BoilerFaultCodesYour boiler has built up too much internal water pressure and is releasing it through a safety valve to prevent damage.
Turn off your boiler and stop using gas appliances. Call a Gas Safe engineer now — this fault can be dangerous if ignored.
Technical description: Safety valve is prompted to relieve excess pressure from the primary circuit
What causes this fault?
This fault occurs when the water pressure inside your heating system rises above safe levels, often because the expansion vessel has lost its air charge or failed. The boiler triggers this code as it uses a safety valve to eject water and protect internal components from being crushed by the high pressure. It can also happen if the filling loop was left slightly open, causing the system to overfill unintentionally.
This fault is more common in winter when homeowners turn their heating on for the first time, as the rapid heating of water puts the most strain on the expansion vessel.
DIY fix possible
Check if the filling loop valves are fully closed and not leaking water into the systemBleed a small amount of water from a radiator using a bleed key to reduce the pressure gauge reading to 1.5 barReset the boiler using the control knob
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