BoilerFaultCodesTechnical description
Pressure less than 1 bar or pump pressure increase too low (no pump detection).
What causes this fault?
This fault occurs when the boiler's internal sensors detect that the system lacks the minimum water pressure required to circulate heat safely. The most common reason is a slow leak somewhere in the pipework or radiators, but it can also be triggered if the pump has failed and can no longer push water through the heat exchanger.
This code is frequently seen in autumn when the heating is turned on for the first time after summer, as dormant seals may have weeped or air has become trapped in the radiators.
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.
Find a Gas Safe engineer
Search the official register →