Boiler shows F.29 after starting then going out, intermittent hot water or heating

Safety: Flame loss can indicate combustion issues. Do not ignore repeated F.29 faults.

• Check other gas appliances: If they also cut out, contact your gas supplier.
• Visual flue check: Ensure the flue terminal is clear of obstructions outside.
• Reset and observe: Reset the boiler and watch the flame through the viewing window (if present). If the flame lights then goes out repeatedly, stop using the boiler and call an engineer.
• Engineer checks: A technician will verify gas pressure, clean or replace the ionisation electrode, check fan speed and air intake, and confirm combustion with a flue gas analyser.