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

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

Ariston E-Combi 24 boilers troubleshooting

Problem	Cause/Solutions
Insufficient circulation	Water 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 circuit	Check connections and wiring to temp sensors
	Resistance values of temp sensors
Heating delivery probe problem	Details in maintenance guide in installation manual
Floor thermostat contact open	Check terminals TA2 for presence of link wire
EEPROM Error	Check the EEPROM connection onto the pcb
Communication error	Check connection and wiring onto all devices, main and display pcb
Too many (>5) resets in 5 minutes	Identify reason for lockout from table and check for relevant faults
No Flame detected	Insufficient working gas pressure
1st Ignition failed	Spark electrode/wiring connectors
2nd Ignition failed	Ignition electrode/wiring connectors
Flame cut-off	Spark generator/wiring connectors
	Check flue system for correct assembly/ termination
	Check earth
	Gas valve
	C02 settings
	Soft light rate
Flame detected with gas valve closed	Ignition electrode/wiring connectors
	Ignition electrode wiring connection onto main pcb
Flame lift	Insufficient working gas pressure
	Check flue system for correct assembly/ termination
	C02 settings
Thermofuse open	Check wiring and connections to thermofuse
	Check integriry of main heat exchanger
Fan speed error	Check fan
	Check wiring connections from fan to pcb

Ariston GENUS HE 35 Plus boilers troubleshooting

Display	Cause
A01	Three ignition attempts
A03	The output temperature exceeds 105°C during operation
A07	Too many flame separations over a period during operation
A17	Input water circulation fault
A18	No water circulation
A33	Fan problem
A97	Electronic control problem
A98
A99	Electronic control problem
SOI	Flame not detected on first attempt
S 02	Flame not detected on second attempt
S 04	Open circuit on Domestic hot water sensor
S 05
S 06	Flame separation
S 25	Tank sensor open
S 26	Tank sensor short circuit
S27	Tank overheating
S 30	External sensor open circuit
S31
S 80	Open circuit or short circuit on room sensor of the Clima Manager remote control
E 02	Insufficient water pressure
E 06	Open circuit on heating outlet sensor
E 07
E 08
E 09
e no	Contact open in the floor overheat safety device circuit (Flora room thermostat)
E 20	False flame detection with gas valve closed
E 94	Electronic control problem
E 95	Read error in heating outlet and return sensors
E 99	5 resets in less than 15 minutes. Resetting by a boiler ON/OFF operation

Ariston microGENUS II 24 MFFI boilers troubleshooting

Code	Cause
A01	No flame after safety time (7 seconds)
A03	The heating flow temperature exceeds 103°C during operation
A97	Problem with the electronic monitoring
A98
A99
E02	Insufficient water pressure
E04	Domestic hot water temperature probe in open circuit
E05	Domestic hot water temperature probe short circuited
E06	Heating flow temperature probe in open circuit
E07	Heating flow temperature probe short circuited
E08	Heating return temperature probe in open circuit
E09	Heating return temperature probe short circuited
E20	Flame detected with gas valve closed
E21	Error in the electrical connection (live and neutral crossed)
E33	The air pressure switch is closed before the ignition sequence
E34	The air pressure switch does not close when the fan runs
E99	More than 5 RESETS of the boiler in 15 minutes.