I'm just gonna ask

kmachn said:

I find myself lurking on hearth.com more and more each week, looking for answers for the hundreds of questions that pop into my head. I've reached the point where I'm just going to start asking the experts, all of you...

I've read a TON of posts on burn times on this forum. My wife and I work full time with 4 small children (5 years, 4 years, 2 years and 7 months) so I'm trying to get the best burn time out of my Cumberland Gap. I know the manufacturer overstates the burn times (I think 15 hours is grossly overstated in this case) but I am only semi-satisfied with with ~7 hours of burn time I'm getting. I'd like to stretch it to about 8-10 with more coals at the end...more coals at 8 hours would make me plenty happy. I installed a flue thermometer this year and it has helped serve as a good guide. I'd like to add a stove-top thermometer, but there is a 1/2-inch gap between the firebox top and the cast-iron top on my stove. With my IR gun, the cast iron top definitely seems to take longer to heat up. In fact, I think I may have overfired a bit last year waiting for it to get to 450-500 and quite frankly still wasn't getting good burn times, probably because of too much combustion initially. So, here are my questions (at least on this topic)

1) Should I remove the cast iron top and just place a thermometer directly on the steel firebox top? Would this be a more accurate measure? I looked at pics of the Isle Royale (since it's in the same Quad family and it's a popular stove on this forum) but it doesn't seem to have the same spacing. This gap is definitely vented, probably intentionally for some reason? I am not intimate with that stove but.... I would advise against such a drastic alteration. The gap is designed, I am guessing here, as a convection channel, as the air in the channel heats up, it rises and pulls cooler air into it, lather, rinse, repeate. Making a change will alter the way the stove is designed to work.

2) I'm wondering if maybe I am getting too much outgassing once the fire gets going, which may be why my times are not as long as I would like. I tried the "cigar burn" method that I read in other posts. It seems to work sometimes, but those flames go where they want and sometimes start catching all of it. One of the major factors to longer burn times is wood species. For example if I burn White Pine I can count on reloading in 4-5 hours, if I burn White Oak, I can easily get 8-10 hours with enough coals on reload. What type of wood are you burning?

3) I don't think it's the problem, but it could be a slight problem with strong draft. I have 23 ft of class A chimney pipe, with 2 offsets/returns. I think all 30-degrees. The stove pipe also has 2-45's. Once I get it good and hot and nice secondaries, I can close it all the way down and usually still get decent flames from the bottom of the firebox. Not sure if this should be happening, or only getting the "dancing flames" at the top. A flue damper may help with your situation here. They are not that expensive and may be well worth it for you. I have one, don't need it, but like to have it as insurance if the stove gets out of hand. A damper will slow your burn and limit the oxygen to the fire. By using one you MAY be able to extend your burns and not send so much heat up and out.


4) At what flue temp should I start shutting down the primary? It's my first year with the stove pipe thermometer (Condar) so I'm still experimenting with what works best. What flue temps should I expect for cruising? This is depends on your set up. I can speak to how I do it..... Open wide untill wood is charred pretty nicely, internal flue temps hit 600 then I cut her back 25-50 % depending on look of fire, stove temps start rising nicely, about 10 minutes later, flue temps usually near 800, I cut her back another 25-30 %, another 10 minutes, she is either closed completely, or just a smidge open, and by a smidge I mean a smidge. Depending on fuel being used, I am now cruising for quite a while..... maybe 8-10 hours (Oak) maybe 4-6 (Pine) or somewhere in between.


5) Am I expecting too much from a 2.4 cu. ft. firebox? Are my expectations unrealistic? I'm not expecting to get the advertised 15 hour burn times (good because they are never accurate IMHO), just hoping to make it manageable enough that after I get home from work (let's say 8-10 hours, minimum) I still have decent enough coals that I can easily reload and not have to overly-combust the new wood and lose a bunch of "mass" to get stove up to temp. I am not familiar with the stove so I will not say one way or the other.

Click to expand...

Long burns really depend on stove, stove size, setup, and fuel. We know the stove and the setup but not the fuel. So..... are you burning Oak, or Silver Maple ? It makes a big difference.

Thanks for calling me an expert, but I can really only address items 3 and 5.

For 3, I think most setups allow the primary air to be turned down all the way and pretty much eliminate flame from the bottom, leaving only the wispy blue secondary flame you mention. However, I also find that in my stove if I turn the primary air all the way down my secondaries soon peter out. This varies, but most of the time I don't use the lowest primary setting, so the question of how the lowest setting works would be just an academic discussion.

For 5, I think you're doing pretty well getting 8 to 10 hours out of a 2.4 cubic ft firebox.

Being a fellow Gap owner I think your doing fine with the fuel you have.I can have a 8-10 hour burn with a full load of oak or osage that have been seasoned for years.Do you have the blower?We burned the first 6 month's without one and the stove did good.found a deal on the blower and the stove kicks alot more heat out.

I don't own a Gap, but I thought I would chime in anyway - how about putting that magnetic stovetop thermometer on the face of the stove in the upper left or right corner. While it may not read as hot as on top of the stove, it would still give you a repeatable, reliable temp to go by and know how hot the stove is running. With a little experimentation of having that top plat off, using it to get a stovetop temp, and then moving it to the face you could fairly extrapolate your temps.

