How much does it cost to fix Ariston error code 40-80 (ll-ll)?

Typical repair cost for the Ariston 40-80 (ll-ll) fault is £80-120 including labour.

40-80 (ll-ll) High

Ariston 40-80 (ll-ll) Fault Code

Q: What does the Ariston 40-80 (ll-ll) fault code mean?

Your boiler has stopped working because the water pressure inside the heating system has dropped too low to operate safely.

Also written as 4080LLLL — same fault.

The Ariston 40-80 (ll-ll) fault code means: your boiler has stopped working because the water pressure inside the heating system has dropped too low to operate safely.. It appears on 4 Ariston models in our database.

Technical description: Low water pressure in the heating system

Typical repair cost £80-120 (including labour)

DIY fix possible

Locate the external filling loop, which is usually a silver flexible hose connected to two valves under the boiler.Open the valves slowly to allow mains water into the system until the pressure gauge reads between 1.0 and 1.5 bar.Close both valves tightly immediately after reaching the correct pressure.

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Ariston models that show the 40-80 (ll-ll) fault code

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

Source

Ariston 40-80 (ll-ll) 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