How much does it cost to fix boiler error code 900?

Typical repair cost for the boiler 900 fault is £150-300 including labour.

900 High

Boiler Fault Code 900

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 7 July 2026

Fault code 900 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 an electrical issue where it is not receiving the correct voltage required to run its components safely. (As reported on Heatline Vizo Plus 24)

Pick your boiler brand for the 900 fix

Heatline 900 1 model

Source

Information for the 900 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 7 July 2026