For automatic blow downs on a Spirotherm dirt or combo unit, there is a a programmable device called a “Drainmaster” by DynaQuip Fluid Control Systems.  This is for facilities concerned about maintenance on the air/dirt combination units. This is the most simple solution to achieve the result.

A second option can be achieved through a small circulator and filter as shown in the diagram below. For additional information, contact your local Spirotherm rep agency.