Boiler Fault Code 16-17

Also written as 1617 — same fault.

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

Fault code 16-17 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 detected that dangerous exhaust fumes are being blown back into the appliance instead of exiting through the flue safely. (As reported on Remeha Gas 350)