How much does it cost to fix boiler error code E 34?

Typical repair cost for the boiler E 34 fault is £150-250 including labour.

E 34 Emergency

Boiler Fault Code E 34

Also written as E34 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 31 August 2026

Fault code E 34 appears across 2 boiler brands 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 has lost its connection to a safety sensor that monitors the exhaust fumes, causing it to shut down to prevent unsafe operation. (As reported on Chaffoteaux Minima HE System 24)

Pick your boiler brand for the E 34 fix

Ariston E 34 1 model Chaffoteaux E 34 2 models

Source

Information for the E 34 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 31 August 2026