BoilerFaultCodesYour boiler has sensed that the water inside is Getting too hot and has shut itself down as a safety precaution.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Flow temperature too high
What causes this fault?
This fault occurs when the water leaving the boiler exceeds a safe temperature limit because it isn't moving away quickly enough. The most common reasons are a pump failure that stops water circulation, a blockage in the pipework, or a sensor that is incorrectly reporting the temperature.
This error is more frequent in autumn and winter when the heating is first turned on after a long summer break, as internal pump parts can seize up from lack of use.
DIY fix possible
Check that all radiator valves are fully open to allow water to circulateEnsure your system pressure is between 1.0 and 1.5 bar on the gaugePress the 'Reset' button for two seconds and release
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 E12 — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
Remeha Avanta 18V 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.
Affiliate links — we may earn a commission at no extra cost to you.