BoilerFaultCodesYour boiler has detected that the water temperature is too high, often caused by a lack of circulation or a blockage within the system.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Flow sensor temperature exceeded
What causes this fault?
This fault occurs when the water leaving the boiler gets too hot too quickly, causing the system to shut down for safety. The most common reasons are a pump failure that stops water from moving or a blockage like sludge or trapped air preventing flow through the heat exchanger.
This issue is more common when the heating is first turned on after summer, as the internal pump can seize up after long periods of inactivity.
DIY fix possible
Check that all radiator valves are fully openEnsure the boiler pressure gauge is between 1.0 and 1.5 barSwitch the boiler off and on again to see if the fault clears after cooling
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 E18 — no call-out fees, no surprises.
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Vokera Hydra 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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