How much does it cost to fix Ariston error code 40 ❍, 50 ❍, yellow ❍?

Typical repair cost for the Ariston 40 ❍, 50 ❍, yellow ❍ fault is £120-250 including labour.

40 ❍, 50 ❍, yellow ❍ High

Ariston 40 ❍, 50 ❍, yellow ❍ Fault Code

Q: What does the Ariston 40 ❍, 50 ❍, yellow ❍ fault code mean?

Your boiler is struggling to pump water around your heating system correctly, which is preventing it from heating your radiators or taps effectively.

Also written as 4050YELLOW — same fault.

The Ariston 40 ❍, 50 ❍, yellow ❍ fault code means: your boiler is struggling to pump water around your heating system correctly, which is preventing it from heating your radiators or taps effectively.. It appears on 1 Ariston model in our database.

Technical description: Insufficient circulation

Typical repair cost £120-250 (including labour)

DIY fix possible

Check your radiator valves are fully openCheck all radiators for trapped air and bleed them if necessary using a radiator keyEnsure your system pressure gauge is between 1 and 1.5 bar, and top up using the filling loop if it is too low

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Ariston models that show the 40 ❍, 50 ❍, yellow ❍ fault code

Click a model for the full fault code list and model-specific repair notes.

Clas One Repair: £120-250

Source

Ariston 40 ❍, 50 ❍, yellow ❍ fault code information on this page is sourced and cross-checked against the official Ariston service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026