New Horizon BioMass NextGen 25, Owner'S Manual

1. Fuel sources 

The recommended source of fuel for the BioMass boiler is cut and split firewood that is 
well seasoned, with moisture content between 15% and 30%. Log size should be 
around 6 inches in diameter and about 20 inches in length for the BioMass 40 and up to 
30 inches in length for the Model 60. Smaller size wood can be used as well (it will 
increase power output of boiler), including briquettes, artificial logs, wood pellets, and 
corn cobs with kernels. Additional fuel sources like dry wood chips can be added along 
with dry logs, as well as 50% coal. 
 

2.  Boiler construction and design 

The BioMass boiler is made of ¼” boiler plate steel. The heat exchanger is made out of 
multiple, 3-inch diameter tubes (0.150 inch in wall thickness). Chimney outlet is 6-inches 
in diameter. Special construction of the BioMass boiler allows for a very efficient heat 
exchange from the boiler into the heating system by using multiple water pass trough 
water jacket and counter flow of flue gas. The insulation jacket (made out of 
compressed, mineral wool) minimizes heat loss from the boiler, allowing for the 
maximum amount of heat transfer from the boiler into the heating system.  

3. How the boiler works 

During the gasification process, wood inside the loading/burning chamber is dried and 
gradually gasified as temperature raises on the bottom of loading chamber. The  highly 
combustible gas (in the form of smoke) is drawn down through the ceramic nozzle into 
the refractory-lined secondary combustion chamber with a help of blower, mixed with 
fresh ( secondary) air and burned at very high temperatures. The hot, burned gas (flue 
gas) travels up through the heat exchanger tubes, out the exhaust opening, and into the 
chimney. The temperature of secondary combustion (around 2000 °F) completely burns 
off virtually all smoke and particles and other contaminants. Gasses released from the 
chimney are practically invisible and do not contain unburned particles. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

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