BoilerFaultCodesAriston 5 01 Fault Code
Also written as 501 — same fault.
The Ariston 5 01 fault code means: your boiler is failing to light the internal flame needed to produce heat and hot water, likely due to a gas supply issue, a blocked flue, or a faulty ignition sensor.. It appears on 15 Ariston models in our database.
Technical description: No fl ame detected
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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A cover plan would handle faults like 5 01: no call-out fees, no surprise bills.
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Ariston models that show the 5 01 fault code
Click a model for the full fault code list and model-specific repair notes.
- Clas HE 24 Repair: £120-250
- Clas HE 28 Repair: £120-250
- Clas HE 35 Repair: £120-250
- Clas HE Evo Repair: £120-250
- Clas HE R Repair: £120-250
- Clas Net One Repair: £120-250
- Clas One Repair: £120-250
- Clas System 28 Repair: £120-250
- E-Combi Evo Repair: £120-250
- E-Combi One Repair: £120-250
- E-Combi One 24 Repair: £120-350
- E-Combi One 30 Repair: £120-250
- Egis Repair: £120-250
- Genus HE Repair: £120-250
- Microsystem 15 Repair: £120-250
Source
Ariston 5 01 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 7 July 2026