BoilerFaultCodes A1.2 Low
Boiler Fault Code A1.2
Also written as A12 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code A1.2 appears across 1 boiler brand and 6 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler is simply indicating that the burner is currently firing up and running as it should, so there is no fault to worry about. (As reported on Grant Vortex Eco External Wall Hung)
Pick your boiler brand for the A1.2 fix
Source
Information for the A1.2 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