E40 - High-pressure switch (B3H or 63H1) tripped, or airflow issue

What does E40 mean?

The high-pressure switch (B3H or 63H1) has tripped, indicating abnormally high pressure in the refrigerant system. This could be due to an overcharge, closed service valves, or insufficient airflow over the condenser coil.

• High-pressure switch (B3H or 63H1) activation.
• System overcharged with refrigerant.
• One or more service valves are shut.
• Insufficient airflow over the condenser coil (e.g., due to blockages).

Click steps to track your progress.

1. 1

   Turn off the air conditioning unit and allow it to cool down for at least one hour.

2. 2

   Inspect the outdoor unit's condenser coils and fan for any blockages or debris. Clear if found.

3. 3

   Ensure all service valves (if safely accessible and user-serviceable) are fully open.

4. 4

   If the error persists, contact a certified HVAC technician to check refrigerant levels and system pressures.