BoilerFaultCodes 33V DC High
Boiler Fault Code 33V DC
Also written as 33VDC — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 33V DC 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 has detected an electrical signal error inside its internal wiring which is preventing it from starting up correctly. (As reported on Glow-worm 23c)
Pick your boiler brand for the 33V DC fix
Source
Information for the 33V DC 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