Ariston Combi Boiler A41 error code

Hello Guys,

I have an Ariston Combi boiler & it is giving me a tough time nowadays. The boiler is showing A41 error code while switching itself off immediately. I have restarted the boiled several times but it does not make any difference. I need your help, as I do not know what is wrong here.

Thanks in advance


Hi Bill,

An error code A41 means that boiler’s fan is faulty. Firstly, you have to check the fan by using the voltmeter. In case fan has the required power, but it instantly refuses to run then, you have to replace it. Conversely, if you notice that fan is not getting the required power, do check the printed circuit board (PCB). Well, it is always better to seek help from a professional boiler engineer.

Ariston Eurocombi boiler mechanical timer is not working

Hi All,

The Mechanical timer on my Ariston Eurocombi boiler is not working since last night. I cannot even hear the ticking sound of the timer. Moreover, sometimes the boiler fails to fire up. The boiler is seven years old but it worked fine. Is it a serious issue? Please guide

Thanks for your valuable suggestions


It is considered as one of the common problems in the Ariston Eurocombi boilers. As you said, your boiler is seven years old so it is important to remember that boiler’s mechanical timer tend to develop problems after some years. The common symptoms of this problem are:

  • The boiler’s central heating system is chocked
  • Ignition wires are damaged & need replacement
  • Faulty PCB
  • Thermostat is faulty

In case, these symptoms are causing your boiler’s timer to not work properly then, call a qualified boiler engineer in order to fix the issue.

Ariston MicroGENUS HE boiler error code A03


My Ariston MicroGENUS HE boiler is displaying an error code A03. The boiler is not restarting as well. I have tried to restart it a number of times. Whenever I press the reset button on the boiler, this error code appears again & pump begins to run. Any suggestions what is wrong with the boiler & How to fix it?


Hi Pat,

You will see an error code A03 on the boiler’s display panel when the flow temperature surpasses 103 degree. The problem could be an overheated stat if boiler’s pump is running well. You can fix it easily by following these steps:

  • Firstly, you have to take out a left side board for easy access
  • Secondly, put the wire connection among overheat stat contacts & if your boiler begins working then, overheat stat has to be replaced

In majority of the cases, when users changed the contacts directly to overheat stat, their boilers work properly.

MicroGENUS HE boiler dripping

Hi Everyone,

My three years old MicroGENUS HE boiler has instantly developed a minor leak/drip overnight. The boiler’s heating was off. Everything appears to be working properly but just concerned about the water drips/leaks. I have just serviced the boiler one week ago. Still, I am facing this issue. Please guide!

Thanks in Advance


Hi Richard, firstly it is better to contact a boiler engineer to address the problem in a more wise and professional way. Secondly, to stop dripping/leaking you have to open a bleed valve located on the radiators, as it will release all the water. Please use towels for protecting carpets/floor & something else to catch this water. Furthermore, by releasing the water, you will drop the boiler’s pressure & that has to be sufficient to stop the drip/leak. On the other hand, you can drain the entire system after having the comprehensive knowledge regarding the exact location of the drain valve.

Ariston Eurocombi boiler error code A01

My Ariston Eurocombi boiler is displaying an error code A01 intermittently. I have restarted it but boiler stayed in the lockout mode. What could be a possible reason behind it because apparently everything seems good? Please share your views.



Hi Louis,

According to the user guide, an error code A01 means Boiler Lockout. Generally, there are two reasons behind it:

  • Leakage in the boiler’s heating system
  • Faulty pressure sensor

In case there is, a leakage in the boiler’s heating system, check the pressure device on the boiler. The recommended pressure is 1.5. When boiler’s pressure is too low, it will go into lockout mode. Simply, top up the boiler’s pressure by using the filling loop in you feel that pressure is too low. Conversely, if a pressure sensor is faulty it is better to replace it. I hope that it will make your boiler to work again.

