Blaze King Ashford 25 Insert - Poor Burn Time - What am I doing wrong?

[crstrode]

I just thought I would comment on my own thread and see if I could get additional help rather than setting up a new thread on my poor burn time with my new Blaze King Ashford Insert.

I had this vision of loading my wood stove and, walking away and so far my experience has been the opposite. Im trying to rule out issues that may be the culprit, and this may still just be human error and burning subpar small firewood, but if I could just get a 10 hr burn, I would be ecstatic! My longest burn time was 6-7 hrs. (down to coals) I have tried stuffing it with a lot of wood, (Its a mix of Ash, Cherry, Cedar and Hickory I believe) I dropped $7k last spring on this unit with installation, and I want to better understand why its not performing to my expectations. I want to rule out the firewood variable first. How do you do this? Can i just load it up with kiln dried 2x4s? I don't want to overfire!

Previously stated that MC was anywhere between 9-15% but those pieces were on the small size. I have moved on to 18"-22" pieces, and found some MC around 20%-22%. (Don't know how big a deal that is, but I usually set them aside, only burn under 20%) Because you can really only fit 2-3 of these bigger splits E-W, I've taken some large pieces and cut them on the chop saw so I could insert them N-S. Even, when I think Im loading it up to the gills, it seems like in an hour everything has settled down and there's a lot of space left.

There are couple of things I am noticing, that I just want to list here. Maybe someone can help me dial it in.

1. I notice that within a couple hours of starting the stove, the CAT thermometer drops significantly, and eventually almost out of the red and this has me increasing the airflow slightly to keep it in the red. Does this indicate too strong of a draft? or subpar Firewood? I was hoping it would stay in the active range for the whole burn time.
   
   
2. I can't seem to close the air off completely - every time I do this, it seems the CAT stalls. My process so far has been - Once I have the fire going, latch the door and wait for CAT to be in active range. As soon as its in the RED, closing the bypass and I have been waiting about 10 min so that all the pieces catch (or most) and then I dial down to the half position and then another 10 min further to about 12/1 o'clock, On cold day, the house doesn't seem to get past 66 on a mild day the house is 70. Id like it to be 70 every day all day
   
   
3. Should I be using the Blower? It seems every time I use it, while it helps to push out heat into the room, it seems like it has a direct effect on the CAT and causes it to drop in temp. During a mild temperature day, I left the blower off and the stove seemed to perform better, heating the downstairs to 72. I have since not been able to replicate this. Im guessing outside temp is the reason.

I know I am not going to see the same benchmarks as a freestanding stove, and a lot of other factors might play into this (home insulation being one) Im feeling frustrated and want to better understand if there is an installation issue or if this is just subpar wood that isn't allowing me to get the avg burn time. I've burned about a 1/2 cord since Nov and at this rate, I will probably run out of wood by February.

I appreciate any guidance or help, I have added some details to my signature if it helps. Cheers!

I'm on the second season witha BK Sirocco insert - essentially a less adorned twin of the Ashford insert.

I'm guessing that your wood may be a little high in moisture content, and you may be expecting too much in terms of how big a house this appliance can heat. I posted some opinions on my results here:

Trouble with Blaze King

It is an interior chimney, in the center of my house (L-shaped bungalow, 1500sqft, built in 1974). I don't believe there was any block of plate installed, just a liner. Would you recommend a block plate? Absolutely a block off plate will increase the heat being delivered to the house quite a...

www.hearth.com

 

[stoveliker]

I just thought I would comment on my own thread and see if I could get additional help rather than setting up a new thread on my poor burn time with my new Blaze King Ashford Insert.

I had this vision of loading my wood stove and, walking away and so far my experience has been the opposite. Im trying to rule out issues that may be the culprit, and this may still just be human error and burning subpar small firewood, but if I could just get a 10 hr burn, I would be ecstatic! My longest burn time was 6-7 hrs. (down to coals) I have tried stuffing it with a lot of wood, (Its a mix of Ash, Cherry, Cedar and Hickory I believe) I dropped $7k last spring on this unit with installation, and I want to better understand why its not performing to my expectations. I want to rule out the firewood variable first. How do you do this? Can i just load it up with kiln dried 2x4s? I don't want to overfire!

