BoilerFaultCodesTechnical description
Flow and return sensor anomaly detected. Sudden temperature change detected on the flow or return sensor.
What causes this fault?
This fault occurs when the boiler's internal sensors detect an impossibly fast rise or fall in temperature, suggesting that water isn't moving through the unit correctly. The most common reason is a circulation failure, often caused by a faulty pump or a blockage in the pipework that prevents heat from being carried away from the heat exchanger.
This issue is more frequent when the heating is first turned on after summer, as pump components can seize up during long periods of inactivity.
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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