Error F.29

Safety first:

1) If you smell gas, leave the property immediately, do not operate electrical switches or the boiler, open windows, and call the gas emergency number from a safe location. 2) If the boiler has locked out and there are no signs of gas smell, you can carry out basic safe checks below. Do NOT try to access internal burner parts, change gas valves, or carry out electrical repairs yourself. Call a Gas Safe engineer for any work on gas or sealed components.

Initial checks a homeowner can do:

1) Note any other symptoms: gurgling noises from the boiler, whether the fault appears only in cold weather, whether other gas appliances are working, and whether you recently had freezing weather. 2) Check the gas supply at the meter: ensure the meter is not off and that any prepayment key has credit. If other gas appliances are not working, contact your gas supplier. 3) Try a boiler reset: locate the reset button on your Vaillant control panel and hold for about 5 seconds (follow your boiler manual). If the fault clears and the boiler runs normally, monitor for recurrence.

Check the condensate pipe (common winter cause):

1) Locate the condensate discharge pipe (typically white plastic running to outside drain). If it is frozen or visibly blocked, thaw it by pouring warm (not boiling) water over the frozen section, or use a warm cloth. Do not use open flames or sharp tools. 2) Once thawed, attempt a reset. If the boiler runs, insulate the pipe or fit a heat-trace/lagging to prevent refreeze and arrange service if needed.

Other homeowner checks you can safely do:

1) Look at the flue external terminal for obvious obstructions (nests, leaves, debris). Do not dismantle the flue or force anything into it. If you see a blockage, report this to an engineer. 2) Check the boiler display and note the exact error history and any accompanying codes or LEDs — this information is useful to the engineer.

When to call a Gas Safe engineer (and what they will check):

1) Call a Gas Safe registered engineer if the fault persists after basic checks and resetting, or if you are unsure. Give them the F.29 code, describe recent conditions (freezing weather, loss of gas supply, gurgling, smell of gas), and say whether a reset helped temporarily. 2) The engineer will safely test gas pressure and the gas valve, inspect and if necessary clean or replace the ignition electrode and leads, check and clean the burner, inspect the flue and condensate drainage, test the PCB and safety controls, and repair any internal leaks that may have damaged ignition components. They have the correct tools, spares and gas-safety certification.

Do not attempt:

1) Replacing or adjusting gas valves, servicing the burner, handling ignition electrodes or wiring, or changing the PCB yourself — these are gas/electrical safety tasks that require a Gas Safe engineer. 2) Using the boiler repeatedly if it repeatedly locks out — arrange a diagnosis rather than repeated resets.

If your boiler is under service or warranty, or you have an emergency cover plan, contact the relevant service line and provide the F.29 code and your boiler model. If you are unsure who to call, find a Gas Safe registered engineer through the official Gas Safe register.