Regen

I am trying to better understand the regen portion of our md hopper.  Is there supposed to be air flow through the bed that is in regeneration either during the heat up or cool down portion on the regen cycle, or does it rely on just the heater turning on for 1.5 hours to regen and then the heater turning off and the bed just sits there and cools for 2.5 hours with no air going through the bed.