BoilerFaultCodesWhat the manual says
Manufacturer manualDHW demand. The domestic hot water demand is activated.
What causes this fault?
This code appears when the boiler recognizes that a hot water tap or shower has been opened somewhere in your home. It occurs because a flow sensor has detected moving water and has signaled the internal components to begin the heating process. It is a normal part of the boiler's operation and simply confirms that the system is responding correctly to your request for hot water.
DIY fix possible
No action is required as this is a normal status message, not a fault.If the code stays on when all taps are off, check for dripping taps or leaks.If the code appears but no hot water comes out, contact a Gas Safe engineer.
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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