Technical Information

Time to Change The Filter Drier: What’s The Right Model And How to Install It?

The right filter drier is essential for the cooling system to work properly.

The filter drier is one of the basic components of the cooling system being responsible to prevent impurities and/or moisture from contaminating the control element (capillary tube or expansion valve) or the compressor itself. Therefore, it’s essential to use a good quality brand and one that’s appropriate for the equipment where it will be installed.

The filter drier is considered a basic component of a refrigeration system.

Presence of minimum trace amounts of moisture is common in refrigeration systems, even after a well performed vacuum process. Therefore, the filter drier is very important.

Apart from moisture, the filter also has the function of preventing the passage of solid particles such as steel or copper metallic burrs, solder residues and others that can cause clogging and other problems.

When moisture or impurities clog the capillary tube completely, a cooling system reoperation is required and it’s vital to change the filter, also never forget that cleaning other components is required.

Often, however, the obstruction is partial, leading to a refrigeration system performance drop. In this case, the problem might be incorrectly attributed to the compressor or the refrigerant charge. Therefore, it’s necessary to make a detailed analysis of the situation before starting the work.

Filter Drier Replacement

Each time that a reoperation of the cooling system is carried out replacing the filter drier with a new one is required, because as the filter becomes saturated with water, the desiccant can no longer absorb moisture – the filter drier can’t be reused.

Never choose the filter drier only by the size, let alone the price. Technical criteria must be observed and the manufacturers’ guidelines of these components since filter compatibility with the refrigerant and lubricant oil must be taken into account, always remembering that only models containing molecular sieve desiccants (MS) should be used.

It’s also necessary to be attentive to the quantity of molecular sieves in the filter, since the choice of an inappropriate model can cause displacement of MS spheres, leading to the release of particles.

On selecting, it’s especially important to pay attention to the refrigerant fluid used in the system. For example, generally filter driers designed for use with R600 (isobutane) are too fragile to work with R134a due to work pressure differences between these two refrigerants. This can lead to wear of the desiccant particles, and residues may cause clogging of the filter or capillary tube outlet. The table at the bottom of this page shows the appropriate models to use with each refrigerant.

For proper operation, the filter drier must be installed in the correct position, which varies according to the type of cooling system. If this is not done, the desiccant particles can be displaced and damage the functioning of the cooling system.



This content is restricted to site members. If you are an existing user, please log in. New users may register below.

*Required field

Have access to exclusive content!

The Refrigeration Club brings together everything you need in one place. Here you can exchange experiences with other industry professionals, find information, tips and capabilities to make your job easier, plus you have access to the latest industry news, updated by market specialists. Sign in and see: the Refrigeration Club was made especially for professionals like you.

You, Entrepreneur

Access to information that will make your business take off. Management techniques, market information and more.

Technical Tools

Applications, e-books, fact sheets and other tools to facilitate your work.

Technical Best Practices

Learn from specialists the best techniques that will make you a professional recognized by the market.


Save your favorite information, tips and videos and quickly access what's most important to you.


Here you can exchange experiences and clarify your doubts with other industry professionals. Join!


This site uses cookies. By continuing to use this site you agree to our use of cookies. Find out more