BoilerFaultCodesTechnical description
If the pressure falls below 0.5, this may indicate a leak on the central heating system.
What causes this fault?
This fault occurs when the sealed water circuit inside your heating system loses enough water to drop below the safe operating limit. The most common reasons are tiny leaks from radiator valves or the automatic air vent, as well as air being released from the system through the radiators. Without enough water pressure, the boiler cannot safely circulate heat and shuts down to prevent internal damage.
This issue is frequently seen in autumn when the heating is turned back on for the first time, as the change in temperature can cause joints to weep or trapped air to move through the pipes.
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.