D4 271 High
Your boiler has detected that the water is heating up too quickly or isn't circulating properly, causing it to shut down to prevent overheating.
Technical description: Actual temperature differential between flow and safety temperature sensor is too high
Typical repair cost: £120-350 (including labour)
DIY fix possible
Check that your radiator valves and any isolation valves are fully openEnsure your system pressure is topped up to between 1 and 1.5 barBleed your radiators to remove any trapped air that might be blocking circulation
Protect yourself from future repair bills
A boiler cover plan would cover faults like D4 271 — no call-out fees, no surprises.
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Parts commonly replaced
- Circulation Pump
- Flow/Return Temperature Sensors
- Main Heat Exchanger (Flushing)
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