BoilerFaultCodesTechnical description
No flame or no ionisation (after 3 starts): a. no ignition spark (visible through inspection glass). Check: connection of ignition cable and spark plug cap; ignition cable and electrode for breakdown; electrode distance; must be 3-4 mm. b. ignition spark, but no flame. Check if: gas cock is open; inlet gas pressure is sufficient; gas pipe is vented; gas valve is energized during ignition; electrode is fitted properly; the gas/air ratio is not correct; the gas pipe is not clogged or shows an assembly fault. c. flame, but no ionisation.
What causes this fault?
This fault happens because the boiler has attempted to light three times but failed to establish or detect a steady flame. It is usually caused by a worn-out ignition spark or a problem with the gas supply reaching the burner. Without a confirmed flame, the boiler shuts down as a safety measure to prevent unburned gas from accumulating inside the unit.
This issue is more frequent during the first cold snap of autumn when internal components that have been idle over summer fail to operate correctly upon restart.
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.