BoilerFaultCodesYour boiler has detected that there is not enough water pressure or flow to operate safely and has shut down to prevent overheating.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Dry fire protection | No water in appliance, pump cable defective, pump blocked or defective, pump output too low
What causes this fault?
This fault occurs when the boiler detects a critical lack of water or a failure in the circulation system, preventing it from moving heat away from the burner. The most common reason is a significant drop in system pressure, but it can also be triggered if the pump has seized or failed to start. Without sufficient water flow, the internal sensors shut the system down immediately to prevent the heat exchanger from melting or cracking.
This fault is frequently seen in autumn when heating systems are turned back on after being idle all summer, which can cause the internal pump to seize.
DIY fix possible
Check the pressure gauge on the front of the boiler; it should be between 1.0 and 1.5 bar.If the pressure is too low, use the external filling loop valves to top up the system with water.Attempt to reset the boiler once the correct pressure is reached.
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A boiler cover plan would cover faults like F.22 — no call-out fees, no surprises.
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