BoilerFaultCodesTechnical description
Water pressure too low – the water needs topping up and the vent system or pressure sensor may need replacing
What causes this fault?
This fault occurs when the system loses too much water, preventing the boiler from circulating heat safely. The most common reasons are a slow leak from a radiator valve or the natural loss of pressure that happens after you bleed your radiators. If the pressure looks normal on the gauge but the code persists, the internal sensor that reads the water level may be blocked or broken.
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 in the system.
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.