Faulty temperature sensor
The actual temperature of hot water is determined by the boiler according to the temperature sensor. Because if for some reason receives incorrect readings. the boiler can work incorrectly in the hot water preparation mode. Temperature sensor is a thermistor with a temperature dependence of resistance. Checking such a sensor is to measure its resistance at a known temperature. In Baksi boilers NTC sensors are installed with inverse dependence of resistance on temperature. At room temperature sensor resistance should be approximately 10 kOhm, at 45 degrees 4.3 kOhm.
Appliance doesn’t work, but code on the display? All the values for Ariston models you can find in the table below. But first restart the technique to rule out system failure. For this press the “Reset” button.
Error codeWhat does it meanHow to fix the problem
- Gas valve.
- Install the coaxial chimney. Clean debris from the pipe, adjust the location of the pipe.
- Open gas valve.
- Inspect ionization sensor. Clean its contacts in case of oxidation. Sensor must be 8 mm away from the comb.
- Retighten the connections of the electrode and the control module.
- Adjust the gas supply. There may be too much pressure on the valve.
- Clean the filter from clogging.
- Check the heat exchanger. Scale build up leads to lower head and poor heat dissipation. Dismantle the assembly and flush the coil with chemicals.
- Run diagnostics of the pump operation. Adjust its speed.
- Check the temperature sensor and electronics board.
- Bleed the system. Some models have a special button for this. On an Egis Plus 24, press mode for a few seconds. Press Reset on Ariston Uno and Mathis. Afterwards check if the pressure is restored to 1-1,2 bar.
- Use the Maevsky cocks if the pressure gauge rises. They are located on each radiator to evacuate air from the system.
- Inspect the secondary heat exchanger. Its damage can cause cold and hot fluid to mix, causing the pressure to rise. Then replace the assembly with a functioning one.
- Hold a lit match to the inspection window for checking. If the flames deflect to the side, there is a draft. If it burns flat. no.
- Clean the chimney shaft from soot and debris. Condensation can build up in the coaxial pipes.
- Inspect the draft sensor. Check if it works.
- Measure the line voltage. If you experience frequent malfunctions, connect a stabilizer.
- Reverse the plug in the socket.
- Inspect the ionization sensor. Clean the contacts of the gas valve and make sure they are seated properly.
- ionization sensor;
- of the gas valve;
- Smoke Removal.
Those models that do not have a display show problems by flashing the indicators on the panel.
What light bulbs are flashing | What it means (⊗ blinks) | |||||||
40 | 50 | 60 | 70 | 80 | 90 | Card. 1 | Card. 2 | |
⊗ | ⊗ | System overheating. | ||||||
⊗ | ⊗ | ⊗ | Disturbed flow of the coolant. | |||||
⊗ | ⊗ | ⊗ | Heating resistor short circuit or breakage. | |||||
⊗ | ⊗ | ⊗ | Hot water thermistor short circuit or breakage. | |||||
⊗ | ⊗ | Control board malfunction. | ||||||
⊗ | ⊗ | ⊗ | ⊗ | ⊗ | ⊗ | Five times restart of the unit. | ||
⊗ | ⊗ | Control unit malfunction. | ||||||
⊗ | Problems with ignition. | |||||||
⊗ | ⊗ | ⊗ | ⊗ | Parasitic flame. The system locks the flame although the gas is shut off. | ||||
⊗ | ⊗ | ⊗ | ⊗ | Flame failure. | ||||
⊗ | Trouble with the smoke evacuation. |
Now you understand why the red light or other indicators are on. Let’s elaborate on the frequent restarting of equipment. Why does it happen? Check that “Comfort” mode is not activated. In such cases, the boiler automatically turns on and off, adjusting.
Faults of some versions of Ariston
a01. malfunction at ignition. First of all you need to check if the phases are properly connected. For 220/1f boilers it is enough to pull out the plug and insert it into the socket, turning it upside down by 1800. As a rule, it helps to eliminate the problem.
Probable causes: unstable supply voltage, incorrect operation (or failure) of ionisation sensor.
e34. The “culprit”. pneumo relay 108. pressure in the heating system is below the critical value. sp2. Error appears after the second unsuccessful attempt to start the boiler.
