BoilerFaultCodesTechnical description
Return temperature sensor error (S2)
What causes this fault?
This fault occurs when the boiler's internal computer loses communication with the sensor that monitors water coming back from your radiators. The most common reason is that the sensor has physically failed or developed a chemical build-up, but it can also be caused by loose electrical connections or a fault on the main control board.
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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