F.28 — Failure during start-up: Ignition unsuccessful

What does F.28 mean?

The boiler failed to ignite successfully during its start-up sequence. This means it couldn't establish a flame to begin heating.

• Gas meter is defective or the gas pressure regulator has triggered a safety shut-off.
• Air present in the gas supply line.
• Gas flow pressure is too low.
• Condensate duct is blocked, preventing proper flue gas exhaust.
• Faulty earthing of the boiler, or a defective ignition system (transformer, cable, plug, electrode).

Click steps to track your progress.

1. 1

   Check that your gas supply to the property is active and other gas appliances are working.

2. 2

   Inspect the condensate pipe, usually a plastic pipe outside, to ensure it's not frozen or blocked.

3. 3

   Press the fault clearance key on the boiler to reset it. If the fault persists, contact Vaillant Service Solutions.