How much does it cost to fix boiler error code Error 04?

Typical repair cost for the boiler Error 04 fault is £250-500 including labour.

Error 04 High

Boiler Fault Code Error 04

Also written as ERROR04 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 27 April 2026

Fault code Error 04 appears across 2 boiler brands and 9 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 internal fault that is preventing it from operating, which usually indicates an issue with the electrical system or the main circuit board. (As reported on Atag E32S)

Pick your boiler brand for the Error 04 fix

Atag Error 04 8 models Johnson Starley Error 04 1 model

Source

Information for the Error 04 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