BoilerFaultCodesYour boiler has temporarily paused its operation because it senses there is not enough water flowing through the system to heat your home safely.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Delay mode due to lack of water in system (~20 mins.)
What causes this fault?
This fault occurs when the boiler's internal sensors detect that the water is heating up far too quickly or isn't moving through the unit fast enough. The most common reasons are a build-up of sludge blocking the heat exchanger, a pump that is failing to circulate the water, or simply air trapped within the system. To prevent internal damage from overheating, the boiler enters a temporary waiting period to allow the components to cool down.
This issue is most frequent in autumn when the heating is turned back on after a long summer break, as stagnant debris in the pipes can settle and cause blockages.
DIY fix possible
Check the pressure gauge on the front of the boilerIf the pressure is below 1 bar, use the filling loop valves to top the system up to 1.5 barCheck all radiators for leaks and bleed them if necessary to remove trapped airOnce pressure is restored, the boiler should restart automatically after the 20-minute delay
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