BoilerFaultCodesTechnical description
Feedback from the modulating gas valve is too low
What causes this fault?
This fault occurs when the boiler's main computer loses the precise electrical signal it needs to manage the gas flow safely. The most common reason is an internal electronic failure within the gas valve itself or a loose connection in the wiring that links the valve to the control board. Without this constant 'heartbeat' feedback, the boiler shuts down as a safety precaution because it cannot verify exactly how much fuel is being used.
Engineer required
This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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