It is important to understand the chemical reaction combustion to really appreciate a gas furnace and the importance of combustion air in its operation.
Ty , I am a bit confused, It was my understanding that for 1 cubic feet of natural gas, 10 cubic feet of air was required for complete combustion. 1 cubic feet of propane, 24 cubic feet of air was required for complete combustion. the amount of primary and secondary air contained in combustion air is aprox 60% primary air , and 40% secondary air.for natural gas, this means that 6 cubic feet of combustion air is used as primary air and 4 cubic feet is drawn in as a secondary air. fuel gas+primary air+secondary air= products of combustion
Hi Henry, 1 cubic foot of natural gas per 10 cubic feet of air for perfect combustion. Remember perfect combustion is only obtainable in a laboratory. In furnaces typically 50% excess air is used. (Another 50% for delusion air on old furnaces) www.achrnews.com/articles/105766-btu-buddy-58-combustion-air-for-a-gas-furnace
Also I recomend checking out Gas Heating: Furnaces, Boilers, Controls, Components Book by Jason Obrzut, CMHE And escogroup.org/cosa/combustionanalysis.html
