Climate Control

HVACR Tech Tip: When Should a Catch-All Filter-Drier be Changed?

When should a catchall filter-drier be changed? Tecnician working on HVAC unit - Parker Sporlan, Parker Hannifin 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.


How the Catch-All works

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.



When should a Catch-all filter drier be changed. Sporlan cutaway of catch-all filter-drier- Parker Sporlan, Parker Hannifin



  • Stage 1 - Porous molded Catch-All HH Core filters the vast majority of particles. 

  • Stage 2 - 10-micron filter to capture all but the finest particles. 

  • Stage 3 - 1-micron final filter to capture the remaining particles. 


Removes acid

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.

System start-up

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: 

  1. Did the See-All indicate moisture was present?

  2. Was the system open during service?

  3. Were there any unusual circumstances that could have permitted moisture to enter the system? (ruptured chiller or water-cooled condenser; wet conditions in an area where repairs are taking place)

  4. Was there a hermetic motor burn-out involved?

  5. Was excessive compressor heat involved in the failure?

  6. Is the refrigerant oil discolored or found to be acidic? (A Sporlan Acid Test Kit will determine this)

  7. Was it evident that dirt, metal chips or other contaminants were involved in causing the failure?

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.


Use of Suction line filter driers for clean-up after burnout of HVAC systems - Glen Steinkoenig Product Manager Contamination Control Products, Parker Hannifin Sporlan Division Article contributed by Chris Reeves, product manager, Contaminant Control Products, Sporlan Division of Parker Hannifin





For more articles on climate control:

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

Technologies for Drying Compressed Air: Aftercoolers and Coalescing Filters

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

Clean-up Procedure for Refrigeration and Air Conditioning Systems

Compressor Overheating Is the Number-One Refrigeration Problem

Six Reasons Why CDS Conversion Reduces Costs

How to Use the Smart Service Tool Kit for HVACR Diagnosis


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Comments for HVACR Tech Tip: When Should a Catch-All Filter-Drier be Changed?

Nigel Bourke
We use banks of the 2" Sporlan Catchall ammonia liquid line filters on all or our liquid lines in our vast industrial system and they are an excellent product for keeping the system clean.
I am trying to find information on the filter mycron rating.
Chris Reeves
Thanks for reading the blog Nigel.

These core style filter-driers will capture particles effectively down to about 40 microns.

Best regards,

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