Previously stated that MC was anywhere between 9-15% but those pieces were on the small size. I have moved on to 18"-22" pieces, and found some MC around 20%-22%. (Don't know how big a deal that is, but I usually set them aside, only burn under 20%) Because you can really only fit 2-3 of these bigger splits E-W, I've taken some large pieces and cut them on the chop saw so I could insert them N-S. Even, when I think Im loading it up to the gills, it seems like in an hour everything has settled down and there's a lot of space left.

There are couple of things I am noticing, that I just want to list here. Maybe someone can help me dial it in.

1. I notice that within a couple hours of starting the stove, the CAT thermometer drops significantly, and eventually almost out of the red and this has me increasing the airflow slightly to keep it in the red. Does this indicate too strong of a draft? or subpar Firewood? I was hoping it would stay in the active range for the whole burn time.
   
   
2. I can't seem to close the air off completely - every time I do this, it seems the CAT stalls. My process so far has been - Once I have the fire going, latch the door and wait for CAT to be in active range. As soon as its in the RED, closing the bypass and I have been waiting about 10 min so that all the pieces catch (or most) and then I dial down to the half position and then another 10 min further to about 12/1 o'clock, On cold day, the house doesn't seem to get past 66 on a mild day the house is 70. Id like it to be 70 every day all day
   
   
3. Should I be using the Blower? It seems every time I use it, while it helps to push out heat into the room, it seems like it has a direct effect on the CAT and causes it to drop in temp. During a mild temperature day, I left the blower off and the stove seemed to perform better, heating the downstairs to 72. I have since not been able to replicate this. Im guessing outside temp is the reason.

I know I am not going to see the same benchmarks as a freestanding stove, and a lot of other factors might play into this (home insulation being one) Im feeling frustrated and want to better understand if there is an installation issue or if this is just subpar wood that isn't allowing me to get the avg burn time. I've burned about a 1/2 cord since Nov and at this rate, I will probably run out of wood by February.

I appreciate any guidance or help, I have added some details to my signature if it helps. Cheers!

I can't answer all, but if you are at 66 F inside and want it warmer, your thermostat should be higher than 12 or 1 oclock... Going to the lowest setting (longest burn time) necessarily decreases the heat output.

If your cat stalls, you may have insufficient draft ("pull") to get enough air in through the small hole in the (closed) flapper.

And yes, 20-22% is a bit too high for good performance.

 

[begreen]

I last week ran a cubic foot of 2x4s at 7% or so. It works well, and the burn time was similar to the same weight of other wood, there was no exceedingly hot fire. And this is with a likely high draft from my tall chimney.
My data beg to differ on your opinion here.

I see you say "can be a problem" - that may be correct. It is, however, not always a problem (see my data).

Location and outside temps will figure in. That's why I said "can". Others have noted the same issue with too dry wood.

 

[Diabel]

Pics 1 & 3, at which point (time wise) of the burn were they taken?

 

[Poindexter]

Someone here in another thread, i think it was @begreen , calculated 10k BTU per hour as roughly equal to 3000 watts of electric heat. Two hair dryers on full blast will consume 3000 watts, but partly with the blower motors.

Here is what I would do if all y'all crazy people run a confidential go fund me and buy me a Boxer 24 for Christmas. I would go to my local home store and buy a couple 4x6 planks made out of Douglas Fir with an "sGRN" mill mark to go with the D Fir inside a triangle mill mark. When Doug Fir is surfaced green it is first kilned down to 19.999% MC (wet basis) and then surfaced. The WWPA uses 19% dry basis to qualify for sGRN, my consumer grade moisture meter reads wet basis. Then I would take my bevel gauge to the inside of the firebox, tighten the nut, and then carry my bevel gauge to my chop saw. You see where I am going with this?

It comes down to weight. Wood, regardless of species, has a fairly consistent number of BTUs per pound. However many pounds you can load in the box gives you a certain number of BTUs in the fresh load. The faster you take BTUs out of the stove, the sooner you are down to coals.

I personally cannot fathom 2600 sqft in Philadelphia from here. I have no idea what your heating needs are. I am at 63, almost 64 degrees north latitude, you are at 39, perhaps 40 degrees north. I know my insulation envelope pretty well, I don't know yours at all.

