BoilerFaultCodesYour boiler has detected that there is not enough water pressure or water is not moving through the system properly to operate safely.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: No Water Flow
What causes this fault?
This fault occurs when the boiler's internal sensors detect that water isn't moving through the unit, which risks the heat exchanger overheating. The most common reasons are a seized internal pump, a build-up of sludge blocking the pipes, or a faulty pressure sensor that is incorrectly reporting a lack of water.
This issue is frequently seen at the start of autumn when heating systems are turned back on after sitting idle all summer, which can cause the pump to seize.
DIY fix possible
Check the pressure gauge on the front of the boiler; it should be between 1 and 1.5 bar.If the pressure is low, use the filling loop handles underneath the boiler to top it up until the needle reaches the green zone.Ensure all radiator valves and isolation valves under the boiler are fully open.Reset the boiler by turning the control knob to 'RE' or pressing the reset button.
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A boiler cover plan would cover faults like 4.4 — no call-out fees, no surprises.
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Could it be time for a new boiler?
If repair costs are adding up, a new energy-efficient boiler could be the smarter long-term choice.
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