BoilerFaultCodesAriston B02 Fault Code
The Ariston B02 fault code means: your boiler is not receiving a signal from your thermostat, which means your heating won't turn on even if you try to increase the temperature.. It appears on 6 Ariston models in our database.
Technical description: Room Thermostat
DIY fix possible
Check if your thermostat batteries need replacing.Ensure the thermostat is set to 'Heat' and the temperature is set higher than the current room temperature.Check that the wireless receiver near the boiler is powered on and has a light showing.
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Gas Safe Register →Ariston models that show the B02 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ariston B02 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