D4-A Dryer-Filter-Regulator Operator’s Manual


Dryer-Filter-Regulator Model 4076

Start-Up Procedure

  • Locate the dryer in a cool, dry place, close to the point of air use. Do not enclose the dryer in a cabinet; keep it accessible and well ventilated.
  • Connect a compressed air supply to the D4-A’s inlet and turn it on.
  • Adjust the built-in regulator to throttle the flow.
  • Observe the humidity indicator plug. It should indicate a relative humidity of 60−70%.
  • Connect the downstream airline to the D4-A’s outlet. Purge the airline with a brisk flow before making final connection to the air bearing.
  • Adjust the regulator to the desired pressure.

NOTE: An alternate source of clean, dry air may be connected to the auxiliary inlet/shuttle valve at the D4-A’s outlet. This will simplify periodic shutdowns for dryer maintenance, and also provide a reserve air supply in the event of primary-air-source failure. Many customers use a tank of dry nitrogen gas in this application.


  • Drain the dryer (Item 1) and five filter bowls (Items 5, 6, 8, 9) daily.
  • Check the humidity indicator plug (Item 17) daily. Take action if an increase of indicated humidity is noted.
  • Check the level of desiccant tablets in the dryer column once a month, or if the indicated humidity starts to rise.
  • Change the filter elements once a year. Contact Professional Instruments to order replacements.

Replacement Kits

  • Filter kit includes (1) coalescing element, for Item 6; (1) activated carbon element for Item 8; and (3) particulate elements for Items 5, and 9.
  • Hydrosorb desiccant, 12 pounds.

NOTE: If the D4-A receives air from a clean, dry air supply, the dryer will probably produce no effluent to drain away. Daily maintenance should still be performed. In addition, the desiccant tablets should be changed annually, since they may become oil-saturated, which will diminish their effectiveness.

A humidity alarm is available from Professional Instruments that monitors airline humidity electronically, sounding an alarm when a field-settable humidity level is exceeded. Contact us for more information.

[file] D4A4076Manual.pdf