How much does it cost to fix boiler error code E83---121?

Typical repair cost for the boiler E83---121 fault is £120-250 including labour.

E83---121 High

Boiler Fault Code E83---121

Also written as E83121 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 27 April 2026

Fault code E83---121 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 is struggling to manage the internal pressure changes as the water heats up, which is causing the system to shut down. (As reported on Biasi Riva Compact 24S)

Pick your boiler brand for the E83---121 fix

Biasi E83---121 1 model

Source

Information for the E83---121 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