fireplace drafts

[Cathe Decker]

Hi,
We have a Marco fireplace in our 1998 Gateway by Champion. When our heat runs, and or heat pump, there is always a draft around the fireplace. Not coming from inside...or down from the chimney, but around the edge where the blower vents are and where the whole thing is inserted into the frame.I just cannot figure it out. When we are not using the FP, I hang a big quilt in front of it....
Any ideas?

Cathe