E41 High
Your boiler has sensed an unusual temperature difference between the water leaving it and the water returning, suggesting that water is not circulating through your heating system correctly.
Technical description: Different flow/return temperatures
Typical repair cost: £100-350 (including labour)
DIY fix possible
Check that all radiator valves (TRVs) are fully openEnsure your system pressure is topped up to roughly 1.5 barBleed all radiators to remove trapped air locksRestart the boiler using the reset button
Protect yourself from future repair bills
A boiler cover plan would cover faults like E41 — no call-out fees, no surprises.
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Parts commonly replaced
- Circulation Pump
- Flow/Return NTC Sensors
- Main Heat Exchanger (if blocked)
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