I'm glad it's getting warmer. You may want to spin out the ash door spinner a lot more than six turns for the heat you need for the house. The ash door spinner is the throttle control for the Clayton 1600 for burning coal. Once the gases have burned of from the new charge, don't forget to close the draft fan flap so you get maximum air flow through the bottom of the coal. Turn the ash door spinner, count how many turns out and record the performance you get with the outside temperature. This way you will always be able to repeat the results consistently. I know if you get the stovepipe temperature before the barometric draft regulator to 350-450 degrees, your house should be up to temperature with the cold weather you are experiencing. If after a few hours and you have the ash door spinner open all the way out, the stovepipe before the draft regulator still doesn't reach 350-450 degrees and you have a good burning bed of coals, it is time to increase the barometric draft regulator setting. I personally like a setting of .07 to .08. This allows me to throttle back the ash door spinner and sucks the air through the coals harder. I've found due to the V shape of the firebox, the ashes build up faster and needs a little more vacuum to keep it burning good. But, I burn buckwheat size coal. It packs tight and strong draft is needed to keep it going. My chimney is 7" round and 37' high. Every situation is a little different but the procedures are the same. Try this out, be patient, say one or two turns out at a time, wait 30-60 minutes or more for each adjustment, record the results and let us know what you find out.