Hi, my name is Jeremy and I'm an obsessive wood burner . . .
I've been reading and learning from the fine folks at Hearth.com for the past 6 months and am trying to apply all of this newfound knowledge to our new-to-us house with a central wood furnace in the basement. My latest hook is obsessing on the efficiency of our bare-bones, basic Vogelzang Norseman 2500 furnace. I can literally SEE all of my hard earned, sweat equity flying up the chimney when I burn wood in it.
Aside from not having a secondary air supply (which is another thread, entirely), I'm also bothered by how much ash it leaves in the ash pan. The pan is about 24" x 8" and 2" deep, with a full-coverage rocker grate directly above it. Burning 1 to 2 short, hot fires per day over the past week, it fills up EVERY 2 TO 3 DAYS with large, dark, coarse ash. I compare that to what I used to get in a wood stove - fine, light ash that only had to be emptied every few weeks at most - and I'm sure that it's not burning efficiently. The furnace was designed as a dual-fuel wood/coal burner, and I think the full coverage rocker grate is really aimed at the coal burners out there.
I bought a couple of packs of fire brick from our local home supply store and laid 8 of them down over the rocker grate. The fit was close, but not perfect. There are gaps at the sides of about 3/8 of an inch, but the grate itself is completely covered except for a 4 inch area at the front of the fire box. I left that opening to allow primary air from the ash pan door spin-draft a path to the coals, and so that I could sweep my soon-to-be fine ash into the ash pan below.
One fire later . . . and the ash is a quarter of what it would has been! I think the thermal mass of the brick and the fact that the smaller embers and coals couldn't fall away from the heat through the grate made a big difference. I'm definitely declaring a win before I have any real history with the new setup, but I'm confident that the fire brick is the winner. I even saw an increase in the external flue temp - though only by 50 degrees, so it easily could have been unrelated.
Either way, covering the grate with fire brick burned my fuel more completely and efficiently. Take that, ash hole . . . er . . . I mean, ash grate.
I've been reading and learning from the fine folks at Hearth.com for the past 6 months and am trying to apply all of this newfound knowledge to our new-to-us house with a central wood furnace in the basement. My latest hook is obsessing on the efficiency of our bare-bones, basic Vogelzang Norseman 2500 furnace. I can literally SEE all of my hard earned, sweat equity flying up the chimney when I burn wood in it.
Aside from not having a secondary air supply (which is another thread, entirely), I'm also bothered by how much ash it leaves in the ash pan. The pan is about 24" x 8" and 2" deep, with a full-coverage rocker grate directly above it. Burning 1 to 2 short, hot fires per day over the past week, it fills up EVERY 2 TO 3 DAYS with large, dark, coarse ash. I compare that to what I used to get in a wood stove - fine, light ash that only had to be emptied every few weeks at most - and I'm sure that it's not burning efficiently. The furnace was designed as a dual-fuel wood/coal burner, and I think the full coverage rocker grate is really aimed at the coal burners out there.
I bought a couple of packs of fire brick from our local home supply store and laid 8 of them down over the rocker grate. The fit was close, but not perfect. There are gaps at the sides of about 3/8 of an inch, but the grate itself is completely covered except for a 4 inch area at the front of the fire box. I left that opening to allow primary air from the ash pan door spin-draft a path to the coals, and so that I could sweep my soon-to-be fine ash into the ash pan below.
One fire later . . . and the ash is a quarter of what it would has been! I think the thermal mass of the brick and the fact that the smaller embers and coals couldn't fall away from the heat through the grate made a big difference. I'm definitely declaring a win before I have any real history with the new setup, but I'm confident that the fire brick is the winner. I even saw an increase in the external flue temp - though only by 50 degrees, so it easily could have been unrelated.
Either way, covering the grate with fire brick burned my fuel more completely and efficiently. Take that, ash hole . . . er . . . I mean, ash grate.