345 Low

Boiler Fault Code 345

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code 345 appears across 3 boiler brands and 4 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler is reporting a connection issue with an optional solar-powered swimming pool heating add-on that does not appear to be installed or is not communicating correctly. (As reported on ECA FELiS FL 50 HM)

Pick your boiler brand for the 345 fix

ECA 345 1 model Viessmann 345 1 model Worcester Bosch 345 2 models

Source

Information for the 345 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 31 August 2026