What is a Filter Drier?
Filter driers, also known as filter dryers, are essential components of refrigeration systems, including your HVAC system, designed to remove contaminants and particulates from the refrigerant. A malfunction with the filter drier can result in acid build-up within your HVAC system. Failures can also cause frozen refrigerant, preventing your AC from working properly, and a shortened lifespan for the compressor. Keep reading to learn more about filter driers from Today’s Homeowner’s experts.
Filter driers are devices used in a cooling system that are a combination of filter and dryer (or drier). An HVAC filter is used to remove any particle such as dirt, metal, or chips from entering the refrigerant flow control. The refrigerant filter could be a thermostatic expansion valve or simply a capillary tube.
What Does a Filter Drier Do?
The filter is sometimes also referred to as a strainer. It is critical that these particles are filtered out and prevented from going into the metering device. It can cause blockage to the passage flow of the refrigerant in the AC expansion valve and cause improper operation of the system.
A drier is used to remove the moisture from the refrigerant. Sometimes it is also called a dehydrator or dryer. It is necessary to remove moisture from the system, otherwise it may freeze inside the tube, causing the flow of refrigerant to be restricted. Water in an HVAC system can come from many sources, including system leaks and improved evacuation. Another source is improper handling of polyester (POE) lubricants can absorb and hold moisture easily. This retained moisture can cause systems to freeze and metal components to freeze.
Types of Filter Driers
There are two types of filter driers, including liquid line and section line.
Liquid line filter driers are placed after the condenser coil and before the expansion valve. The liquid refrigerant that flows from the condenser to the expansion valve is filtered from particles and moisture before entering it. A good filter will filter out particles that are 20 micron, or above from the system.
Some higher-end devices have sight glass that enables the technician to look into it to see the level of refrigerant. Some have chemicals in it that indicate the amount of moisture in the system based on the color of it.
The Emerson EK-164 liquid line drier shown below can remove moisture and acid from the liquid refrigerant. It can also remove particles that are bigger than 20 microns from the refrigerant system. It has a maximum operating pressure of 680 psig and is painted with a corrosive-resistance epoxy powder paint. Suitable for outdoor installation.
A suction line filter drier is placed after the evaporator and before the compressor. This device is used to protect the compressor, especially after any failure that contaminates the system. Motor failure in the compressor usually causes acid and other contaminants to be introduced into the refrigerant system. A suction line filter drier works to prevent this breakdown.
FAQ
Are Filter Driers Necessary?
Yes. Filter driers are key components of all refrigeration and air conditioning systems and perform two essential functions: filtration and absorbing contaminants within the system.
What Do Filter Friers Do?
Filter driers have a few main functions, including filtration and contaminant absorption. They work to prevent refrigerant or system freeze-ups and discourage acid formation. Filter driers also prevent corrosion, and help to prolong the life of your compressor.
Which Filter Drier Is Right for My Hvac System?
There are four types of drier filters, including spun copper driers, steel liquid-line driers, steel section-line driers, and steel bi-flow driers. Filter cores also vary, and filter driers can have solid cores or replaceable cores. I recommend consulting a heating, ventilation, air conditioning, and refrigeration (HVACR) tech to know what your system requires.
This article has explored the basics of filter driers, including what they are, functions, and types. If you need more specific information about the filter drier in your system, I recommend calling an HVACR tech.
