BoilerFaultCodesTechnical description
If the red arrow on the system pressure gauge is set above zero and the system pressure is seen to fall below this value over a period of time then a water leak is indicated. DO NOT FIRE THE BOILER IF THE PRESSURE HAS REDUCED TO ZERO FROM THE ORIGINAL SETTING.
What causes this fault?
This fault occurs when water escapes from the sealed pipework, causing the internal pressure to drop below the level needed for the boiler to pump heat around your home. The most common reasons are a slow leak from a radiator valve, a perished seal inside the boiler, or a failing expansion vessel that can no longer regulate system pressure.
This issue is frequently noticed in autumn when the heating is turned on for the first time after summer, as the change in temperature and pressure can expose weakened seals or small weep leaks.
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.