BoilerFaultCodes Er 08 + Low
Boiler Fault Code Er 08 +
Also written as ER08 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code Er 08 + appears across 1 boiler brand 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's outside temperature sensor is either broken or sending a wrong signal, which affects how efficiently the heating adjusts to the weather. (As reported on Biasi Advance 25C)
Pick your boiler brand for the Er 08 + fix
Source
Information for the Er 08 + 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 27 April 2026