Boiler Fault Code Er.6

Also written as ER6 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026

Fault code Er.6 appears across 2 boiler brands and 3 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 water temperature is rising too quickly or overheating, suggesting that internal parts are struggling to move heat away from the burner efficiently. (As reported on Vaillant Turbomax Pro 28 2E)