Proudly serving Wesley Chapel, New Tampa and surrounding areas.

HVACR Tech Tip: When You Should Change the Catch-All Filter-Drier

HVACR Tech Tip: When You Should Change the Catch-All Filter-Drier

It is important to locate a filter-drier in a refrigeration system. Its role is to remove moisture from the refrigerant and lubricant by absorbing and retaining moisture deep within the desiccant granules.

The blend of desiccants used in the Catch-All is specially formulated for exceptional moisture removal. The high degree of activation ensures maximum water capacity, which means the core removes a large amount of water in one pass, thereby protecting the expansion valve from possible freeze-up. Since the refrigerant must flow through the core, maximum contact between the two ensures rapid system dehydration. 

It is not uncommon to see refrigeration and air conditioning systems that have operated for decades, without any service being performed, and with the Catch-All undisturbed since the original installation. This speaks well, not only for the reliability and durability of all the system operating components but also for the Catch-All which has provided protection to these components over the many years of operation.

The solution to system filtration is the Catch-All Filter-Drier. The Catch-All has been designed to do the job with maximum efficiency. It removes these particles, down to the minimum size, in one pass filtration. Furthermore, the large filtering surface available on the core results in the ability to collect a large amount of dirt with a negligible pressure drop. If plugged, the Catch-All will not burst to allow trapped substances back into the system.

The Catch-All Filter-Drier is unexcelled in acid removal ability. The hydrochloric, hydrofluoric, and various organic acids found in used oil samples are harmful in a system. These acids are absorbed and remain on the desiccant in a manner similar to the adsorption of moisture.

Laboratory tests have shown that the Catch-All Filter-Drier’s desiccant has an acid removal ability superior to other desiccants used in other refrigeration driers. Compared to other filter-driers designed for today’s systems, tests show the Catch-All Filter-Drier removes much more acid (on an equal weight basis). The Catch-All has demonstrated excellent field performance in cleaning up severely contaminated systems, whether due to acid, lubricant breakdown, or to hermetic motor burnout. Its success in field service work and in protecting new systems is largely due to its outstanding ability to remove acid and the products of lubricant breakdown.

At the initial start-up, the Catch-All removed any dirt or excessive moisture that may have been in the system. During the years of operation, the Catch-All continued to provide protection by ensuring that no acid or contaminants formed during periods of high condensing or discharge temperatures. Unfortunately, things do not always go this smoothly and service calls are necessary. This is when consideration should be given to changing the filter-drier. 

Here are some questions that will help determine whether to change the Catch-All: 

If the answer to any of these is “yes,” a new Catch-All is good insurance against a repeat problem. If questions 3, 4 or 5 are answered “yes,” both a suction line and liquid line Catch-All are recommended to remove acids and products of oil decomposition.

Sporlan Bulletin 40-10 outlines the procedure for this type of cleanup. The Sporlan See•All and Acid Test Kits are excellent service tools for determining if a replacement of the Catch-All or other filter-drier is required.

For more articles on climate control:

Using P-T Analysis as a Service Tool for Refrigeration Systems

Use of Suction Line Filter-Driers for HVAC Clean-up After Burnout

How to Use the Smart Service Tool Kit for HVACR Diagnosis