BoilerFaultCodes D.157 High
Boiler Fault Code D.157
Also written as D157 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code D.157 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's electronic brain is currently unsure which type of gas is being supplied to it, causing the system to lock out for your protection. (As reported on Vaillant ecoTEC plus)
Pick your boiler brand for the D.157 fix
Source
Information for the D.157 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 7 July 2026