USSC/American Harvest for Central Heat design

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New Member
Jan 22, 2021
Hi All,
I purchase a property a little over a year ago and am in the process of fixing it up. Heating is handled by 2 pellets stoves. They are both setup to just blow air into the room they are in. One of them is an USSC/American Harvest 6500. I have made all the required repairs on it and have been able to program my fuel flow along with hooking it to a thermostat. My plan is to run duct work prior to next winter to use the 6500 as my main central heating source and supplement with my other PP130. I worked for a number of years as a HVAC apprentice and have designed a few system, but never one for a pellet stove. After my research it leaves me with a couple of questions and was hoping someone here could lend a hand.

1. The unit has 2x800cfm blowers. The 1600cfm is enough for all my runs (13x6" flex=1300cfm). I found where it is recommended to increase the size of the return outlet in the unit since the 10x20 opening and small case doesn't flow enough for the blower fans. On the supply side, the opening is even smaller and they say to use a 10" metal round duct to feed your duct system. A 10" round duct shows about 400cfm of flow on all the duct flow charts I can find. 25% of the max room fan output. What am I missing here? What have others done to make sure they get the best airflow?

2. I live in northern Indiana and the house is a 2200 sq/ft ranch. I am hoping that using the 6500 for central heat and the pp130 to supplement in the large living area that will be the farthest away from the 6500 will be all I need for heat. I am out in the country and the house is all electric. I am not wanting to add a propane bill. If the pellet stoves are enough for heat then I can add an air handler with AC. If they aren't enough for heat then I would need to add some kind of furnace. Has anyone here hooked up and run just a 6500 (or 8500. THey have the same CFM etc) to duct work for their home? How did it work? Any pointers to make the system work better?

Thanks for your time