F.77 — Condensate pump or accessory feedback blocks heating

What does F.77 mean?

The condensate pump or feedback from another accessory is blocking the boiler's heating operation. This could mean the condensate pump is defective or a flue flap feedback mechanism has been triggered.

• Condensate pump defective.
• Flue flap feedback triggered.
• Blockage in condensate system.

Click steps to track your progress.

1. 1

   Check the condensate drain for any blockages or kinks in the pipework.

2. 2

   Ensure the condensate pump (if fitted) is operating correctly and not overflowing.

3. 3

   If the error persists, contact a qualified service technician to inspect the condensate pump and accessory feedback system.