BoilerFaultCodesWhat the manual says
Manufacturer manualService Mode / Sequence indicator following the last 3 faults
What causes this fault?
This code appears when the boiler has been manually put into a specialized mode for testing or when the system is displaying a history of its most recent operations. It is physically triggered by an engineer interacting with the control buttons to check how the boiler is firing or to diagnose previous issues. Because this is a manual override state rather than a mechanical failure, it does not indicate that any internal parts have broken.
DIY fix possible
Check if the function knob is set to 'Reset' or a specific service position.Turn the selector knob back to the 'on' or 'standby' position.Press the reset button briefly to return the boiler to normal operation mode.
Avoid the next call-out bill
A cover plan would handle faults like SL: no call-out fees, no surprise bills.
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