| Fault Code | Section/Type | Possible Cause | Boiler Model |
|---|---|---|---|
| 101 | Central Heating Circuit | Overheat | All Boilers |
| 102 | Central Heating Circuit | Pressure sensor error | E-Combi Evo E-System Evo Clas He Evo (Combi and system) |
| 103 | Central Heating Circuit | Insufficient circulation | All Boilers |
| 104 | Central Heating Circuit | Insufficient circulation | All Boilers |
| 105 | Central Heating Circuit | Insufficient circulation | All Boilers |
| 106 | Central Heating Circuit | Insufficient circulation | All Boilers |
| 107 | Central Heating Circuit | Insufficient circulation | All Boilers |
| 108 | Central Heating Circuit | Insufficient water (request filling) | All Combi Boilers |
| 109 | Central Heating Circuit | System pressure greater than 3 bar | Clas net one / Clas one Combi Clas system one |
| 110 | Central Heating Circuit | Central heating Flow temperature probe circuit open / short circuit | All Boilers |
| 112 | Central Heating Circuit | Central heating return temperature probe circuit open / short circuit | All Boilers |
| 114 | Central Heating Circuit | External sensor circuit open / short circuit | All Boilers |
| 116 | Central Heating Circuit | Floor thermostat contact open | All Combi and System Boilers |
| 118 | Central Heating Circuit | Heating delivery probe problem | All Boilers |
| 1p1 | Central Heating Circuit | Insufficient circulation indication | All Boilers |
| 1p2 | Central Heating Circuit | Insufficient circulation indication | All Boilers |
| 1p3 | Central Heating Circuit | Insufficient circulation indication | All Boilers |
| 1p4 | Central Heating Circuit | Insufficient circulation indication | Clas Net one Combi Clas one Combi Clas System one |
| 202 | D.H.W Circuit | 2 bottom storage temperature probe open/short circuit | Clas HE evo Clas he evo system E-combi evo E-system evo |
| 204 | D.H.W Circuit | Solar collector temperature probe open/short circuit | Clas HE evo Clas he evo system E-combi evo E-system evo |
| 205 | D.H.W Circuit | Domestic hot water in probe open circuit | Clas HE evo Clas he evo system E-combi evo E-system evo |
| 207 | D.H.W Circuit | Solar collector overheating | Clas HE evo Clas he evo system E-combi evo E-system evo |
| 208 | D.H.W Circuit | Collector frost protection temperature | Clas HE evo Clas he evo system E-combi evo E-system evo |
| 301 | Internal printed circuit board (PCB) | EEPROM error | All Boilers |
| 302 | Internal printed circuit board (PCB) | Communication error | All Boilers |
| 303 | Internal printed circuit board (PCB) | Main printed circuit board (PCB) error | All Boilers |
| 304 | Internal printed circuit board (PCB) | Too many resets (> 5) in 15 minutes | All Boilers |
| 305 | Internal printed circuit board (PCB) | Main printed circuit board (PCB) error | All Boilers |
| 306 | Internal printed circuit board (PCB) | Main printed circuit board (PCB) error | All Boilers |
| 307 | Internal printed circuit board (PCB) | Main printed circuit board (PCB) error | All Boilers |
| 3P9 | Internal printed circuit board (PCB) | Schedule service | E-combi one E-System one Clas Net one Combi Clas one Combi Clas System one |
| 407 | External printed circuit board (PCB) | 7 Room sensor circuit open/short circuit | Clas HE evo Clas he evo system E-combi evo E-system evo |
| 501 | Ignition and Detection | No flame detected | All Boilers |
| 502 | Ignition and Detection | Flame detected with gas valve closed | All Boilers |
| 504 | Ignition and Detection | Flame lift | All Boilers |
| 5P1 | Ignition and Detection | 1st ignition failed | All Boilers |
