4 11 Medium

Ariston 4 11 Fault Code

Also written as 411 — same fault.

The Ariston 4 11 fault code means: your boiler is struggling to communicate with your thermostat because of a loose connection or damaged wiring in the sensor circuit.. It appears on 6 Ariston models in our database.

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

Technical description: Room sensor circuit open or short circuit ZONA 1

What causes the Ariston 4 11 fault?

This fault occurs when the connection between your boiler's internal computer and the main room thermostat is broken. The most common reason is a loose or damaged wire within the control circuit, or a component failure inside the thermostat itself that prevents it from sending signals to the boiler.

Typical repair cost £120-200 (including labour)

DIY fix possible

Check if your room thermostat or Clima Manager has run out of batteriesEnsure all wired connections to the thermostat are secure and haven't been knockedRestart the boiler using the Reset button to see if the communication error clears

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Ariston models that show the 4 11 fault code

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

Source

Ariston 4 11 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