Question for EPA stove owners ??

[Whitespider]

I’m learnin’ as I go here…
The combustion air entered under cast iron grates in my old furnace, which allowed the fuel load to burn completely in just 10-12 hours. What I mean is… if I started a fire on a cool morning, didn’t add any more fuel to it all day, and then wanted a fire that evening, there wouldn’t be any coals… the firebox would be stone cold. During times of cool nights and warm(ish) days I’d be starting a fire from scratch twice a day.

This Pacific Energy stove (that I converted to a furnace) doesn’t have grates… the fire is built directly on top of the firebrick. With the cool(ish) weather we’ve had this past week I’ve been using it a bit in the mornings… and even after 24-hours I’ll still have enough hot coals to get a fire goin’. I suppose when it’s cold enough to have the fire is burning strong 24/7 it won’t matter… but it seems like I’m losing some efficiency because I’m not really getting any “heat” from the last of the coaling. Even 24 hours after a fire the flue pipe will still be warmish to the touch, and I find coals buried in the ash. The old furnace allowed ash to fall away from the coals, and the air coming from underneath kept those heating … even a pretty small pile of coals would produce heat.

So I’m doing something wrong?
Should I be doing something different?
Or is that just the nature of the beast?

 

[Toxic2]

I have both types of stoves and my EPA does the same thing. I dont mind it tho and i like building fires directly on the fire bricks( Both my stoves are set up like that). I use the monster in the basement that isnt EPA quite a bit and i hate when i let it go too long and lose all the coals..I just plain don't like starting a fire from scratch when i get home from work and its -30 C out..The other extreme is when i am buring nothing but good hard wood in either stove for a couple days or when it is really cold out, i get a huge bed of coals..I solve this by buring soft wood on top of it.. Nice hot flame, fine ashes, no coals and Lots O Heat..

I am sure they are better answers/solution to your issue. This is just my own observation from experience....

 

[Streblerm]

I'm pretty new to EPA stove ownership but I'll take a crack at this. First, I don't think you're losing anything over the second 12hr period. In the old stove it wouldn't be producing any heat over that time so you haven't really lost anything.

With my old stove 4-6hr burns were about the best I could do and I was lucky to have any coals left after 8-10. With the new stove I can have heat for 10-12hrs and have coals for another 12 much like you. The air comes into my stove in the front center right under the door. After a long burn when there are still a lot of coals left I will rake the coals into a pile right in front of the air intake and open up the intake damper This keeps the stove at temp for a while longer and all the coals burn down to a nice fine ash with almost no clinkers.

Even if I don't rake the coals into a pile I find that most everything burns down to a fine ash but I can get quite a bit of heat out of a pile of coals and the intake air wide open. So far I am getting much more heat out of less wood and I have much more control over the draft.

 

[dave_dj1]

My outside hot air wood furnace does the same thing, I find that I have to rake it around a bit to get the hot coals uncovered to produce heat or get the next batch of wood started.
I have never had a stove where you just set it and forget it.
I always thought the stoves with grates couldn't hold a fire as long as a non-grated stove. (I've had the grates in the past) I like to "bank" my fire, especially at night.

 

[laynes69]

Two different animals, it's the nature of the beast. We seen a more even heat, longer burns and less wood used. Typical for most EPA users. I wouldn't see the coals as lost heat or efficiency. Makes the shoulder season much easier to handle. We get better heat now from coals, but that's due to the secondary heat exchanger. A longer path to extract more heat. It took a while to get use to the firebrick floor, wouldn't have it any other way.

 

[Chris-PA]

With your old stove the coals were over the grate so they had airflow and burned up - the heat they released went up the flue and some into the house.and they were gone. With the new stove they're buried in the ashes and cut off from oxygen and last a lot longer. They're not much use for producing heat at that point, but they're dandy for kindling a new fire. Ancient people transported their fire in many similar ways because starting fires from scratch has always been a PITA.

