E43 High
Your boiler has detected an unusual temperature difference between internal parts, suggesting that water is not circulating correctly through the system.
Technical description: Different temperature error
Typical repair cost: £120-£350 (including labour)
DIY fix possible
Check that your system pressure is between 1.0 and 1.5 barEnsure all radiator valves and isolation valves are fully openTry resetting the boiler to clear the temporary sensor glitch
Protect yourself from future repair bills
A boiler cover plan would cover faults like E43 — no call-out fees, no surprises.
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Parts commonly replaced
- Circulation Pump
- Temperature Sensors (NTC Thermistors)
- Main Heat Exchanger
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