BoilerFaultCodes EE6644 High
Boiler Fault Code EE6644
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code EE6644 appears across 1 boiler brand 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 lost the ability to read the temperature of the water returning to it, so it has shut down as a precaution to prevent overheating. (As reported on Ariston Micro Condens)
Pick your boiler brand for the EE6644 fix
Source
Information for the EE6644 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