Boiler Fault Code N.027

Also written as N027 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026

Fault code N.027 appears across 1 boiler brand and 3 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler is struggling to accurately measure the temperature of the water used for your taps and shower, which will likely result in the water being cold or failing to heat up at all. (As reported on Vaillant ecoTEC Plus 836)