Technical description
Pressure sensor defective or not connected – check pressure sensor connection as it may need replacing
What causes this fault?
This fault occurs when the boiler's brain loses contact with the sensor that monitors water pressure, often due to a loose wire or a physical failure inside the sensor itself. Without this vital data, the boiler shuts down as a safety precaution because it cannot confirm there is enough water to operate without overheating.
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 →