BoilerFaultCodesTechnical description
Pressure reading below 0.5 bar on the gauge
What causes this fault?
This fault occurs when the internal water pressure drops below the minimum level required for the boiler to operate safely. The most common reason is a slow leak from a radiator valve or a pipe joint, but it can also happen if you have recently bled your radiators and didn't top up the system afterwards. In some cases, a component inside the boiler like the pressure relief valve may be letting water out of the system gradually.
This fault is frequently seen at the start of autumn when homeowners turn their heating back on for the first time after the summer break.
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.