Ariston Boilers Error 108. How to fix this quickly and easily


Having an Ariston boiler in your home means that you can enjoy state-of-the-art technology, excellent performance, low energy consumption heating, versatility (a combination or heating only option, indoor or outdoor use, etc), as well as environmentally friendly and modern equipment that will blend in well with your home’s decor. It is a good idea to be aware of the ways in which your boiler can malfunction. This article will discuss a common error with Ariston boilers: error 108. We will explain the causes of this error and how you can solve it in the easiest way.

How to interpret Ariston boiler error codes

Ariston boilers form part of Italian company Ariston Thermo’s heating comfort products. They also manage leading brands in the sector, such as Elco, Chaffoteaux, Cuenod, Ecoflam, Thermowatt, and more. One of the advantages of owning an Ariston brand boiler is that their error code system gives you clear guidance as to what problem your boiler is having. The good news is that error 108 (and all others) in an Ariston boiler can be seen easily as these boilers have a user-friendly display.


Whenever there is a problem with the boiler, it will display a specific error code to give you an idea of what might be causing the unit not to work properly. All that is needed in these cases is to consult the user manual, find the error codes section, locate the error code that your boiler has, and then read the description which also gives you information on how to resolve the problem. This applies to Ariston Clas Premium Evo boilers that get error code 108, but is also applicable to other models from the Ariston brand.

What is error code 108 is and how do I fix it on my Ariston boiler?

Error 108 in an Ariston boiler means that the pressure is too low. In any brand of boiler, pressure that is too low is a common problem. There are always several reasons why a boiler’s pressure can be low, which therefore also means that there are several possible solutions. Let’s take a look at the causes and solutions step by step.

Boiler does not have enough water

The most basic cause of low pressure in a boiler is a lack of water. This is stated in the Ariston manual. Not enough water means that you’ll need to refill the boiler. In most cases, refilling the boiler properly will resolve the low pressure problem and will make the error 108 code disappear on your Ariston boiler.

An important detail to bear in mind is that your Ariston boiler, itself, will warn you that the pressure is low or that it doesn’t have enough water. So, how can tell? Well, you can take a look at the boiler’s pressure gauge. Normally, the pressure gauge should read between 1 and 2 bars. This is the correct pressure for domestic boilers.

If the pressure gauge needle is below 1 bar, however, this means that your boiler is warning you that its pressure is too low, which could be because it doesn’t have enough water. If you heed this warning quickly and fill your boiler up promptly, the boiler won’t have time to display error 108.

In theory, this is a simple and routine procedure, and does not involve necessarily having to call in a qualified professional. All you need to do is locate the boiler filler tap (if you don’t know where this is, it will be in your boiler’s user manual), open it counterclockwise, and then let the water flow in until the pressure rises to a normal level. (Click here if you need to download the manual for your Ariston boiler from the official website in Spanish).


Another important detail: when the boiler has enough water and the pressure gauge needle is between 1 and 2 bars, do not forget to close the filling valve. If you forget to do this, the water will continue to enter the boiler, and the pressure could rise too high, triggering the safety valve and flooding the entire room. Since you obviously don’t want this to happen, make sure you close the tap as soon as the pressure reaches a normal level.

What if my boiler doesn’t fill up even after opening the filling tap?

Sometimes, you might find that even after following the instructions in the user manual and filling the boiler with water to increase the pressure, it doesn’t fill up, even after you have opened the filling tap. Possible solutions here are: you need to activate the water pump (by opening a tap). If it has already been activated, then the filling tap may be faulty. A solution for this would be to replace the filling tap with a new one.


Ariston boiler error 108: Possible water leak

The low pressure may be due to a water leak in the system: in the heat exchanger, pipes, the expansion tank (broken membrane), gaskets, radiators, etc. Sometimes the leak can be fixed, but you will often need to replace it.

Get all the Ariston spare parts that your business needs from Suner.

You can find all the Ariston spare parts that your business needs from the Suner store. Our Ariston catalogue is vast and wide ranging, and includes probes, valves, electronic boards, motors, flow switches, plate exchangers, expansion vessels, and much more.

All our parts are 100% original, and have been manufactured with the highest quality materials and precision designs. Our store features a highly specialized search engine, making the buying process simple, intuitive, and seamless. We ship quickly and safely (with dispatch 24 hours after purchase).

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