BoilerFaultCodesTechnical description
Ignition failure/not flame sensed, condense sensor activated
What causes this fault?
This fault occurs when the boiler tries to ignite but fails to establish a steady flame, or if the safety sensors detect that the waste water cannot drain away properly. The most common reason is a blockage in the condensate trap or external pipework, which causes water to back up into the heat exchanger and extinguish the burner. It can also be triggered by worn ignition components that can no longer create a strong enough spark to light the gas.
This fault is frequently seen during freezing winter spells, as the external condensate pipe can freeze solid and cause the boiler to shut down for safety.
Engineer required
This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.