BoilerFaultCodesYour boiler is simply going through its normal process of lighting the burner to provide you with hot 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: DHW mode: Ignition. The ignition for domestic hot water mode is activated.
What causes this fault?
This is a normal status code rather than a fault, occurring every time you turn on a hot tap. It indicates that the boiler's internal computer has successfully detected a request for hot water and is now physically sparking the burner to heat it. Once the flame is established and the water reaches the set temperature, this code will typically transition to another status.
DIY fix possible
This fault may be fixable without an engineer. Check your manual first.
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A boiler cover plan would cover faults like S.23 — no call-out fees, no surprises.
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