Fooling around with wood burners

Steve Ebels_3

I've been doing a lot of wood burner installs and setup, mostly hydronic type stuff. I've noticed a lot of difference in combustion chamber residue between various types and I'm wondering what you guys think is the reason. The pics I have here are of a Garn and a Euro style downdraft gasification boiler. You'll notice that the Garn has only dry flaky deposits in the combustion chamber and there are actually patches of bare steel showing. The Euro style unit is caked with creosote. Both these units surpass the EPA standard for emissions so it's not as if one was a piece of junk and the other one high tech. In fact if anything the Garn is "lower tech" from a control standpoint. So my question to you combustion guru's is this. What factors are at work here that keep the Garn firebox so clean?. I am not trying to put one guys product down here just curious as to why I'm seeing these results out in the field. The wood in both units is identical type and moisture content.

EJ hoffman

how about load

is the other one short cycling for some reason? Or flue issues?

hot_rod

perhaps

the temperature of the surfaces has something to do with the build up. My EKO does get thick deposits around the door and cooler spots in the burn chamber. It's rare that I jam the firebox full and run it at the highest temperature.

I wonder a thin coating would be better than bare steel for long life, same with any hydronic HX.

hr

Joe Billow_6

It is heat and burn time. If the first picture is a true down draft then you may never see a nice clean firebox. Down drafts typically burn hotter in a secondary combustion chamber which is where the gasification process is. If the boiler is sized correctly and it burns clean the fire box is really of no importance. If the customer doesn't like it have them throw in a table spoon of creosote reducer on every fill.