BoilerFaultCodes 395 High
Boiler Fault Code 395
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 395 appears across 2 boiler brands and 5 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler has temporarily lost its internal connection, meaning it cannot properly talk to its main control unit to start up safely. (As reported on Navien NCM 1130HH)
Pick your boiler brand for the 395 fix
Source
Information for the 395 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