BoilerFaultCodesTechnical description
The appliance is blocked because of a water deficiency.
What causes this fault?
This fault occurs when the system loses too much water, causing the internal pressure to drop below a safe operating level. The most common reasons are a slow leak somewhere in your radiators or pipework, or a component like the pressure relief valve failing and letting water escape. Without enough water pressure, the boiler cannot circulate heat safely and shuts down to prevent the internal components from overheating.
This fault is frequently seen in autumn when homeowners turn their heating back on for the first time, as the change in temperature can highlight small leaks or air pockets that developed over the summer.
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.