddy AI free — instant 30-second diagnostics for technicians.