BoilerFaultCodes 50 70 Medium
Boiler Fault Code 50 70
Also written as 5070 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 50 70 appears across 1 boiler brand and 2 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler is experiencing a communication error with its hot water temperature sensor, which is preventing it from providing hot water correctly. (As reported on Chaffoteaux Serelia 24 MFFI)
Pick your boiler brand for the 50 70 fix
Source
Information for the 50 70 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 27 April 2026