The Role Of Filter Driers In Air Conditioning Systems

So-called filter driers are becoming a more and more common part of air conditioning systems--either installed by the manufacturer or added during installation by an HVAC professional. Despite their increasing prevalence, many people fail to understand the role of a filter drier. If you would like to learn more about this helpful component, read on. This article will discuss the role of filter driers in AC systems.

Moisture Absorption

Perhaps the most important job of a filter drier is to help remove unwanted moisture from the refrigerant passing through your air conditioning system. Such water may have a number of difference sources, with system leaks, improper air evacuation, and clogs in the condensate line being among the most common. The task of removing this water is specifically performed by the dessicant material contained inside of the filter drier.

There are two main reasons why water inside of an air conditioning system is bad. First of all, it provides the perfect breeding ground for a whole host of unwanted microorganisms--legionella bacteria being the worst among them. Second, that water has a nasty habit of reacting with polyolester lubricants to form destructive organic acids.

The two most common types of dessicant material that can be found inside a filter drier are activated alumina and molecular sieve. Each has its own unique set of benefits. Molecular sieve, for instance, has the largest water capacity. Alumina, on the other hand, is much more proficient at absorbing any organic acids that may be present.

Contaminant Filtration

The filter drier is also responsible for mechanically filtering out any physical contaminants. A filter drier may accomplish this task by one of two methods: surface or depth. Surface filtration at its simplest comes in the form of a metal mesh screen. Just as with filtration screens in faucets and other plumbing fixtures, this type of filtration acts to prevent particles of a certain size from entering the system and causing clogs and other problems.

A depth filter works on a slightly different model. Here the filter is made up of multiple layers, whose job is to channel both the refrigerant and any contaminants present through an indirect maze of openings. The idea is that, sooner or later, any contaminant will encounter an opening too small for it to pass through, while the refrigerant will still be able to flow freely through other openings. The strongest benefit of depth filters is that they are less likely to suffer from clogs and build-up that impede the refrigerant's ability to flow through the system.

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