High-Pressure Switch Tripped / System Overcharge / Service Valves Closed / Insufficient Airflow

What does E40 mean?

The high-pressure switch (B3H or 63H1) has tripped. This can be caused by a system overcharged with refrigerant, one or more service valves being shut, or insufficient airflow over the condenser coil, all leading to dangerously high system pressures.

• High-pressure switch (e.g., PS2) has tripped.
• System is overcharged with refrigerant.
• Service valves are closed, restricting refrigerant flow.
• Insufficient airflow across the outdoor unit heat exchanger.
• Outdoor fan motor failure.

Click steps to track your progress.

1. 1

   Check the state of the high-pressure switch (B3H or 63H1) for tripped condition and manually reset if permissible.

2. 2

   Verify the refrigerant charge using a manifold gauge set; if overcharged, recover refrigerant to specification.

3. 3

   Ensure all liquid line and suction line service valves are fully open.

4. 4

   Inspect the condenser coil for obstructions and verify the outdoor fan operation to ensure sufficient airflow.