BoilerFaultCodesYour boiler is temporarily running at a lower power than normal to protect its internal parts from overheating or poor water circulation.
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 heat isn't moving away from the internal heat exchanger quickly enough, often due to a buildup of sludge or a failing pump. To prevent internal damage from overheating, the boiler automatically 'throttles back' and limits its power output until the temperature stabilizes. It is essentially the boiler’s way of protecting itself while still trying to provide you with some heat.
This is more common when you first turn the heating on in autumn, as debris settled over the summer can move into the pump and restrict water flow.
DIY fix possible
Check that all radiator valves are fully openEnsure the boiler pressure is between 1.0 and 1.5 barCheck for any obstructions in the flue or air vents
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