71 High
Your boiler has stopped running because it senses that even though the burner is lit, the water inside isn't getting any warmer.
Technical description: No primary temperature increase detected
Typical repair cost: £120-350 (including labour)
DIY fix possible
Check that the radiator valves and the main isolation valves under the boiler are fully open.Ensure your system pressure is topped up to between 1 and 1.5 bar.Try resetting the boiler to see if the error was caused by a temporary air lock.
Protect yourself from future repair bills
A boiler cover plan would cover faults like 71 — no call-out fees, no surprises.
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Parts commonly replaced
- Circulation Pump
- Heat Exchanger (Flushing)
- Flow/Return NTC Sensors
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