The Koker is a furnace, not a stove. The 1536 CFM blower is a big part of that difference. It needs to be drawing air from your return duct, not your basement. Rick, Rev Larry, Greg and VigII are right, you are currently pulling air down your chimney through your damper.
You also need to get a much larger hot air connection to your duct work to get all the heat the blower is trying to wash off the furnace. That single small line is going to offer too much resistance to good hot air flow.
The Koker will keep you very warm when you get it hooked up right.