BoilerFaultCodesAriston 3 02 Fault Code
Also written as 302 — same fault.
The Ariston 3 02 fault code means: your boiler's internal computer system has lost communication with the display screen, meaning the components cannot talk to each other to start the heating process.. It appears on 14 Ariston models in our database.
Technical description: Comunication error
DIY fix possible
Press the Reset button on the front panel and wait for the boiler to rebootSwitch off the electrical power supply to the boiler at the fused spur for 30 seconds, then switch it back on
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Gas Safe Register →Ariston models that show the 3 02 fault code
Click a model for the full fault code list and model-specific repair notes.
- Challenger 80E Repair: £150-300
- Clas HE 24 Repair: £150-300
- Clas HE 28 Repair: £150-300
- Clas HE 35 Repair: £150-300
- Clas HE Evo Repair: £150-250
- Clas Net One Repair: £120-250
- Clas One Repair: £150-300
- Clas System 28 Repair: £150-250
- E-Combi Evo Repair: £200-400
- E-Combi One Repair: £150-300
- E-Combi One 24 Repair: £120-350
- E-Combi One 30 Repair: £150-300
- Egis Repair: £150-300
- Microsystem 15 Repair: £150-300
Source
Ariston 3 02 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