BoilerFaultCodesYour boiler has experienced an internal electrical short circuit which has likely blown a protective fuse, causing it to stop working entirely.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Short-circuiting in the 24 V circuit (three-way valve or connector); check for a short-circuit and replace the F3 fuse in the control panel.
What causes this fault?
This fault occurs when an internal electrical component, usually the motor that moves between heating and hot water, develops a fault and draws too much power. This surge causes a protective fuse on the main control board to blow, which cuts power to the boiler to prevent further damage. The most common root cause is water or moisture entering the three-way valve motor, causing it to short out.
This issue often surfaces in autumn when the heating is turned on for the first time after summer, as the three-way valve may have seized from lack of use.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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