How much does it cost to fix boiler error code 0 then 8?

Typical repair cost for the boiler 0 then 8 fault is £80-150 including labour.

0 then 8 High

Boiler Fault Code 0 then 8

Also written as 0THEN8 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 27 April 2026

Fault code 0 then 8 appears across 1 boiler brand and 2 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 that waste water cannot drain away properly, likely due to a blockage or frozen external pipe, causing it to shut down for safety. (As reported on Saunier Duval Ecosy)

Pick your boiler brand for the 0 then 8 fix

Saunier Duval 0 then 8 2 models

Source

Information for the 0 then 8 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