Ariston HE 24 boiler makes loud vibrating noise

Hello Folks,

I have installed an Ariston HE boiler one year ago. The boiler is making a loud vibrating noise from last three days. Well, the noise is periodic, usually happening approximately, a minute after my boiler has successfully fired up, generally lasts less than five seconds, however sometimes go on for more than twenty seconds. I need your help and suggestions.

Thanks a lot


Hi Rob,

At first glance, it seems that problem is due to the circulation issue & restriction, however considering the age of your boiler, I think it does not apply here. It is possibly a blockage in the boiler’s heat exchanger or even a combustion problem. In case, it is a combustion problem, then it has to be checked by a qualified engineer immediately. Apart from this, I am suspecting that there is a blockage in the boiler’s heat exchanger, which is causing the restriction. You can fix it through power flushing. Moreover, it is advisable to power flush your boiler regularly in order to prevent limescale buildup & keep the boiler working at its best.

MicroGENUS HE Boiler no pilot light

Hi Everyone,

I have installed the MicroGENUS HE boiler two years ago. Well, the boiler is behaving differently nowadays but I am not sure what is going on. The boiler has no pilot light. I have restarted it & boiler worked for few hours. Now it is having this issue again. Please help.

Waiting for your help, thanks.


Hi Jake,

If the issue with your MicroGENUS HE boiler is an absence of the flame detection then, you will see an error code 501. There are various potential reasons behind this but; most probably, it is due to a chocked pilot jet. Nevertheless, you cannot diagnose this issue easily. An expert boiler engineer can dismantle your boiler while cleaning out a pilot jet & reinstall it. Apart from this, he will check for something else, which can affect the sequence of ignition & flame detecting abilities of the boiler.

Ariston Clas 30HE 301 Error Code

Hello All,

My five years old Ariston Clas 30HE is displaying 301 error code on the control panel. What is the matter as I have read the user manual but unable to identify the exact reason? How to fix it or should I replace my boiler?

Thank you so much


Hi Ben,

Well, 103 error codes deal with the most disturbing & common issue i.e. faulty PCB. The most costly component of the Ariston Boiler is PCB. It is a circuit board, which gives & takes signals to different electrical components in the boiler. It is important to remember that without PCB the boiler will not work properly. An error code 103 is a warning sign that PCB needs replacement. Do call a specialized boiler engineer & access the loss as at times weak wiring and connections leading to the PCB can be fixed.

Ariston Eurocombi boiler error code 103

Hi Folks,

I have installed Ariston Eurocombi boiler four years ago. From last few days, I am noticing that something is wrong with my boiler as it shows an error code 103 on daily basis. Please share your views along with solutions if someone has faced this issue previously. I am worried please help.

Thanks a lot


Hi James,

An error code 103 on Ariston Eurocombi boiler means insufficient circulation. The two main reasons behind this error code are:

  • Heating system is chocked


Generally, blockages in the heating system originate from heating mud. It is a rust and grime buildup in the boiler, radiator, and pipes. It will not let water to flow properly & therefore an error code 103 is being shown.

  • Issues in the heating pump


When the boiler’s heating pump does not circulate properly, hot water and radiator will not get up to the required temperate.

It is advisable to call a boiler professional to solve this issue in a better way.

Ariston HE 24 error code 604

Hello Guys,

I have bought an Ariston HE 24 boiler two years ago. Everything was working fine until last night. Now, the boiler is showing an error code 604 repeatedly even after restarting the boiler. I am unable to understand the hidden meaning behind this error code. Apparently, everything is looking good. Someone, please guide.



Hi, according to boiler’s user guide error code 604 means that your boiler has insufficient fan speed. Just like an out of order fan, having the fan, which is not working at the right speed, is very risky. Coming to the main issue, whenever an error code 604 appears on boiler’s control panel do take it seriously. Firstly, seek help from an expert boiler engineer in order to assess the loss. Secondly, if the boiler’s fan & other costly parts of the boiler need replacement then do it immediately to prevent further damage.