BoilerFaultCodesYour boiler has detected a problem with the flow of water while trying to heat your taps, which usually means water isn't moving through the system correctly.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Hot water handling pump flow error
What causes this fault?
This fault occurs when the boiler's internal sensors detect that water isn't moving quickly enough through the system to safely transfer heat to your hot water. The most common reason is a blockage caused by limescale or debris in the heat exchanger, or a mechanical failure in the secondary pump that pushes the water around.
DIY fix possible
Check that all service valves under the boiler are fully openEnsure your radiators are bled and there is no trapped air in the systemVerify that the system pressure is between 1.0 and 1.5 bar on the display
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like S.22 — no call-out fees, no surprises.
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Vaillant ecoTEC 65kW is discontinued — time for a new one?
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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