How much does it cost to fix boiler error code 3 0 5?

Typical repair cost for the boiler 3 0 5 fault is £200-450 including labour.

3 0 5 High

Boiler Fault Code 3 0 5

Also written as 305 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 27 April 2026

Fault code 3 0 5 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 computer is experiencing a software glitch or communication error that is preventing it from operating correctly. (As reported on Ariston HS Premium)

Pick your boiler brand for the 3 0 5 fix

Ariston 3 0 5 1 model

Source

Information for the 3 0 5 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