BoilerFaultCodesWhat the manual says
Manufacturer manualHeating return sensor fault
From this model's manual
Verified against the Alpha E Tec Regular installation & service manual, page 46.
What causes this fault?
This fault occurs when the boiler's control board receives an incorrect or missing signal from the sensor that measures the temperature of the water coming back from your radiators. The most common reason is that the internal components of the sensor have failed due to age, or the electrical wiring connecting the sensor to the main computer has become loose or damaged.
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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