the flugas travels thru a secondary chamber which has a thermostat that turns the fan on when the box gets hot. MH wont blow in an EPA stove that is not overfiring & is a waste of $ unless it saves the stove from overfiring & warping.I did not ask about the Yukon furnace. I asked about the Magic Heat. I was trying to learn how the Magic Heat works, I know how a Yukon works.