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.

Fault CodeSection/TypePossible CauseBoiler Model
101Central Heating CircuitOverheatAll Boilers
102Central Heating CircuitPressure sensor errorE-Combi Evo
E-System Evo
Clas He Evo (Combi and system)
103Central Heating CircuitInsufficient circulationAll Boilers
104Central Heating CircuitInsufficient circulationAll Boilers
105Central Heating CircuitInsufficient circulationAll Boilers
106Central Heating CircuitInsufficient circulationAll Boilers
107Central Heating CircuitInsufficient circulationAll Boilers
108Central Heating CircuitInsufficient water (request filling)All Combi Boilers
109Central Heating CircuitSystem pressure greater than 3 barClas net one / Clas one Combi
Clas system one
110Central Heating CircuitCentral heating Flow temperature probe circuit open / short circuitAll Boilers
112Central Heating CircuitCentral heating return temperature probe circuit open / short circuitAll Boilers
114Central Heating CircuitExternal sensor circuit open / short circuitAll Boilers
116Central Heating CircuitFloor thermostat contact openAll Combi and System Boilers
118Central Heating CircuitHeating delivery probe problemAll Boilers
1p1Central Heating CircuitInsufficient circulation indicationAll Boilers
1p2Central Heating CircuitInsufficient circulation indicationAll Boilers
1p3Central Heating CircuitInsufficient circulation indicationAll Boilers
1p4Central Heating CircuitInsufficient circulation indicationClas Net one Combi
Clas one Combi
Clas System one
202D.H.W Circuit2 bottom storage temperature probe open/short circuitClas HE evo
Clas he evo system
E-combi evo
E-system evo
204D.H.W CircuitSolar collector temperature probe open/short circuitClas HE evo
Clas he evo system
E-combi evo
E-system evo
205D.H.W CircuitDomestic hot water in probe open circuitClas HE evo
Clas he evo system
E-combi evo
E-system evo
207D.H.W CircuitSolar collector overheatingClas HE evo
Clas he evo system
E-combi evo
E-system evo
208D.H.W CircuitCollector frost protection temperatureClas HE evo
Clas he evo system
E-combi evo
E-system evo
301Internal printed circuit board (PCB)EEPROM errorAll Boilers
302Internal printed circuit board (PCB)Communication errorAll Boilers
303Internal printed circuit board (PCB)Main printed circuit board (PCB) errorAll Boilers
304Internal printed circuit board (PCB)Too many resets (> 5) in 15 minutesAll Boilers
305Internal printed circuit board (PCB)Main printed circuit board (PCB) errorAll Boilers
306Internal printed circuit board (PCB)Main printed circuit board (PCB) errorAll Boilers
307Internal printed circuit board (PCB)Main printed circuit board (PCB) errorAll Boilers
3P9Internal printed circuit board (PCB)Schedule serviceE-combi one
E-System one
Clas Net one Combi
Clas one Combi
Clas System one
407External printed circuit board (PCB)7 Room sensor circuit open/short circuitClas HE evo
Clas he evo system
E-combi evo
E-system evo
501Ignition and DetectionNo flame detectedAll Boilers
502Ignition and DetectionFlame detected with gas valve closedAll Boilers
504Ignition and DetectionFlame liftAll Boilers
5P1Ignition and Detection1st ignition failedAll Boilers
5P2Ignition and Detection2nd ignition failedAll boilers
5P3Ignition and DetectionFlame cut-ofAll Boilers
604Air Inlet / Flue gas outletInsufficient fan speedCLAS HE R
E-Combi Evo
E-System EVO
Clas HE evo Combi
Clas HE evo System
610Air Inlet / Flue gas outletThermofuse openAll Boilers
612Air Inlet / Flue gas outletFan speed has incorrect measurementClas HE Evo Combi
Clas He Evo System
E-Combi Evo
E-system Evo
Clas net one combi
Clas one combi
Clas system one
701Multi-zone HeatingZone 2 outgoing sensor defectiveE-Combi Evo
E-System EVO
Clas HE evo combi
Clas he evo system
702Multi-zone HeatingZone 2 return sensor defectiveE-Combi Evo
E-System EVO
Clas HE evo combi
Clas he evo system
703Multi-zone HeatingZone 3 outgoing sensor defectiveE-Combi Evo
E-System EVO
Clas HE evo combi
Clas he evo system
704Multi-zone HeatingZone 3 return sensor defectiveE-Combi Evo
E-System EVO
Clas HE evo combi
Clas he evo system
705Multi-zone HeatingHydraulic separation sensor defectiveE-Combi Evo
E-System EVO
Clas HE evo combi
Clas he evo system
706Multi-zone HeatingZone 2 overheatingE-Combi Evo
E-System EVO
Clas HE evo combi
Clas he evo system
707Multi-zone HeatingZone 3 overheatingE-Combi Evo
E-System EVO
Clas HE evo combi
Clas he evo system
411External printed circuit board (PCB)Room sensor circuit open or short circuit zone 1Clas Net One,
Clas One,
E-Combi
E-System
412External printed circuit board (PCB)Room sensor circuit open or short circuit zone 2Clas Net One,
Clas One,
E-Combi
E-System
414External printed circuit board (PCB)Room sensor circuit open or short circuit zone 3Clas Net One,
Clas One,
E-Combi
E-System
701Multi-zone HeatingSend sensor defective (Zone 1)Clas Net One,
Clas One,
E-Combi
E-System
702Multi-zone HeatingSend sensor defective (Zone 2)Clas Net One,
Clas One,
E-Combi
E-System
703Multi-zone HeatingSend sensor defective (Zone 3)Clas Net One,
Clas One,
E-Combi
E-System
711Multi-zone HeatingReturn sensor defective (zone 1)Clas Net One,
Clas One,
E-Combi
E-System
712Multi-zone HeatingReturn sensor defective (zone 2)Clas Net One,
Clas One,
E-Combi
E-System
713Multi-zone HeatingReturn sensor defective (zone 3)Clas Net One,
Clas One,
E-Combi
E-System
722Multi-zone HeatingOverheating in zone 2Clas Net One,
Clas One,
E-Combi
E-System
723Multi-zone HeatingOverheating in zone 3Clas Net One,
Clas One,
E-Combi
E-System
750Multi-zone HeatingAll heating zones lockedClas Net One,
Clas One,
E-Combi
E-System

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