| 5P2 | Ignition and Detection | 2nd ignition failed | All boilers |
| 5P3 | Ignition and Detection | Flame cut-of | All Boilers |
| 604 | Air Inlet / Flue gas outlet | Insufficient fan speed | CLAS HE R E-Combi Evo E-System EVO Clas HE evo Combi Clas HE evo System |
| 610 | Air Inlet / Flue gas outlet | Thermofuse open | All Boilers |
| 612 | Air Inlet / Flue gas outlet | Fan speed has incorrect measurement | Clas HE Evo Combi Clas He Evo System E-Combi Evo E-system Evo Clas net one combi Clas one combi Clas system one |
| 701 | Multi-zone Heating | Zone 2 outgoing sensor defective | E-Combi Evo E-System EVO Clas HE evo combi Clas he evo system |
| 702 | Multi-zone Heating | Zone 2 return sensor defective | E-Combi Evo E-System EVO Clas HE evo combi Clas he evo system |
| 703 | Multi-zone Heating | Zone 3 outgoing sensor defective | E-Combi Evo E-System EVO Clas HE evo combi Clas he evo system |
| 704 | Multi-zone Heating | Zone 3 return sensor defective | E-Combi Evo E-System EVO Clas HE evo combi Clas he evo system |
| 705 | Multi-zone Heating | Hydraulic separation sensor defective | E-Combi Evo E-System EVO Clas HE evo combi Clas he evo system |
| 706 | Multi-zone Heating | Zone 2 overheating | E-Combi Evo E-System EVO Clas HE evo combi Clas he evo system |
| 707 | Multi-zone Heating | Zone 3 overheating | E-Combi Evo E-System EVO Clas HE evo combi Clas he evo system |
| 411 | External printed circuit board (PCB) | Room sensor circuit open or short circuit zone 1 | Clas Net One, Clas One, E-Combi E-System |
| 412 | External printed circuit board (PCB) | Room sensor circuit open or short circuit zone 2 | Clas Net One, Clas One, E-Combi E-System |
| 414 | External printed circuit board (PCB) | Room sensor circuit open or short circuit zone 3 | Clas Net One, Clas One, E-Combi E-System |
| 701 | Multi-zone Heating | Send sensor defective (Zone 1) | Clas Net One, Clas One, E-Combi E-System |
| 702 | Multi-zone Heating | Send sensor defective (Zone 2) | Clas Net One, Clas One, E-Combi E-System |
| 703 | Multi-zone Heating | Send sensor defective (Zone 3) | Clas Net One, Clas One, E-Combi E-System |
| 711 | Multi-zone Heating | Return sensor defective (zone 1) | Clas Net One, Clas One, E-Combi E-System |
| 712 | Multi-zone Heating | Return sensor defective (zone 2) | Clas Net One, Clas One, E-Combi E-System |
| 713 | Multi-zone Heating | Return sensor defective (zone 3) | Clas Net One, Clas One, E-Combi E-System |
| 722 | Multi-zone Heating | Overheating in zone 2 | Clas Net One, Clas One, E-Combi E-System |
| 723 | Multi-zone Heating | Overheating in zone 3 | Clas Net One, Clas One, E-Combi E-System |
| 750 | Multi-zone Heating | All heating zones locked | Clas Net One, Clas One, E-Combi E-System |
Ariston Fault Codes
Welcome to the fault-codes section of this site. The following table or page contains the information required to help repair and diagnose the fault codes being shown on the boiler display. You may be guided through the fault finding sequence or steps, for rectifying your boiler with this fault code. Suggested repair solutions may be provided by a link to a repair page. NB Some fault codes are only applicable to a specific range of boilers only.
Disclaimer: Information on this website is provided for informational purpose therefore we cannot accept liability for subsequent problems. All repair tasks should be carried out by qualified trades people. We may also receive commission payments when you are taken to external websites and complete purchases from third party sellers, once you leave our site, we cannot be held liable for your purchases.