BoilerFaultCodesYour boiler is currently trying to light the flame to start provide heating or hot water, and this is a normal status message rather than a permanent error.
This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.
Technical description: Ignition sequence
What causes this fault?
This code appears when the boiler's control system sends a signal to generate a spark and open the gas valve simultaneously. It is a natural part of the start-up process where the appliance attempts to establish a flame to satisfy a demand for heat. If the boiler stays on this code without firing, it usually means there is a temporary struggle to sense the flame or a delay in gas reaching the burner.
DIY fix possible
Check that your gas supply is turned on at the meterEnsure your wireless thermostat has fresh batteriesWait up to 10 minutes to see if the boiler moves past this status into a heating cycle
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like S.3 — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.