So in short, I think you're looking at it wrong - those tail end coals are not going to put out enough heat to be useful in that respect, so efficiency doesn't really come into it. It's simply a matter of how long they last for their usefulness in rekindling a fire.

During the burn is another story. When I first started burning a fireplace I used one of those pretty fireplace grates. It help the wood up and let the air flow through - the wood burned hot and fast and the coals burned up. Once I got rid of the grate and let some ash build up the coals lasted a long time and the fireplace put out actually put out much more heat.

 

[stihly dan]

This is why people where telling you not to put fan senser in the flue. The new stoves have more heat in them with a lower flue temp. My stove can be 225 deg with 100 deg flue temp. Rake the coals to the front, load the wood to the back. The coals will get real hot and as they burn down the wood then catches to continue the heat cycle.

 

[timbrjackrussel]

Check out the last and maybe the first video on EPA stoves on woodheat .org
I have run a Pacific Energy Summit and a PE Vista. These videos may help you understand how these stoves are to be run. Not realy meant to be fired hard and continuously, coals will build up if you do this.
Wood Heat Videos

 

[myzamboni]

You're doing fine. Remember, you are coming out ahead because you are burning les wood. You also are coming out ahead because you are burning cleaner:msp_smile:

 

[Whitespider]

This is why people where telling you not to put fan senser in the flue. The new stoves have more heat in them with a lower flue temp. My stove can be 225 deg with 100 deg flue temp. Rake the coals to the front, load the wood to the back.

I didn’t put the blower sensor in the flue, I put it in a box mounted on the flue less than a foot above the firebox top. That has actually been working perfectly… when the blower stops running I can lay my hand on the flue pipe (it’s warm yet), and I can put my hand inside the plenum and touch the firebox wall, it’s not as warm as the flue. And, the blower starts and stops only once per burn cycle, which is what I wanted it to do. Maybe I’m missing something, but I don’t see how it would be possible for the flue temperature (a few inches above the firebox) to be over 100[sup]o[/sup] lower than the firebox temperature… that goes against all the principles of thermal dynamics. Either way, the idea is to have the blower auto-start when there’s a fire burning, and have it auto-stop when the fire goes out… and that’s exactly what I’ve accomplished. Remember that this isn’t a full-fledged auto-furnace in the sense that it doesn’t have forced air intake and auto dampers, it can’t sit at smoldering idle waiting for a heat demand command from a thermostat…

Back to the topic at hand I can see the advantage of a long-lasting coal bed, especially during the transitional weather when a fella’ only needs that evening or morning fire, just stir up the coals and toss in the wood… NICE! But I can’t rake the coals to the front and load wood to the rear, this firebox is deeper than it’s wide… it loads with the butt ends facing the door. I haven’t noticed a “longer” burn using this EPA firebox; really it burns about the same length of time as the old dragon did, but does so using less wood. The firebox is smaller and I can only load about 1/2 to 2/3’s as much in it… and heat output (air temperature at the ducts) seems warmer during the peak of the burn.

I was hoping for a longer burn, higher temps and less wood usage… that’s why I asked about the coals. I was probably expecting too much, but I’m not disappointed; if I can get the same burn times and a bit more heat using less wood… well, how can I complain? Besides, I haven’t used it enough to know anything for sure yet; it takes a while to “learn” a new wood burner… I may still get longer burn times when I catch on to all of its little secrets.

Burning cleaner? Well the old brick chimney runs through the center of the house and the flue pipe is a short run… I haven’t “cleaned” the chimney in 18 years, been no need ‘cause it stays clean. But it is amazing to step outside and see nothing but heat waves exiting the chimney.

 

[Chris-PA]

I don't really rake the coals much, just run a poker down through them to knock the ash off them and expose them to the air.

 

[ft. churchill]

Remember that any wood has an intrinsic btu value. That value doesn't change whether burned in a old pot belly or a new epa stove. Our old 1976 homemade air tight stove seemed to have longer burn times, but we love our new Kuma stove. It uses so little wood to heat our home. It's also funny not having a flue damper but it works fantastic.