I do have the NELMA standard grading rules, the North East Lumber Manufacturers Association spiral bound noteboook about what is coming out of saw mills near you in Philadelphia. According to the NELMA guide, Lumber is 19% or less. When grade stamped the item will be marked sDRY or it may be marked "KD" kiln dried. Air dried lumber may not be stamped KD. Chapter 4, paragraph 1, copyright 2021.

Also 2021 NELMA, chapter 4, paragraph 2, when marked MC-15 or KD-15, the lumber shall have a moisture content of 15% or less. So there you go. If it is marked sGRN and was milled in the northeast it will be between 15 and 19% MC. If a board or plank is under 15% MC the mill can sell it for more money with an MC15 or KD15 stamp on it, compared to selling it with an sGRN mark.

So any of the Northeastern Species you can find with an 'sDRY' stamp are likely very close to 19% MC. The KD stuff, at least that gets shipped up here, is more in the 6-8% range.

I don't know if you can find Southern Yellow Pine in homestores in the Philadelphia area. That would be in the SEMA grading book (South Eastern lumber Manufacturers Association), except there are multiple Associations with their finger in the SYP pie. If you can find SYP in 4x6 nominal at your local homestore, take a pic of the grade stamp and I will be delighted to track it down. SYP is good stuff. Too expensive for firewood, but it has a fair bit of sap in it and is fairly heavy even dried, as softwoods go.

Do you have any data on how much natural gas you (or the house) were using before the wood burner went in? I have burnt two cords already this season since August. How many daughters do you have at home? I remain stunned by the amount of hot water a teenage female can consume, my youngest is now 28.

 

[esguardian]

I can't answer all, but if you are at 66 F inside and want it warmer, your thermostat should be higher than 12 or 1 oclock... Going to the lowest setting (longest burn time) necessarily decreases the heat output.

If your cat stalls, you may have insufficient draft ("pull") to get enough air in through the small hole in the (closed) flapper.

And yes, 20-22% is a bit too high for good performance.

Yes I understand I have to bring the thermostat up for warmer temps in the house guess I just assumed the stove at this low temp setting would be able to provide the heat considering it’s overall heat output specs…It’s also the exterior wall and perhaps adding some roxul behind the unit and above could help.

I always thought with a tall chimney that produced sufficient draft, how is draft affected when you close off the air. Guess I’m not understanding how the air control and the draft are connected

 

[stoveliker]

Yes I understand I have to bring the thermostat up for warmer temps in the house guess I just assumed the stove at this low temp setting would be able to provide the heat considering it’s overall heat output specs…It’s also the exterior wall and perhaps adding some roxul behind the unit and above could help.

I always thought with a tall chimney that produced sufficient draft, how is draft affected when you close off the air. Guess I’m not understanding how the air control and the draft are connected

Draft is the suction your chimney creates. If you close of the air inlet on your stove, there may not be enough air inlet to get sucked in there. I.e. draft, as in airflow, only is there when air can flow into your stove.

In this case, a small hole remains with the air closed. The design to satisfy EPA requirements is such that you shouldn't be able to close it so much that your chimney is "sucking a vacuum" rather than getting air through. It might be worth seeing if you can check the air flapper; is it blocked, is the hole in it open?

(Yes a tall chimney is likely to produce sufficient draft - I see now in your sigblock on my laptop you've 22', likely straight up, insulated - that should be good).

 

[mellow]

See this post about finding leaks in the stove and fixing it: https://www.hearth.com/talk/threads/blaze-king-sirocco-25-insert.157802/post-2339917

I was getting 14-15 hour burn times with Oak loaded up: https://www.hearth.com/talk/threads/blaze-king-sirocco-25-insert.157802/post-2133483

 

[rdust]

I'm guessing that your wood may be a little high in moisture content, and you may be expecting too much in terms of how big a house this appliance can heat.

20%ish is fine, I’ve never noticed a big gain below that. I agree, 2600sq’ is a big ask for an insert. I’d expect Supplemental at best.

 

[MissMac]

I agree, 2600sq’ is a big ask for an insert. I’d expect Supplemental at best.

yup - agree

 

[esguardian]

yup - agree

20%ish is fine, I’ve never noticed a big gain below that. I agree, 2600sq’ is a big ask for an insert. I’d expect Supplemental at best.

