BoilerFaultCodes H20-986 Medium
Boiler Fault Code H20-986
Also written as H20986 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code H20-986 appears across 1 boiler brand and 6 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler has detected trapped air inside the system, which is preventing water from circulating correctly to provide you with heating and hot water. (As reported on Ideal Mini HE)
Pick your boiler brand for the H20-986 fix
Source
Information for the H20-986 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