BoilerFaultCodesTechnical description
Burner failed to light. Check gas supply and gas valve operation. Check fan and spark operation. Check flue for blockage. Clean or replace ionisation probe & lead. Check condensate outlet not blocked & vent tube is clear
What causes this fault?
This fault occurs when the boiler's control system attempts to start the burner but fails to detect a stable flame after several attempts. The most common reasons include a lack of gas reaching the unit, a dirty or worn-out sensor that can't 'see' the flame, or a build-up of debris in the internal components that prevents a successful spark.
This fault is frequently seen during the first cold snap of winter when a blocked condensate pipe can freeze, causing water to back up and prevent the boiler from lighting.
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.