BoilerFaultCodesWhat the manual says
Manufacturer manualHot water demand (hot water operation)
What causes this fault?
This status appears when the boiler detects a flow of water through the internal heat exchanger, signaling a request for hot water. It confirms that the sensors have successfully identified that a tap or shower is turned on and the burner is firing to heat that water. Since this is an operational message rather than a breakdown, it simply means the system is doing exactly what it was designed to do.
DIY fix possible
Check if any hot water taps are currently turned onEnsure there are no leaking or dripping hot water taps in the propertyIf the code remains when all taps are off, check your pre-heat settings or potential internal leaks
Avoid the next call-out bill
A cover plan would handle faults like S.10: no call-out fees, no surprise bills.
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