BoilerFaultCodesTechnical description
The low system pressure neon is illuminated, indicating the system pressure is too low.
What causes this fault?
This fault occurs when the water levels inside your radiators and pipework drop below a functional level, meaning the boiler can no longer circulate heat safely. The most common reason is a tiny leak somewhere in the system or because the air was recently bled out of your radiators without topping the water back up. In some cases, a failing internal component like the expansion vessel may be causing the pressure to fluctuate and escape.
This issue often surfaces when you turn your heating back on for the first time in autumn, as the system settles after being dormant all 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.