New heil furnace odor

I had a new Heil furnace installed a couple of months ago and during start up the installer said that there would be some smoke for a couple of minutes.
Well there was some smoke and a burnt smell. Since then every time the furnace kicks on there is still a very slight burnt odor .I called the installer back and he says every thing is working and he can not smell anything. Well we just got back after being gone a week and we had to open the windows the odor was so bad. It is a heil 80% 100,000 btu 2 speed. Anyone had this problem.
Kingnus

80% why do they even allow those units to be sold and installed in this country ?

and no a burt smell is not normal as far as I know

Lou

Smell

Get them back with a Carbon Monoxide detector just in case.