BoilerFaultCodesYour boiler has shut down because a safety sensor has detected that the main heat exchanger is getting too hot.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Overheating protection on – primary heat exchanger has responded
What causes this fault?
This fault occurs when a dedicated safety fuse inside the main heat exchanger melts because the component has reached an unsafe temperature. The most common reason is a buildup of limescale or sludge that restricts water flow, causing the metal to overheat and permanently blow the fuse. Unlike a standard overheat, this is a one-time safety device that cannot be simply reset.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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A boiler cover plan would cover faults like F.76 — no call-out fees, no surprises.
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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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