BoilerFaultCodesHeatline d.71 Fault Code
Also written as D71 — same fault.
The Heatline d.71 fault code means: your boiler has detected that the temperature setting for your radiators has been adjusted to a value higher than what is allowed or expected by the system's memory.. It appears on 2 Heatline models in our database.
Technical description: Maximum temperature setting for heating outlet
DIY fix possible
Locate the heating temperature control dial on the front of the boilerTurn the dial to a lower settingRestart the boiler using the reset button if it does not automatically resume normal operation
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Heatline models that show the d.71 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Heatline d.71 fault code information on this page is sourced and cross-checked against the official Heatline service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 31 August 2026