Probable causes: blocked gas main, sudden drop in pressure in the gas main, low pressure in the water main.
H45 (or 54).NTSc sensor gives the error. In case of leakage in the safety valve, it is enough to replace the seals. Functionality of the sensor is determined by a multimeter. if the resistance on the contacts is unstable, it is rejected.
Indication of errors Ariston on the panel of boilers without LCD (by the example of EGIS)
Control panel indicators | Error description ( ⊗. flashing) | |||||||
40 | 50 | 60 | 70 | 80 | 90 | |||
⊗ | ⊗ | Temperature too high (overheating) | ||||||
⊗ | ⊗ | ⊗ | Insufficient coolant flow (circulation problems) | |||||
⊗ | ⊗ | ⊗ | Open or short-circuited heating thermistor | |||||
⊗ | ⊗ | ⊗ | Breakage or short circuit of the DHW circuit thermistor | |||||
⊗ | ⊗ | Internal board error | ||||||
⊗ | ⊗ | ⊗ | ⊗ | ⊗ | ⊗ | than five attempts to restart the boiler | ||
⊗ | ⊗ | Electronic board malfunction | ||||||
⊗ | Ignition failure | |||||||
⊗ | ⊗ | ⊗ | ⊗ | Parasitic flame (flame when the gas valve is closed) | ||||
⊗ | ⊗ | ⊗ | ⊗ | Flame separation | ||||
⊗ | Smoke exhaust error |
Ariston boiler, error codes with explanations and repair examples
If the gas boiler is malfunctioning, the indicator displays an error message. Knowing the value of the displayed error code, the technician determines the direction in which to look for the malfunction.
Good day or night dear readers. I am sure that if your gas boiler is sick, you will not leave it alone at night. Swim. know! So, to help you with a thermometer, looking at the value of which you can determine where the pain
This thermometer is an indicator on the boiler control panel and if you know the value of the error code that the boiler electronics gives you, this can greatly facilitate the task of searching for faults.
Also it will not be superfluous to know where and which sensor is located.
Because before you start with the error codes, you should know that the brains of the boiler is oriented to the indications of various sensors and sometimes the defect in the sensor itself can lead to an error.
If an error code appears on the screen of an Ariston two-circuit gas boiler, it is recommended to restart the equipment to rule out the possibility of a system failure.
To do this you should press the “Reset” button. If this does not help, then the system signals a real error.
Below we will describe the errors in the following order:
These faults are common to all Ariston models (e.g. Uno 24ff, BS24 kw etc.).д.)
- sp 3 (5p3). for Ariston Class Evo The flame bursts. Check fuel valve for proper operation. Check coaxial pipe installation, remove blockage. Low gas pressure might be a problem.
- 501 No ignition. Check that the gas feed tap is open. Inspect ionization sensor. clean contacts and tighten wiring if necessary.
- 607 Fan relay malfunction. Install a new element.
- 101 Overheating protection has tripped. Adjust the gas supply. Clean the filters from debris. The heat exchanger may be clogged with limescale, resulting in poor heat output and reduced head. Then clean it with special reagents. Diagnose pump functioning, adjust mode. Check temperature sensor and control board.
- 102 Heating system NTC thermistor defective. Check the thermistor for a short circuit Voltage in the 0-5 volt range causes this error.
- 103, 104, 105, 106, 107 Overheating, low fluid pressure or reduced fluid volume. Bleed excess air from the system. Make sure the pressure is between 1-1,2 bar. Check system for leaks: heat exchanger; expansion vessel; pipes, radiators.
- 108, 111 Pressure in the heat exchanger has dropped. There may be airlocks in the system. Remove them with a Maevsky valve. Inspect the system for leaks. Eliminate them.
- 109 Pressure is very high (over 3 bar). Check the integrity of the water circuit. Damage can cause the hot and cold fluid to mix and increase the pressure. In this case you will have to replace the heat exchanger with a new one.
- 110 The thermostat has failed. Check if the thermistor is well connected. Replace part.
- 112 Return temperature sensor malfunction. Diagnose the sensor and its wiring. Replace a broken part.
- 114, 116 No communication with external temperature sensor. Check sensor wiring connections.
- 117 Weak fluid circulation. Reload the gas boiler.
