The Most Vulnerable Point of a Purification System

Where there is compressed air, there is water. Condensation is the moisture that drops out of an air flow as it cools and is therefore a constant threat to cause expensive problems in a compressed air system. Condensate drain systems are necessary to keep water, dirt, wear particles, bacteria out of your system. The problems get worse if you operate lubricated reciprocating or oil flooded rotary screw compressors – which is just about everyone. Compressor oil makes its way into the distribution system with the compressed air. The mixture of oil, water, and dirt tends to build up a sludge that will ultimately jam or clog production equipment, air tools and drains

How big of a problem can this be? That depends on the ambient conditions at the compressor intake. The amount of condensation generated will change according to fluctuating temperatures and the relative humidity of the inlet air. For example, it would not be unusual for a 25 hp air compressor to ingest between 8 and 24 gallons of water a day during the summer season depending on site conditions.

This means that condensate drain systems management is a critical step in supplying clean, dry compressed air to your tools, equipment and system processes. The task of condensate drains is to remove the condensate from the pressurized air system safely and at low expense. The typical compressed air system is designed to have condensation removed at strategic locations. There are drains installed at the after cooler separator, receiver tank, air dryer, in-line filters and at drain points in the piping system. The diagram reflects a basic compressed air system with the amount of condensate removed at key points of the after cooler separator and a refrigerated air dryer.

Condensate drain systems should be considered based on reliability and energy efficiency, not on initial cost. The most vulnerable point in a purification system is the condensate drain system. When installing condensate drains, zero air-loss automatic drains with large drain ports should be utilized. They are full pressure drains, which do not consume compressed air and tend to be very reliable.

Key Benefits of Zero Air-Loss Condensate Drains

  • Saves energy (no air consumption)
  • Very resistant to clogging
  • Removes risk of condensate carry-over
  • Automatically adjusts to condensate levels
  • Long service intervals with safe, easy maintenance

John Henry Foster offers the following three “time proven” drains to handle all your system requirements. Zero air loss drains often qualify for energy efficiency rebates so please inquire with your local power provider.


For more information on our condensate drains, please contact Cheryl in Compressor Parts at 888.681.5739, or visit us at John Henry Foster, 3103 Mike Collins Drive, Eagan, MN 55121,

As a leading provider of premium quality compressed air and automation solutions since 1938, John Henry Foster delivers customized automation products and design-to-build solutions to clients in Minnesota, Wisconsin, North Dakota, South Dakota and northern Iowa. Our talented and innovative employees serve customers in virtually every industry that utilizes motion control technology and power generation.

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