BoilerFaultCodesTechnical description
Flow or return sensor fault. Short circuit in the flow, return or boiler temperature sensor. Defective or not (properly) connected flow, return or boiler temperature sensor.
What causes this fault?
This fault occurs when the boiler's control board receives an impossible electrical signal from the sensors that monitor water temperature. It is usually caused by a sensor internal component failing due to age or a loose connection in the wiring that prevents the boiler from knowing if the operation is safe. The system shuts down instantly to prevent the unit from 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 →