newbie question

[clearblue16]

hello, another question...i have a Hampton HI200 small wood insert....i am trying to maximize the heat output from it....i have very good seasoned wood from 2 years ago that has been covered and in my hands....mostly doug fir....
1. i have a bunch of maple for next year but hardwood will last longer but not put out more heat or is that wrong?
2. draft control...i start a fire, let it run for awhile with the draft full open....hampton says to keep the draft 1/2 open with the blower on....i have been running with the draft full open and the blower on....does it help to close the draft halfway once it really gets going?

thanks!

 

[LeonMSPT]

Dry wood with a constant air supply will likely burn at nearly the same temperatures. The reason hardwood "last longer" is it tends to be more dense than softwoods. You're squeezing more wood into the space when you load it with hardwood.

When burning wood to extract heat from the stove, you're only going to get x BTU's out of the stove. At some point, it's pointless to burn hotter as you're sending lots of heat up the chimney. While it's a decent idea to do this once a day, it's not great to do it constantly. You're wasting the wood and heat.

Most of the EPA compliant wood burners are set up to burn hotter when the air is reduced to them. My own relic from the early 80's gets a hair hotter once I get a secondary burn going and close the air down to the temperature I want it set to.

hello, another question...i have a Hampton HI200 small wood insert....i am trying to maximize the heat output from it....i have very good seasoned wood from 2 years ago that has been covered and in my hands....mostly doug fir....
1. i have a bunch of maple for next year but hardwood will last longer but not put out more heat or is that wrong?
2. draft control...i start a fire, let it run for awhile with the draft full open....hampton says to keep the draft 1/2 open with the blower on....i have been running with the draft full open and the blower on....does it help to close the draft halfway once it really gets going?

thanks!

 

[Corey]

It's easiest to try and keep 'heat' and 'temperature' separate. Essentially any wood, even cardboard or newspaper could get your stove to any given temperature - provided you're willing to stoke enough. But the duration of the heat output basically comes down to pounds of wood burned per given time...burning a pound of wood gives off ~7600 btu of heat regardless of what species it is. So if you have two logs of the same size, but one weighs 5 pounds and the other weighs 10, expect the heavier log to put out heat about 2x as long.

The flip side of the coin is depending on the species, there may not be a lot of difference between the woods you mention. IE Doug Fir= 18.1 Mbtu/cord and Red Maple = 18.7Mbtu. Almost the same btu and almost the same weight (use link in my sig to compare various species) But if you get into say White Fir and Sugar Maple, the difference will be more pronounced.

As for the draft, it takes some experimentation. Just like a gas engine, the stove will operate poorly if there is too little OR too much air. You will probably find a 'sweet spot' on the damper that gives max heat output with minimal wood consumption. Opening up the damper may actually cool the stove off due to the excess air flowing through.

 

[begreen]

welcome clearblue. Doug Fir has a lot of btus, just about the same as our local big leaf (soft) maple. But doug fir also has a lot of oils that combust readily. By leaving the air open you are actually cooling down the fire and burning less clean. Soft maple won't put out much more heat but will often burn longer.

Try this: Get the fire to the point where the wood is fully aflame, then close the air down, 25% at a time. Wait 5 minutes and then another 25%. Depending on the fuel, the flue and draft, you may be able to close it all the way or maybe down to just 25% open. As you close the air control down, watch the fire. You should see a fountain of blue/orange flames start to spout from the secondary manifold pipes. The stove temp should go up, perhaps dramatically. Do you have a thermometer on the stove? That will give you another indication of how well the wood is burning.

Back to the wood. It's possible that the fir will need to have the air control closed more than for the maple because of its high oil content. You want to close it down until the secondary combustion flames start to get a bit lazy and waft ghost-like. That is where you will probably see the most heat from the wood.

 

[clearblue16]

thanks for the good info! this is more complex than i thought but very cool!

 

[begreen]

Enjoy the stove. The next couple days will be cool enough to experiment a bit and let it put out some serious heat.

PS: We love it when folks post pictures of their stoves. If it's burning, you get bonus points.