BoilerFaultCodesYour boiler is currently working to heat your hot water tank and this status code is just a normal operational message rather than a fault.
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: domestic hot water demand
What causes this fault?
This status occurs when the external cylinder thermostat or the boiler's internal controls detect that your hot water tank has cooled down and needs reheating. The boiler physically switches its internal valves to direct heat toward the water cylinder rather than your radiators to ensure you have a full supply of hot water for taps and showers.
DIY fix possible
Check if your hot water timer or thermostat is currently calling for heatWait for the boiler to finish heating the cylinder to see if the code changes to a standby modeNo action is required as this is a normal status indicator
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A boiler cover plan would cover faults like S.10 — no call-out fees, no surprises.
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