I also think that as you gain more experience with your wood i.d. and scrounging, seasoning, and such that you'll come across better fuel. If you can get a year or two ahead, that's when the benefits of seasoning really kick in. No doubt youve seen many posts here from the long timers who are always pretty far ahead with their wood.

To be fair it sounds like you are doing well for where you are with your fuel. I've always had cherry burn nicely for me, but I can't say I think of it as a fuel with a long burn time, and most of the cherry I've had over the years is always going to ash as opposed
to leaving nice glowing coals at the end of the burn cycle. Oak is always great stuff provided it has been CSS for long enough. Sure it will burn before two years, but the real benefit of oak only comes out after enough time in the woodpile.

Keep learning and experimenting and don't get too frustrated. It's all part of the learning curve, and getting there is half the fun.

No oak,I think there is sufficient combustion air in this 1949 house.I do have an ir thermometer that I check with occasionally but mostly just eyeball.My draft is not the best(13' vertical 16' total) so that may slow my burn down.Like I said the stove did good without the blower but it cranks with it.

Hi Kmachn. Just thought I would throw my latest experiences in. I have the Quadrafire Yosemite which is the little brother to the Gap, but with only a 1.5 cu. fireobox. I know what you mean about not being able to go by your stovetop thermometer. I've ran mine without the top on it and had steady temps of 600 to 625 which is about what your experiencing. With the top on, it is about 200 to 250 less and even lower when I stuck it on the front left corner.

My house is only 900 square ft. and built in 1952. I don't have my outside air hooked up and figure I don't really need it. I do have a Magnaflex Insulflex 6" liner in my old masonary chimney, 17 ft. length total, which I just installed this past summer with a block off plate which really made a difference in stove performance. My draft is good. I'm in the process of getting ahead on my wood supply a few years. What I've mostly been burning is red maple, willow and some locust which is just about a year seasoned out. I've bought a moisture meter but haven't tried it out yet.

I have been getting some good burn times the past few weeks. I've been working some 12 hour shifts and have still been having enough coals to get going when I get home without kindling. Not that my house isn't down to 67 or 68 degrees but the stove is still putting off some heat and is easily revived.

Something you didn't mention that you might want to try is let your ash pan fill up as well as the grate in the floor of the firebox. I tightned my ash pan latch some and just leave it shut, "per tips from this forum". This seems to help me a fair amount on burn times. Try leaving a fair amount of ashes in your stove as a practice.

Here's my routine when getting home from work. I first open the door out wide to cool for a few minutes while getting paper towels and bowl of water to clean the glass, with the help of the ash of course. At this time the coals start to revive. After cleaning the glass, I take a small whisk broom and sweep the ashes back from the front of the stove a bit, then take my metal dustpan and scoop up a pretty good scoop, shake it off some. Carefully carry it out to the bucket outside so I don't get a dust storm from dumping inside. I come back in and turn the dust pan over and rake the remaining coals and ash to the front, put about 3 splits in north to south and a few bigger pieces on top east to west. Then open up the startup air and primary air wideopen and leave the door cracked. Usually by the time I go in the kitchen and grab a drink and a snack it's started up and going again.

I'm not a pro by any means and have learned a bunch from lurking on this forum. Kudos guys!! ;-) I'm for sure a noob to the epa stove scene. I have burned the old Fisher smoke dragons for years and loved them but I now know there is a better and much cleaner way to go about it. The next wood you end up having may give you entirely different results which many times ends up being the culprit. You might dollar bill test both of your doors and tighten up the latches by swaping the washers around if needed.

I usually end up getting up once through the night to feed my stove after going to bed, when getting up to hit the bathroom. Wouldn't have to but more times then not I do. Which probably helps me get a longer burn throughout the next day. I do feel that keeping a fair amount of ashes in your stove helps as far as holding coals. They have a place to snugle up and stay alive. Sorry for the lengthy post. Hey, I'm liking my Quad. Hoping to get a new camera for Christmas. I'll post some pics later on. Your rig looks good. I like those vids. Stay warm!! :coolsmile:

I think the key to long burn times is related to several things. Type/size of split is crucial. Some cut their length to short. If you have room for a 20 inch split, you should cut a 20 inch split, IF you want long burn time. If you have six or seven 16 inch splits in a 20 inch firebox, you're effectively losing an entire split, or split and a half in the load.

The hardwood species listed on a btu chart are best, the oak, locust, hickory, and several other woods.

And one thing I always do is take a big old split or round and put it in the back of my oslo, then shove the other stuff in tight, putting as much in as I can, including little 2 inch rounds on top if space allows.

And of course, not shutting down the air soon enough will burn off the load quicker.

I'd disconnect that OAK if I were you just to experiment, maybe that's putting too much air into the firebox and burning the load off too quickly.

I don't have your stove, so I have nothing to judge the flames by, whether they are too much at one hour into the burn. It was just a thought to disconnect the outside air and see what happens. It may slow down the burn some.

Like e.a. says,the ash pan on most stoves are over rated.I used one on another stove for 2 months and haven't used one since.It may not be the cause of short burns but you can eliminate that area(as far as air leaks) by letting it fill and just shoveling the ashes out.Glad to here you made it through work on one load.