Ariston boilers troubleshooting

Modern boilers come in a variety of modifications. Although they differ in structure, causes of malfunctions and maintenance requirements are similar. The most common causes of faults are described in the following table.

Ariston C boilers troubleshooting

CodeFault description
A 01Overheat lockout
A 03No flame detected within allowed time
A 36Flue pipe too high temperature
A 37CPU fault
A 39PCB fault 1
A 40PCB fault 2
A 41Fan error
E 02No Circulation (check pump and water pressure)
E 04No flame detection
E 05Anti-freeze system, pump only
E 06Anti-freeze system, pump and burner
E 07No water circulation in primary circuit
E 08No water in the primary circuit
E 11Flow sensor open circuit
E 12Flow sensor short circuit
E 13Return sensor open circuit
E 14Return sensor short circuit
E 15Outdoor sensor open circuit (where fitted)
E 16Outdoor sensor short circuit (where fitted)
E 18Flame lift
E 20Flame detected with gas valve off
E 22Faulty air pressure switch
E 23Low fan speed
E 25Tank sensor open circuit
E 26Tank sensor short circuit
E 27Tank fault warning
E 29Room sensor open circuit
E 30Room sensor short circuit
E 33Under floor heating thermostat open circuit
E 34Flue pipe sensor open circuit
E 35Flue pipe sensor short circuit
E 36Flue pipe too high temperature
E 37Communication problem with the main PCB
E 38Reset pressed 5 times within 15 minutes

Ariston E-Combi 24 boilers troubleshooting

ProblemCause/Solutions
Insufficient circulationWater pressure
Bleed heat exchanger
Pump operation
CH return filter for blockages
Circulation around boiler (blockages)
ntc temperature sensors
Insufficient water (request filling)Water pressure gauge for correct pressure
Check for waterleaks on the entire system
CH Flow temp, probe circuit open/ short circuitCheck connections and wiring to temp sensors
Resistance values of temp sensors
Heating delivery probe problemDetails in maintenance guide in installation manual
Floor thermostat contact openCheck terminals TA2 for presence of link wire
EEPROM ErrorCheck the EEPROM connection onto the pcb
Communication errorCheck connection and wiring onto all devices, main and display pcb
Too many (>5) resets in 5 minutesIdentify reason for lockout from table and check for relevant faults
No Flame detectedInsufficient working gas pressure
1st Ignition failedSpark electrode/wiring connectors
2nd Ignition failedIgnition electrode/wiring connectors
Flame cut-offSpark generator/wiring connectors
Check flue system for correct assembly/ termination
Check earth
Gas valve
C02 settings
Soft light rate
Flame detected with gas valve closedIgnition electrode/wiring connectors
Ignition electrode wiring connection onto main pcb
Flame liftInsufficient working gas pressure
Check flue system for correct assembly/ termination
C02 settings
Thermofuse openCheck wiring and connections to thermofuse
Check integriry of main heat exchanger
Fan speed errorCheck fan
Check wiring connections from fan to pcb

Ariston GENUS HE 35 Plus boilers troubleshooting

DisplayCause
A01Three ignition attempts
A03The output temperature exceeds 105°C during operation
A07Too many flame separations over a period during operation
A17Input water circulation fault
A18No water circulation
A33Fan problem
A97Electronic control problem
A98
A99Electronic control problem
SOIFlame not detected on first attempt
S 02Flame not detected on second attempt
S 04Open circuit on Domestic hot water sensor
S 05
S 06Flame separation
S 25Tank sensor open
S 26Tank sensor short circuit
S27Tank overheating
S 30External sensor open circuit
S31
S 80Open circuit or short circuit on room sensor of the Clima Manager remote control
E 02Insufficient water pressure
E 06Open circuit on heating outlet sensor
E 07
E 08
E 09
e noContact open in the floor overheat safety device circuit (Flora room thermostat)
E 20False flame detection with gas valve closed
E 94Electronic control problem
E 95Read error in heating outlet and return sensors
E 995 resets in less than 15 minutes. Resetting by a boiler ON/OFF operation

Ariston microGENUS II 24 MFFI boilers troubleshooting

CodeCause
A01No flame after safety time (7 seconds)
A03The heating flow temperature exceeds 103°C during operation
A97Problem with the electronic monitoring
A98
A99
E02Insufficient water pressure
E04Domestic hot water temperature probe in open circuit
E05Domestic hot water temperature probe short circuited
E06Heating flow temperature probe in open circuit
E07Heating flow temperature probe short circuited
E08Heating return temperature probe in open circuit
E09Heating return temperature probe short circuited
E20Flame detected with gas valve closed
E21Error in the electrical connection (live and neutral crossed)
E33The air pressure switch is closed before the ignition sequence
E34The air pressure switch does not close when the fan runs
E99More than 5 RESETS of the boiler in 15 minutes.