Boiler Fault Code E78-212

Also written as E78212 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026

Fault code E78-212 appears across 1 boiler brand and 1 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler is failing to light because it cannot detect or maintain an active flame, causing the system to shut down for safety. (As reported on Potterton Kingfisher MF RSL)