BoilerFaultCodesYour boiler is overheating too quickly because water isn't moving through the system fast enough.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Flow temperature rise in heat exchanger too rapid
What causes this fault?
This fault occurs when the water inside the boiler heats up much faster than the system can carry it away, causing the unit to shut down to prevent damage. The most common reasons are a failing internal pump that isn't pushing the water through, or a build-up of sludge and debris that has restricted the narrow channels within the heat exchanger.
This issue often comes to light during the first cold spell of autumn when the heating is turned back on after being idle all summer, which can cause internal pump components to seize.
DIY fix possible
Check that all radiator valves are fully openEnsure the system pressure is between 1.0 and 1.5 barBleed your radiators to remove any trapped air
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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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