How much does it cost to fix boiler error code Er 25?

Typical repair cost for the boiler Er 25 fault is £450-£900 including labour.

Er 25 High

Boiler Fault Code Er 25

Also written as ER25 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 27 April 2026

Fault code Er 25 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 that the main heat exchanger is getting too hot or is not circulating water correctly, causing the system to shut down for safety. (As reported on Biasi Advance 25C)

Pick your boiler brand for the Er 25 fix

Biasi Er 25 1 model

Source

Information for the Er 25 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