5 Common Mistakes You can make while you Install a Filter Drier!


Dry All as a leading manufacturer of Full Range of HVAC&R Line Products is constantly innovating, developing and, designing products to meet the requirements of the industry.

Since its inception, Dry All stakeholders with their most efficient design and R&D Team has always emphasized on producing the latest technology products to meet the challenges of the constantly evolving technology in the HVAC&R industry.

Dry All “5 Common Mistakes” series is designed to help the installer/ technician to avoid common mistakes that one can make during product installation.

The second in the series is on Filter Drier. Here are five common mistakes you can make while Installing a Filter Drier. 

1)   Installing the Filter Drier in wrong direction

Mistake – Installing a Filter Drier in the wrong direction is a complete no-no. All Liquid Line and Suction Line Filter Driers are designed as Uni-Flow except Bi-Flow Filter Driers. Normal HVAC&R cycle moves in one direction and filter driers are designed to be used in one direction only. The inlet of the filter drier has a spring that cushion the desiccant from attrition. The inlet also has filtration media to capture all contamination. This is followed by a desiccant bed comprising of Molecular Sieves and Activated Alumina. The outlet again has final filtration media to filter contamination up to 20 microns.

Consequences– If the technician makes the mistake of installing the drier in the wrong direction, the drier will not work and serve the purpose for which it has been designed. So, no filtration of contamination and no drying of moisture. There can be other problems like pressure drops, contamination escaping the drier, and so on.

Solution– The label of the drier indicates the flow direction and the technician have to be careful to follow the same.

2)   Choosing the wrong model/size of Drier

Mistake – Line size cannot be the only criteria for selecting a drier. For example, if the line size is 3/8”, driers available for the same size are 033, 053, 083, 163 & 303. Technician sometimes to save cost can choose a smaller drier and sometimes in a zeal to clean chooses an over-size drier.

Consequences – A small drier will not serve the purpose for it has been installed. Therefore, no proper filtration and no drying. If oversized, there will be a pressure drop and the system will not work properly.

Solution– Choosing the right size of drier is of utmost importance. The technician can consult the technical catalogue provided by the manufacturer and do his trials and finalize the right size. Dry All provides all technical support to its customer to choose the right model.

3) Brazing Installation Mistake

Mistake – There are many mistakes a technician can make while brazing a filter drier to the system. The most common mistakes are not protecting the connection and the drier joint and secondly not bleeding positive nitrogen pressure.        

Consequences– a) If the joint of the drier body with a connector is not protected with a wet rag or protective clay available these days, the paint at the joint will burn off. This will become a weak area and will start rusting. In some extreme cases, due to excessive heating, this joint may also leak. b) If you miss out to bleed oxygen while brazing, scaling, and oxidation will occur inside the system tubing.

Solution – a) Always cover the Filter Drier with wet rage or protection clay before brazing. B) Bleed nitrogen through the drier during brazing. 

4)   Threaded joint installation

Mistake – Not using the right torque for the installation of Filter Driers with threaded joints.

Consequences- Using the right torque is very important to install a threaded joint Filter Drier. If the torque is less, it will result in a leak. If extra torque is applied, it may break the nut or damage the thread.

Solution – You are required to follow the instructions prescribed by the manufacturer for the threaded joint.  

5)   Avoiding Sight Glass / Liquid Indicator / Moisture Indicator

Mistake – A small window is installed immediately after the liquid line filter drier. This window is called a Sight Glass / Liquid Indicator / Moisture Indicator. The glass window allows the technician to sight the moving refrigerant in liquid form. It is also called a moisture indicator as it has a special paper that changes color based on moisture present in the system and hence also indicates the amount of moisture present in the system. One of the common mistakes is not installing a Sight Glass / Liquid Indicator / Moisture Indicator on the liquid line immediately after the liquid line filter drier. Technician skips installing Sight Glass / Liquid Indicator / Moisture Indicator to avoid an additional cost or sometimes he thinks it’s just not necessary.

Consequences– A periodic check of the HVAC&R System is required and this includes checking the condition of the filter drier and the best indicator of the health of the liquid line filter drier is through the Liquid Indicator. In absence of the same, the technician has to rely on conventional and technical wrong methods to decide on a change of filter drier.

Solution –Always install a Liquid Indicator with good quality moisture indicator immediately after the sight glass. One more solution to this mistake is installing a filter drier with inbuilt liquid indicator/sight glass at the outlet of the filter drier. This helps in saving space, reduce joints, and save money.   

Appeal to the HVAC&R trade Fraternity

If you have any suggestions or recommendations or you would like to add to the above, please do write back to us. Your practical experience and sharing of your knowledge will help the HVAC&R trade fraternity. We look forward to hearing from you.

Stay tuned for more such “5 common Mistakes” writeup on other HVAC&R Line Products.

Technical Inputs for this write up is by Vikash Sekhani, Director Sales & Marketing, Dry All.

Reach Us At

Dry All Liquid Line Filter Driers are available direct to our OEM customers and through our Wholesalers, Dealers across India & worldwide

For more details please visit our website http://www.dryall.net  

You can also contact us at info@dryall.net


The content in this presentation has been prepared by Dry All and is general information about HVAC&R line products. This information is given in the summary form and does not purport to be complete. The information provided is for education purposes only. Before acting on any information, you should consult or take the advice of Dry All Engineers.

Author: Dry All

Manufacturer of "Full Range of HVAC&R Line Products"

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