F28 Start-up failure — Ignition unsuccessful

What does F28 mean?

The boiler failed to ignite. This can be due to a lack of gas, low gas pressure, blockages, or issues with the ignition system components like the transformer, cable, or electrode.

• Gas meter defective or gas pressure monitor triggered
• Air in gas
• Gas flow pressure too low
• Condensate duct blocked
• Fault on the gas valve
• Ignition system (transformer, cable, plug, electrode) defective
• Incorrect earthing of product
• Electronics defective

Click steps to track your progress.

1. 1

   Check if the gas valve is opening by observing manometer drops during ignition (requires specialist tools).

2. 2

   Ensure the boiler is sparking and the flue is clear of obstructions.

3. 3

   If it ignites and then faults to F28, check continuity down the electrode and the earth wire (requires specialist tools).

4. 4

   Perform a strip service: clean the burner, clear the flue run, and check inlet standing and working pressures (requires specialist tools).

5. 5

   Check ignition electrodes for damage or incorrect positioning.