- Short-circuit or interruption of the connection to the DHW sensor. Check wiring, check connection.
- 302 No communication with electronic module. 303 Tighten contacts or replace defective component.
- 303, 304 The electronic board is defective. Replace board with new one.
- 307, 308 Trouble with electronic module. Perform reset. hold down “reset” button.
- 601 No draught. If there is no draught, check the chimney and clear any blockages. If you have no draught, check the efficiency of the draught sensor.
- 604 (yellow light on) Fan malfunction. Unit is not turning on Check that the fan, pressure sensor and control board are working properly. Replace elements with new ones.
- A01 (for boilers with electronic ignition) Failure to ignite. Probably the reason lies in voltage fluctuations. install a stabilizer. Check ionisation sensor, clean contacts.
- E34 The pneumo relay is broken. Replace the part.
- Unable to re-light the burner. Fuel valve should be unscrewed more. Check: ionisation sensor; gas valve; quality of exhaust pipe. Replace the broken parts.
- 6p1, 6p2 Poor ventilation in the room or bad draft. Check the chimney, check the ventilation, open the ventilation window. Check the relay connections.
- 608 The fan works properly, but the pressostat does not work. Check the pressostat and its wiring.
- H45 No warm water or thermistor problem. Diagnose DHW flow sensor, thermistor and safety valve. Fix the broken wiring, replace the broken element.
Among the range of Ariston there are lines, boilers which do not have a liquid crystal display.
Light indication warns of an error:
Please note! It is recommended to call in a service technician to replace faulty elements.
Trouble with multi-zone control (error 7)
Ariston boilers allow dividing the home into zones, each with a different heating mode.
If there is a problem with one of the sections, the system accurately identifies the fault, so the repair of a particular circuit can be carried out without interfering with the other parts of the heating network that are working normally.
- Fault 0X. Problem with the supply temperature sensor in zone X. The contacts of the sensor have to be checked or the part has to be replaced.
- Error 1X. Same problem but with return sensor.
- Error 2X. Overheating in zone X detected. The first thing to do is to check the operation of the thermostat responsible for this section. It could just be a loose contact or component breakage. If it works properly, you need to change the settings.
- Error 50. Hydraulic circuit error. You need to set the correct type of connected hydraulic module (menu parameter 720). If there is no error here, the problem is in the settings of the circuit itself.
Faults of gas boilers Ariston and instructions for their elimination
The Italian brand Ariston, which conceals the world-famous manufacturer of household appliances Indesit Company, has been designing and manufacturing gas-fired heating boilers since the mid-1970s.
Structural division of Indesit Company is Ariston Thermo Group, whose gas boilers have become popular in connection with the intensive individual construction of residential buildings, as well as the unsatisfactory work of centralized heating systems in apartment buildings.
In this review, we will consider some models of this brand, as well as their technical abilities. The operating instructions will be attached below.
Troubleshooting and repair of boilers Ariston
To quickly understand what happened to the heating device and why the two-circuit gas boiler does not heat hot water, it is worth familiarizing yourself with the list of errors Ariston boiler, grouped by nodes. In some cases, error correction, troubleshooting of gas boiler Ariston can be done by yourself, including the replacement of parts.
Error 101 of gas boiler Ariston 24 ff, decoding
The list of error codes begins with 101. If on the equalizer (scoreboard) of the Ariston 24 ff device this code is displayed, it indicates overheating of the coolant. Failure occurs due to:
- High pressure in the area of the gas valve;
- Insufficient speed of water movement (such problem appears because of clogs in the filter, scale, pump breakage);
- Breakdown of the temperature sensor.
Read more: Why does the gas boiler go out?? Main Causes
Fault 103, 104, 105, 107. What to do
Faults 104, 103, 105 or 107 are displayed in case of incorrect fluid flow, flow restrictions or flow failure. Difficult media movement can be caused by airlocks in the system.
There is a simple solution: for a two-circuit boiler 24 kW. press “Mode” for ten seconds; for Ariston Uno. hold “Reset” for about six seconds.
After these actions, the pumping device will run for five minutes, without ignition pumping air. After the procedure it is worth evaluating the pressure. The normal value is 1.2 Bar.
