BoilerFaultCodesYour boiler has sensed that the temperature is rising too quickly inside the unit, often caused by water not flowing through the pipes 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: Activation of maximum ELTA T protection
What causes this fault?
This fault occurs when the boiler's internal sensors detect that the heat is increasing much faster than the water can carry it away. The most common reason is a restriction in water flow, often caused by a failing pump or a build-up of sludge and debris blocking the narrow pipes inside the heat exchanger.
This issue often surfaces in autumn when the heating is turned back on after a long summer break, as pump components can seize or sludge can settle during periods of inactivity.
DIY fix possible
Check that your boiler pressure is between 1.0 and 1.5 barEnsure all radiator valves and isolation valves are fully openCheck for any air trapped in the system and bleed your radiators
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like F41 — no call-out fees, no surprises.
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Ferroli Bluehelix Tech is discontinued — time for a new one?
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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