BoilerFaultCodesWhat the manual says
Manufacturer manualsummer mode
What causes this fault?
This code appears when the boiler has been manually set to Summer Mode, which instructs the unit to prioritize hot water but ignore requests for heating. It occurs because the central heating temperature control has been turned fully off or a specific seasonal setting has been activated on the interface. It is a status indicator rather than a mechanical failure, meaning the boiler is working exactly as it has been instructed.
This code is most common during late spring and summer when homeowners intentionally turn off their heating to save energy.
DIY fix possible
Locate the central heating temperature control knob on the boiler fascia.Turn the dial clockwise to increase the heating temperature setting.The code should disappear once a temperature is set and a heat demand is made.
Avoid the next call-out bill
A cover plan would handle faults like S.31: no call-out fees, no surprise bills.
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