BoilerFaultCodes 2128 Medium
Boiler Fault Code 2128
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 2128 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 expansion vessel has lost its air pressure, which means it cannot safely manage the pressure changes in your heating system as it warms up. (As reported on Warmflow 70/90 Combi)
Pick your boiler brand for the 2128 fix
Source
Information for the 2128 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