I just picked up a Lennox 023 oil furnace for my garage. It has a Beckett AFII85 oil burner. Does this unit have an internal stack control/cad cell in it? The guy I got it from says all he unhooked was the chimney, thermostat and oil line. I thought all oil furnaces had to have one in the chimney? Also, is it ok for the chimney pipe to go straight up and out the roof? I have the manual with it and it shows a couple pics with it coming out the furnace then running horizontal for a few feet before going out the roof. It does not say anywhere that it has to run this way? Thanks for any help.