BoilerFaultCodesYour boiler is temporarily running at a lower power than usual to protect itself from overheating or to manage heat demand.
This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.
Technical description: Forced part load.
What causes this fault?
This code appears when the boiler detects that it is getting too hot too quickly, often because of a restriction in water flow through the heat exchanger. The boiler automatically lowers its power output to keep running safely without shutting down completely. The most common reasons are a build-up of sludge in the system, a pump that is starting to fail, or air trapped within the pipework.
This code is often seen at the start of autumn when the heating is turned back on after a long break, as internal pump components can become stiff or stuck.
DIY fix possible
Check that all radiator valves are fully open to allow water to circulateEnsure the system water pressure is between 1.0 and 1.5 bar on the gaugeWait for the boiler to complete its cycle, as this is often a normal operational state
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