BoilerFaultCodesYour boiler is currently going through its routine process of lighting the flame to start heating your water.
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 status code appears when the boiler is actively trying to light the gas burner to provide heating or hot water. It represents a normal part of the startup cycle where the internal computer checks the safety sensors before opening the gas valve and creating a spark. If this code stays on screen for a long time without the boiler firing up, it usually suggests a delay in the ignition process.
DIY fix possible
No action required; this is a normal status message and not a fault.Wait for the boiler to complete the ignition sequence.Ensure your thermostat is calling for heat or hot water.
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A boiler cover plan would cover faults like S.03 — no call-out fees, no surprises.
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