BoilerFaultCodesYour boiler has overheated, causing it to shut down automatically to protect its internal components and your home's safety.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Safety thermostat (41)
What causes this fault?
This fault occurs when the water temperature inside your boiler exceeds a safe limit, triggering a safety shut-off to prevent damage. The most common reasons are a failure of the internal pump to move hot water away from the heat exchanger or a blockage in the system restricting flow.
This issue often surfaces when you first turn the heating back on after summer, as pump components can seize during long periods of inactivity.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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 E9 — no call-out fees, no surprises.
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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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