Fault 108, how to fix it
Fault 108 is caused by low pressure in the heat exchanger, the tank, the pipes, the fittings on the gas boiler or the causes mentioned in the previous paragraph. Error code 108 means that it is worth checking the tank and other parts for leaks, make sure the diaphragm part in the expansion tank is failing.
Error Code 109
Error 109 on the Ariston indicates excessive pressure (greater than 3 bars). To fix this problem it is necessary to bleed (use the Mayevsky tap). The second reason for the 109th failure could be a broken heat exchanger mixing water of different temperatures.
Error 302
Such a failure indicates that the display and control board are not communicating properly. Error 302 caused by disconnected/oxidized contacts. At such malfunction it is possible to try to make repair of gas boiler Ariston with your own hands. For this purpose it is necessary to check reliability of connection of contacts and if it is necessary to clean them.
Ariston Vls resetelés, újrainditás Bojlerguru.hu
Error 304
Code 304 is a broken electronic board. It is necessary to find a place of sale of spare parts for gas boilers Ariston and buy a part for replacement.
Error 501, what it means and how to fix it
Error 501 means that the appliance doesn’t ignite because there is no flame to ignite. Turning on the heating unit can be ensured by fixing the following causes of breakdown:
- Absence of gas (it is necessary to check its availability, open the gas valve);
- failure of the control board;
- failure to connect the electrode with the ignition control module;
- breakage of the ionisation electrode (clean the contacts, check the correct location of the comb: the distance between the parts must be eight millimetres);
- decrease in power of the soft ignition system;
- electric current leakage (remove the fault in the mains: the voltage must be 10 V).
Boiler does not ignite, error 607 on the display
If Ariston, the gas two-circuit boiler shows the number 607, the contacts of the fan relay stuck together and it just went off before the ignition.
Sp1 error
Sp1 or 5p1 reflects failed ignition. In this case, 5p2 indicates a repeated unsuccessful attempt to light the wick. Causes:
- Poor air supply;
- Oxidized ionization electrodes;
- Low gas pressure (why the pressure is dropping is difficult to tell right away, so a detailed diagnosis will be needed).
Sp3, 5p3 (flame failure)
If an Ariston 24 wall mounted gas boiler gives one of these designations (error sp3 or 5p3), there may be a flame failure. Fixing the Ariston gas boiler flame detachment error is related to the cleanliness of the chimney. It is too clogged with dust and carbon deposits or improperly arranged, so the fire is immediately blown out or there is a so-called flame breakaway.
Error 025
When the boiler constantly shows the error 025 (it can also look like this: “e25”), it indicates the exceeding of the maximum permissible temperature of the boiler (see. 101 error point).
What to do if the display shows 6p2
A light on the display indicating error 6p2 or 6p1 tells the user that the room with the unit is not properly ventilated: either it is not adequately ventilated or the combustion products are not being drained.
Communication with peripheral devices (error 4)
Ariston gas boilers display error codes for standard peripheral devices. This is to explain the reaction of the boiler automatics to an abnormal situation. In this case consumer can try to repair the fault or hardware conflict independently.
Error 01. Communication problem between the bus and the data transfer device. It can either be caused by a failure of the device itself or by damage to the bus. Repair is only possible in the service center.
Error 02. GRRS/GSM Modem Fault. Need to check its connection or replace the device.
Error 03. SIM card problem. Contact has come loose or the card itself is damaged.
Error 04. Error in data transfer between modem and motherboard. First you need to check the pins. If they are tightly connected, then the modem is defective.
Error 5-406. Data bus problem (interface). Usually the problem is in the loose connections. Less often the bus itself needs to be replaced.
Error 07. Breakage of signal from room temperature sensor. You need to check the connection (wire and pins). If they are in good condition, you need to replace the sensor itself.
What to do if the gas boiler is broken and does not turn on hot water? Instructions for diagnostics and repair
The installation of a two-circuit gas boiler can effectively solve the problem of hot water. But what to do if the hot water in the gas boiler does not turn on? Agree that you should not panic and call the rescue service or service center.

We will get acquainted with a principle of work of two-contour boiler, we will tell about the reasons which can lead to the termination of hot water supply and ways of elimination of the arisen failures.
Understanding the nature of the equipment, you can not only independently identify the causes of failure, but also to eliminate most of the problems, as well as restore the hot water supply in full.