BoilerFaultCodesTechnical description
Flow sensor error
What causes this fault?
This fault occurs when the boiler's internal thermometer, which measures the water temperature as it leaves the unit, sends an incorrect or missing signal to the control board. The most common reason is that the sensor has physically failed due to age or wear, though loose or damaged electrical wiring can also prevent the sensor from communicating correctly.
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 →