Heat for My Garage

Yeah I agree with that. A hydro carbon consists of carbon and hydrogen. Then when burned its united with oxygen to form carbon dioxide and water. So unless you are burning coal that is saturated with water, there isn't a problem with condensation. I have seen condensation after loading wet coal but after it evaporates, no more condensation.

good to know. learn something new everyday.

I'm going to have to disagree with the premise that water released during combustion isn't an issue with anthracite. It certainly is true that anthracite has a high proportion of carbon, but it also has a significant amount of hydrogen, which forms water during combustion. An approximate chemical formula for anthracite of C240H90O4NS is shown at page 3 of http://www.purdue.edu/discoverypark/energy/assets ... -Oct08.pdf . On an "as received" basis, anthracite also typically has a moisture content of up to 10 percent or more - see "Specifications" tab at http://jeddocoal.com/. That's why there are different ratings for "as received" vs. "dry basis". I wouldn't assume that moisture issues can be assumed to be minor with a coal boiler. If anything, the combination of moisture and fly ash tends to be pretty corrosive, and a good reason to maintain a low limit that inhibits condensation.

Mike

I am not a chemist, but I can confirm that running my Efm at 140 degrees for a few weeks produced strange deposits inside the firebox.