Is the combustion blower set to come on by call of a thermostat? I'm not a fan (no pun intended) of combustion blowers. I think the coal does its best work when left to run steady and not continually revved up then left to cool down by a combustion blower..
Natural draft, a barometric damper and running a pressure of -.03 to -.05 will make best use of your coal. Steady consistent draft pressure will result in steady consistent heat output
Plus it seems that a combustion blower pushing against a manual pipe damper could result in a positive pressure situation in the fire box which means it would leak CO into the living area. Not good..
combustion blower is supposed to come on via T-stat, BUT the relay broke awhile ago, so its just stuck on all the time, however i can just set it at a speed and she stays constant. With this furnace i would have to leave the ash door open all the time to get a full-natural draft up through the coal bed properly, setting the blower at low speed should do just fine, as it can feed a gentle flow of air directly into the coal bed.
no barometric damper on the flue, ill just have to put my manometer on it and play with the manual damper to achieve .03-.05" WC.
thanks for the advice guys, ive burned a little coal before a couple years ago, but this is the first time we are running solely coal for a long period.