How much does it cost to fix boiler error code Internal Fault?

Typical repair cost for the boiler Internal Fault fault is £250-450 including labour.

Internal Fault High

Boiler Fault Code Internal Fault

Also written as INTERNALFAULT — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 27 April 2026

Fault code Internal Fault appears across 1 boiler brand and 2 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler's electronic brain is failing to communicate correctly, which has caused the system to stop working to avoid potential damage. (As reported on Worcester Bosch 24CDi BF)

Pick your boiler brand for the Internal Fault fix

Worcester Bosch Internal Fault 2 models

Source

Information for the Internal Fault 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