n1 Low

Boiler Fault Code n1

Also written as N1 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code n1 appears across 2 boiler brands and 2 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler is currently operating in its base 10kW heating mode, which is a standard status indicator rather than a fault, meaning the appliance is functioning correctly. (As reported on Protherm 100EC)

Pick your boiler brand for the n1 fix

Glow-worm n1 1 model Protherm n1 1 model

Source

Information for the n1 fault code is sourced from the official service / installation manual for each model that displays it. Read more about how we source fault codes →

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