BoilerFaultCodesTechnical description
Return sensor fault
What causes this fault?
This fault occurs when the internal control board receives an incorrect or missing electrical signal from the sensor that monitors water returning from your radiators. The most common reason is that the sensor has physically failed or 'drifted' out of its correct range, but it can also be caused by loose wiring or moisture damaging the sensor's connection.
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.
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