P6 Error Code – Low Pressure Protection

The P6 error appears when the system’s refrigerant pressure drops below a safe operating level. This typically indicates the system is low on refrigerant, which may be due to a leak.

What Causes This?

Low system pressure prevents the unit from operating correctly. In most cases, this is caused by a refrigerant leaksomewhere in the system.

Quick Test You Can Try

1. Set the unit to maximum heating temperature.

2. Let it run for 15 minutes.

3. Check the larger pipe coming out of the outdoor unit:

   • It should be very hot (around 105°F) — almost too hot to touch.

   • If it’s not hot, the system is likely low on refrigerant.

Normal Pressure Readings (for reference)

• Heating Mode: Approximately 400 psi

• Cooling Mode: Approximately 100 psi

Additional Resources

For a more detailed diagnosis and specific tests, refer to the documents below:

• [P6 Error Code PDF] – In-depth troubleshooting steps

• [E3/F5 Error Code PDF] – Related codes and procedures