BoilerFaultCodesYour boiler has lost its ability to accurately measure the temperature of the water coming back from your radiators, which may stop your heating from working efficiently or at all.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Return sensor defective (zone 1)
What causes this fault?
This fault occurs when the internal computer can no longer read a consistent or accurate signal from the sensor that monitors water returning from your radiators. The most common reason is that the sensor's internal electrical resistance has failed, but it can also be caused by loose or corroded wiring connections inside the boiler.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Could it be time for a new boiler?
If repair costs are adding up, a new energy-efficient boiler could be the smarter long-term choice.
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