E125 High
Your boiler has shut down because it has detected it is getting too hot, which is often caused by trapped air or a blockage stopping the water from flowing.
Technical description: Overheat – try bleeding your radiators
Typical repair cost: £80-250 (including labour)
DIY fix possible
Check that all radiator valves and boiler isolation valves are fully open.Bled all your radiators using a radiator key to release any trapped air.Turn the boiler off and on again, or press the 'R' reset button for 5 seconds.
Protect yourself from future repair bills
A boiler cover plan would cover faults like E125 — no call-out fees, no surprises.
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Parts commonly replaced
- Circulation Pump
- Heat Exchanger (Cleaning/Descaling)
- Flow/Return Thermistors
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