BoilerFaultCodes 33/35 High
Boiler Fault Code 33/35
Also written as 3335 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 33/35 appears across 1 boiler brand and 3 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler's air circulation fan has failed, which means the machine has safely shut down because it cannot vent gasses properly. (As reported on Vokera Linea HE)
Pick your boiler brand for the 33/35 fix
Source
Information for the 33/35 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