BoilerFaultCodes E83 491 Low
Boiler Fault Code E83 491
Also written as E83491 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code E83 491 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's internal memory backup battery is running low, which means it may struggle to keep the correct time or save your heating schedule during a power cut. (As reported on Potterton Promax 15 & 24)
Pick your boiler brand for the E83 491 fix
Source
Information for the E83 491 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