BoilerFaultCodesYour boiler has detected that either the water pressure is too low for the system to run or the internal pump is unable to circulate water effectively.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Fault on Pump or Low System Pressure
What causes this fault?
This fault occurs when there isn't enough water pressure or flow to safely move heat away from the boiler's internal components. The most common reasons are a simple drop in system pressure due to a small leak or bleeding radiators, or a mechanical failure where the internal pump has seized and can no longer push water around your home.
This issue is frequently seen in autumn when heating systems are turned back on after being idle all summer, which can cause the internal pump to stick or 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 below 1 bar, use the filling loop underneath the boiler to top up the system.Turn the boiler off and back on again to reset the fault code.
Find a Gas Safe engineer
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A boiler cover plan would cover faults like 27 — 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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