Err High

Boiler Fault Code Err

Also written as ERR — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code Err appears across 3 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's control panel has developed a fault and can no longer communicate with the internal system, meaning you cannot change settings or operate the unit. (As reported on Glow-worm Easicom 24)

Pick your boiler brand for the Err fix

Glow-worm Err 1 model Heatline Err 7 models Vaillant Err 1 model

Source

Information for the Err 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