Hi. I have a Trane XV90. I keep the fan running all the time, as was recommended with the DC variable speed motor in this model. When not in heating or cooling mode, the fan runs at 30% to keep the system pressurized and the air moving. My question is, does anyone know how to kick the fan speed up to full power with out calling for heat or cool? I have a fireplace heat exchanger linked into the cold air return and want to try to move more air without having to fire up the furnace burner. Thanks for any help.

Your motor is electronically controlled. The parts are very very expensive if they get messed up. Be happy with the 30% or call the company that installed it to see if a professional can rewire around the speed control. This is not a do it yourself thing.

Most of these ICM motors use dip switches to set the air flow, you will need to read the books on you model of furnace.