BoilerFaultCodesYour boiler has detected that water is not circulating correctly, often because there is trapped air or the system pressure is too low.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Return temperature is higher than the flow temperature. Insufficient water. No through flow. Too much air in the system. Sensors not wired correctly. Deviation in the flow or return temperature sensor.
What causes this fault?
This fault occurs when the boiler's internal sensors detect that the temperatures are the wrong way around or not changing as expected, suggesting water isn't moving through the unit. The most common reasons are a lack of water pressure, a buildup of trapped air pockets, or a pump that has seized and can no longer push water around your radiators. Essentially, the boiler is shutting down to prevent itself from overheating because the heat it produces has nowhere to go.
This issue often appears in autumn when the heating is turned on for the first time after summer, as pump components can seize during long periods of inactivity.
DIY fix possible
Check the pressure gauge and top up to 1.5 bar if it is lowBleed all radiators to remove trapped airEnsure all radiator valves and isolation valves are fully openReset the boiler using the reset button
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A boiler cover plan would cover faults like é2 — no call-out fees, no surprises.
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Parts for discontinued models can be hard to find and expensive. A new A-rated boiler could save you money on both repairs and energy bills.
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