BoilerFaultCodes L.320 High
Boiler Fault Code L.320
Also written as L320 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code L.320 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 water pump is struggling to spin, likely due to debris or inactivity, so the system is currently trying to clear itself to get your heating and hot water back on. (As reported on Vaillant ecoTEC Plus 836)
Pick your boiler brand for the L.320 fix
Source
Information for the L.320 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