BoilerFaultCodesAriston 5 02 Fault Code
Also written as 502 — same fault.
The Ariston 5 02 fault code means: your boiler has detected internal flame activity whilst it is instructed to be off, which is a significant safety concern that requires an immediate professional check.. It appears on 14 Ariston models in our database.
Technical description: Flame detected with gas valve closed
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Search the official register for a qualified engineer in your area.
Gas Safe Register →Ariston models that show the 5 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: £150-350
- Clas Net One Repair: £150-300
- Clas One Repair: £150-350
- Clas System 28 Repair: £180-350
- E-Combi Evo Repair: £150-300
- E-Combi One Repair: £150-300
- E-Combi One 24 Repair: £120-280
- E-Combi One 30 Repair: £150-300
- Egis Repair: £150-300
- Microsystem 15 Repair: £150-300
Source
Ariston 5 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