Gatling dome, any info on these stoves?

New to the site, love working on old stoves, bought 4 of these at an auction, they sat in a pole barn, unused since the 70's, 3 of them still had the original paperwork in them, have one in my barn, it will heat a 30 x 40 pole barn(not efficiently though), just wondered if anyone new anything about these stoves

I just installed a Gatling in my garage/studio.
I purchased it from a homeowner in Big Bear, CA.The tag says that it was built by the Energy Research and Development Corp of Wisconsin.
It only draws when the door is open. So I am hoping that the two knobs on the front have some function. What do you think?
Also, if you have paperwork on your stoves, do you also have a user manual? If so, I would really appreciate some background info, as I'll have the stove for the long haul.

the manual only showed how to install the fire bricks, i run mine with the door closed and the knobs almost all the way open to get it to draw