How much does it cost to fix boiler error code 40 ●, 50 ●, red ●?

Typical repair cost for the boiler 40 ●, 50 ●, red ● fault is £120-250 including labour.

40 ●, 50 ●, red ● High

Boiler Fault Code 40 ●, 50 ●, red ●

Also written as 4050RED — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 27 April 2026

Fault code 40 ●, 50 ●, red ● appears across 1 boiler brand and 1 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler is struggling to pump water around your heating system, usually because there is not enough water in the pipes or a blockage is preventing the flow. (As reported on Ariston Clas One)

Pick your boiler brand for the 40 ●, 50 ●, red ● fix

Ariston 40 ●, 50 ●, red ● 1 model

Source

Information for the 40 ●, 50 ●, red ● 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