Hi and welcome to the forum. Your Clayton furnace is a very good unit. In my opinion, the Clayton furnaces are the best. Once you get the hang of using your Clayton, you'll love it! I'm not clear as to whether you have the optional Clayton combustion draft fan kit with thermostat, but I would highly recommend getting it and having it installed, if you plan on mainly burning wood.
This link is broken, either the page no longer exists or there is some other issue like a typo.
Here is a post that may help you. CLAYTON FURNACE FIRED ON WOOD
Explain what you mean by the damper. Is it a manual draft damper installed into the stovepipe or an automatic barometric draft regulator? Some pictures would really help. Do you have the electric combustion fan/limit kit, with thermostat, or just the air draft spinner between the cast iron doors and the spinner on the ash door?
Either way, we could get you tuned in short time for a really efficient heating appliance, that you'll be very happy that your former guy installed for you.
I'll be checking back later to help you out.