BoilerFaultCodes 1 to 9 Low
Boiler Fault Code 1 to 9
Also written as 1TO9 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 1 to 9 appears across 1 boiler brand and 1 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 running normally and is in the process of heating up or waiting for a demand for hot water. (As reported on Remeha Quinta 30)
Pick your boiler brand for the 1 to 9 fix
Source
Information for the 1 to 9 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