Operating an everburn stove

[ControlFreak]

I know that there has been a number of threads discussing everburn, or downflow stoves, but I don't recall seeing anything recent that's specifically directed toward operating the bypass.

I am particularly curious about how you know when it's time to close your bypass and whether you ever have the situation where the combustor doesn't light off. Do you reopen the bypass, or just let it sit? Is the rumble the only way of knowing if the combustor is kicking in?

Once the combustor is lit, and as the fire dies down a bit, do you then just toss in logs on top of coals and close the bypass immediately?

And while your at it, what model stove do you have, and what kind of burn times do you exprience?

Thanks,
Dan

 

[North of 60]

THere is no CAT/Com-buster in the everburn model. A secondary burn chamber? YES. PM (burning is love) He is in tune with operating this creature.

 

[schortie]

I am a few months into operating my Defiant NC - Everburner. The answer to all of your questions is sometimes yes, sometimes no.

I know when to close the damper by general assumption and growing experience. Generally, with a thick coal bed, a full stove running/charring at ~500, I close the damper. Depending on the everburn gods, it will "light off" as you say or not. Sometimes the gods trick me and it 'lights off" then stops, other times nothing at all. More often then not, when it doesn't light off, I open the damper and let the splits char some more - usually when I close the damper again, the everburn kicks in. If not, I have to open the damper again and futz with the orientation of the splits in the stove. Lately I have been waiting longer for the everburn to kick in before I reopen the damper. Sometimes it kicks in after a bit, sometimes not. More patient folks might just close the damper and be done with it, but I just hate to see the amount of smoke coming out of my chimney when it doesn't engage. When the stove has been running strong for a while and we're burning 24/7 all of this rigamarole is lessened, and it runs more smoothly, but those everburn gods are as playful as Puck and keep me on my toes.

I determine if the everburn is engaged by the rumble you've probably read about. Sometimes it's louder than others, but it's definite. There are times when there is no rumble, but I know the everburn is engaged because there's no emissions from the chimney. Usually this is toward the end of the burn cycle.

Burn times have a lot of variables as I'm sure you're aware. I have yet to fully pack all of the 3.4 cu.ft of firebox, but I can have a solid coal bed and ~400* after 8-9 hours with a fairly full load of larger splits. With a similar load, I can keep the stove between 500-650+ for solid 5-6 hours.

Hope this begins to answer your questions.

 

[Slow1]

From my limited experience the keys to getting it to light off seem to be related to having a good coal bed and getting the back of the stove (everburn area) good and hot. Thus I have taken to the habit of making sure that I have some good hot chunk of coal sitting back there near the smoke exit point when I do my reload and rearrange the coals. This seems to help insure that once I get the load up to temp it will light off quickly. If it doesn't light off when I close the damper (I like to get top up to 525 or higher stove top) I will re-open and try again after getting temp a bit higher than last time.

How do I know if it is going well? Beyond heading out to look at the smoke and the rumble, I watch the flue temp to not fall off much after closing the damper. I like to see a steady temp, if temps are falling (both stove top and flue) then I know I did not get ignition and I have to re-open. I'm trying to gather enough data to have solid numbers to use as guides but don't have them in place yet as there are so many variables (draft has such a huge influence it seems and the draft is affected by the temperature outside etc... so it is hard to be definite on this).

 

[dtabor]

I will agree with everything that Schortie said as I have the same unit. There is no consistency. I will ADD to his that I have done everything...coal bed, char, temp up and then close the bypass, hear the rumble, the rumble continues so I think all is right with the world, then check the chimney and there's smoke. I have learned to be one of the less patient people he mentions, I do what Im supposed to on my end, if it does on its end great, if not, oh well, I go on with my day. Just remember to check my chimney more often for buildup.

 

[Northern NH Mike]

I am particularly curious about how you know when it's time to close your bypass

Once the combustor is lit, and as the fire dies down a bit, do you then just toss in logs on top of coals and close the bypass immediately?

And while your at it, what model stove do you have, and what kind of burn times do you exprience?

