Originally Posted by yuri
Do you have a full set of ductwork on the unit like that of a house? Where did you get the furnace from. The reason I ask is that is a fairly large furnace with a variable speed ECM motor fan and it needs proper ductwork to work against or it may not get up to speed properly. Why do you think it is too slow? Have you done furnace work before? Post some pics of the furnace and ductwork. I am a Lennox tech and know that furnace very well.
Good point,,, ECM motors read the air resistance felt through the blower wheel so with no duct work and open air, it's going to think that there is very low resistance and run at a slower speed naturally.