BoilerFaultCodes 98:1 to 98:5 High
Boiler Fault Code 98:1 to 98:5
Also written as 981TO985 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 98:1 to 98:5 appears across 1 boiler brand 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 detected an internal configuration error or a communication fault with its electronic control system. (As reported on Viessmann Vitodens 300-W)
Pick your boiler brand for the 98:1 to 98:5 fix
Source
Information for the 98:1 to 98:5 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