Been burning for three months with a VC Encore NC, so keep that degree of inexperience in mind. With the right load I can get a reliable 8 hour burn.

I close the bypass when I feel that the splits have a good char and the primary, open all the way, will continue an active burn and not start to smolder. Often my thermometer is approaching 500 at this point.

I also leave the bypass open for a few minutes when reloading to get the temp up again and char the new logs. Tend to rake most of the coals up front, but leave a layer at the back and near the refractory.

The rumble kicks in immediately when I have a thick coal bed. I also find that the colder out it is the faster the everburn starts. We've been -8 to -10 the past few nights.

I'm thinking everburn is as much art as science.

 

[BurningIsLove]

I am particularly curious about how you know when it's time to close your bypass

Once the combustor is lit, and as the fire dies down a bit, do you then just toss in logs on top of coals and close the bypass immediately?

And while your at it, what model stove do you have, and what kind of burn times do you exprience?

Been burning for three months with a VC Encore NC, so keep that degree of inexperience in mind. With the right load I can get a reliable 8 hour burn.

I close the bypass when I feel that the splits have a good char and the primary, open all the way, will continue an active burn and not start to smolder. Often my thermometer is approaching 500 at this point.

I also leave the bypass open for a few minutes when reloading to get the temp up again and char the new logs. Tend to rake most of the coals up front, but leave a layer at the back and near the refractory.

The rumble kicks in immediately when I have a thick coal bed. I also find that the colder out it is the faster the everburn starts. We've been -8 to -10 the past few nights.

I'm thinking everburn is as much art as science.

Yep indeed it is. A few sacrificial chickens laying around dont hurt either. The responses above are a great summation of the many threads on the topic, so not much for me to add, but I'll ramble on anyhow.


You seem to have the general idea...For a brand new fire from a cold start, bypass needs to be open for most people a minimum of an hour to develop draft & coal bed. Then after that, it's all about split orientation & futzing w/ the coals to get optimum movement internal to the throat in the lower rear. As for temps, my normal operating range is about 420-550 on the griddle (500 on average) as measured by a simple, surface magnetic thermometer. I also have a probe thermometer a few inches behind the flu collar thats normally between 1000-1300F. Divide that last number by 2.5 if you have a surface magnetic and a single wall pipe. If you have a rumble and temps above 400, you dont really have to worry about smoldering. You can always check the stack for emission cleanliness to confirm.

Keep in mind that immediately after closing the bypass with a 'newer' fire, it may take up to a minute for the refractory chamber to get up to temp, so even with a rumble, might take 30-60 seconds for the emissions to become completely clear. If you're just reloading an existing fire that was drafting well & successful secondary combustion, then it should be nearly instantaneous once you close the bypass after letting the fresh splits coal up a bit w/ the bypass open as everything should be at operating temp.

Yes, colder outdoor temps will normally produce better drafting conditions. Drafting is essential to successful operation and (lack of draft) is the cause of most stalls, even if you have good splits and coal bed. The orientation of the splits in the firebox will greatly affect the draft. If you jam them in too tight w/o gaps between them, then the stove will draft just fine w/ the bypass open as "up" is the natural direction they'd want to move and they have a huge opening (the bypass) to move out. But once you close the bypass and they have this small exit, those gaps become essential as you want high velocity between them to really heat those leading edges of coaled splits. And you cannot have the throat blocked else that is a non-starter. You *can* block the throat w/ coals, but not w/ a solid split in most cases.

For the large version I have, burn times are 8-12 hours. For the long burns when you're not near the stove (e.g. in bed), the key is timing. You want a healthy coal bed w/ at least 2 well coaled, large burning splits on those coals (maybe 4 for medium splits). Basically, you want to leave enough room at the top of the firebox for 2+ splits filling up the firebox as much as possible. Add the last two splits and DONT let them get coaled. Just put em in, close the door, and close the bypass. There should be plenty of active fuel from the original splits to maintain a hot fire for hours (ensure that you hear a healthy rumble). Over the next few hours, as the splits below them reduce to coals and burn, the fresh splits will have been pre-heated and will ignite on their own. It's like a delayed auto-loader.