I have the exact furnace. Excellent little heater, with a few caveats. 1. make sure you use pea size stoker coal (bituminous only) 1/4" x 1-1/4" 2. be sure you are using DRY coal 3. be sure to leave a bed of about 2" + ash in the stove at all times - do not empty burn chamber completely when removing clinker/excess ash. 4. be sure to check oil in transmission case, if it's leaking, get new seals/ seal w/ silicone gasket maker etc or you will ruin a very expensive transmission, use heavier gear oil than what they call for 80w90 is good. 5. put a blower fan on the heat exchanger, the one it comes with is anemic and tends to let the little stove get too hot, it's capable of easily heating an entire house. 6. you WILL have to play with the coal feed and underfire air setting quite a bit to get it to burn right, it's very particular about having the proper mix. 7. DO use a barometric damper set at the factory setting of .04 and then adjust from there; you may have optimal draft much higher or lower than this for whatever particular characteristic of coal you end up burning, different bituminous coals like very different draft setting to prevent outfires. do not use a turn damper the flyash will clog it shortly.
This is the Exact same heater i am currently using to heat my entire house. It's plumbed into my ductwork and i use a different high/low limit fan switch with a BIG squirrel cage fan to move the air. I took the grate off the top and made a rough plenum to adapt to my ductwork and sealed up the grate on the front.
why on earth would you want to burn pellets in it!? you have a very good little coal stoker furnace that runs on some of the cheapest per btu fuel in the world!!! leaps and bounds cheaper than pellets or anthracite. find a source of good bituminous pea stoker coal, if you need help i may be able to help you with that. What is wrong w/ the timer? if it's not working it's usually not the timer, but rather a little switch part of, but available independently from the timer that's much, much cheaper a few dollars vs. a few hundred. I you need the timer, here is a company that may be able to help: http://www.stokerworx.com/parts
BTW: you got a VERY VERY good deal on that stoker. most people arn't letting them go for less than 800 in working condition.