Medium Warning
4 11 on Ariston Challenger 80E

Your boiler is struggling to communicate with your thermostat because of a loose connection or damaged wiring in the sensor circuit.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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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 this 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.

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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Related fault codes

4 12View →4 13View →

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