BoilerFaultCodesECA 171 Fault Code
The ECA 171 fault code means: your boiler has detected an external alert or safety signal from an accessory like a thermostat or zone controller, which has temporarily stopped the heating.. It appears on 1 ECA model in our database.
Technical description: Alarm contact 1 active
DIY fix possible
Check if your external room thermostat or programmer has run out of batteries.Ensure all external controls and smart hubs are switched on and connected to your Wi-Fi.Check for any visible damage to the wiring leading from external controls to the boiler.
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ECA models that show the 171 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
ECA 171 fault code information on this page is sourced and cross-checked against the official ECA service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026