F33 Fault — Fan frost protection active / Air pressure switch fault

What does F33 mean?

The fan frost protection function is active, indicating an air pressure switch fault. This could be due to the pressure monitor not switching, insufficient air supply, or issues with the pressure monitor connections or air/flue pipes.

• Air pressure switch fault
• Pressure monitor has not switched or has switched at a fan speed value that is too high (insufficient air supply)
• Pressure monitor plug not correctly plugged in
• Pressure monitor defective
• Line removed from between the pressure monitor and silencer
• Air/flue pipe blocked
• Silencer not installed properly

Click steps to track your progress.

1. 1

   Check that the pressure monitor plug is correctly plugged in.

2. 2

   Inspect the line between the pressure monitor and silencer to ensure it's in place.

3. 3

   Check the air/flue pipe for any blockages or restrictions.

4. 4

   Verify that the silencer is installed properly.

5. 5

   If issues persist, the pressure monitor itself may be defective (contact a technician).