A 39 High

Boiler Fault Code A 39

Also written as A39 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code A 39 appears across 2 boiler brands 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's main internal computer has detected a critical electronic error that is preventing it from functioning correctly. (As reported on Ariston Euro Combi 30 MFFI)

Pick your boiler brand for the A 39 fix

Ariston A 39 2 models Chaffoteaux A 39 1 model

Source

Information for the A 39 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