Free Shipping Does Not Apply to this Item. There are two hot water boilers: a 100,000 BTU unit and a 170,000 BTU unit. The boilers are exactly the same except the 170,000 uses faster auger motors. By switching the two motors, the boilers can be converted from a 100,000 BTU to a 170,000 BTU or from 170,000 to a 100,000 for minimal cost. The boilers are created with round tanks but use square side panels, which keeps the overall cost to a minimum. The boilers can also be equipped with a domestic coil to help heat your household water. Fueled by corn. Phone order only. Please call our Customer Service Department 1-866-966-2129 to order and for current shipping rates. 100% Manufactured in USA