Boiler shows F29 after starting then shutting down, flame goes out during operation

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

Possible Causes

Unstable gas supply, Blocked burner or injector, Faulty ionisation electrode, Condensate backing up into combustion chamber

Safety first: Turn off power and gas before opening the boiler casing.

Steps to check:

Check that the condensate trap and pipe are not blocked or frozen.
Inspect the burner for signs of corrosion or debris; cleaning is an engineer task.
Check the ionisation electrode and cable for secure connection and cleanliness.
Reset the boiler. If F29 recurs, a professional must check gas pressures and combustion quality.

Warning: Flame loss can indicate serious combustion issues. Do not ignore repeated F29 faults.

Hard 4/5

Ionisation Electrode / Burner

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