2600 is total sq ft of home. I would not expect to heat the entire home but when you can barely heat the 1400 sq ft downstairs…you start the question things!

 

[crstrode]

2600 is total sq ft of home. I would not expect to heat the entire home but when you can barely heat the 1400 sq ft downstairs…you start the question things!

Blaze King rates that insert as having the capacity to heat 400 to 1600 square feet.

Follow BK operating instructions (all of them) to the letter and you'll have the best results.

 

[singed]

@esguardian I'll mention that different species have different Btu ratings--and ash content. @mellow alluded to it by mentioning burning Oak. I'll say that my feeling is that "all hardwoods burn at the same rate under the same conditions, but give off different amounts of heat."

In our neck of the southern Wisconsin woods, white oak is king. Red oak runs a not-all-that-close second, but hickory and black locust are reliable as well. While drop-dead beautiful, black cherry and black walnut just don't put out the heat and leave behind loads of flyaway ash that have to be dealt with. I recommend you check with your local university ag-school extension and find out what they've measured. Failing that, buy wood with high-Btu-rating at a good price. (I'll attach one I found some while back.)

Here's "my way." I've developed a technique over the 10+ years I've been doing it experimenting with my TRW35 stove, converted to a central furnace. (It is the only heat in our 2400 foot house and serves quite well, but I'd choose a wood "furnace" next time. Because what I installed is still after all only a "stove," although modified to serve as a furnace, and a stove is designed to radiate heat. The basement "furnace room" is by far the toastiest room in the house which turns out to be not a bad motivation for "getting on down there" to get the fire going).

For a cold fire, I use three pieces of kindling for the "floor", running N-S, as you put it. Two long strips of cardboard are placed in the gaps between, with wood shavings or other "tinder" between them. (I used to use crumpled paper, but I found it more tedious than pulling tinder off of split logs.) I used to place slightly larger splits E-W as the second layer as you do, followed by a third layer of the largest pieces, N-S again: a "log cabin." The problem with this is that it is much too loose, and after everything is ignited, the second layer has to be "rotated" ninety degrees to match the N-S orientation of the other layers and consolidate the fire to add more wood.

Now, instead, all the splits go in the same direction, with one exception. I place a single short thin split (which I make up dozens at a time with my indoor 10-ton manual splitter from Harb.Frt), E-W across the front of the first layer. It's thin so the second layer isn't radically tilted up, and will "settle" gently when the strip burns through. I then place more cardboard strips N-S on the thin strip in the areas which will be between the splits of the second layer. The second layer is made up of larger kindling as before, but running N-S with the first layer. The thin strip assures there will be plenty of air flow. The third layer of largest stuff is placed N-S on the second layer and I've learned it doesn't need cardboard and has no trouble igniting when the inferno beneath it gets going. (Incidentally, her royal highness can operate the splitter if needed.)

I pull the baffle forward, out from under the flue at the back, to make the path to the cold chimney as short as possible, and light the fire, keeping the bottom air door and its damper closed. I close the top door partially to keep the smoke contained and to have the draft suck the air through the fire front-to-back. I then shut the top door while opening the bottom one to help the fire work its way up through the wood. I then alternate between top-, bottom-, or both open as the mood strikes me, "influencing" the fire to "move" here or there.

When all surfaces are burning, I close the bottom door and open the top (trying to keep the smoke in) to close the baffle. This point typically takes only two minutes. Now the smoke has to go around the baffle to get to the flue and out giving the heat exchanger more chance to take heat out of the gases. I close the top door and open the bottom for full-on burn. I have forgotten to close the baffle at times, with the result that virtually all of the heat from the fire "went up in smoke." I have also walked away "for just a moment," fully intending to return to close the bottom door, only to remember too-many minutes later and find the chimney temperature in the danger zone. (Her highness now requires I lay the poker on the floor in a certain way to indicate "the baffle is open," and has me carry a hand-held timer EVERY time I step away from the fire. The second is a life-saver.)

With the baffle closed, it takes another 8-12 minutes for the chimney temperature thermometer to reach the top end of the "burn zone." At that point I close the bottom door and set its damper to limit the bottom air; typically I close it 2-1/2 to 3 turns from full open. Top air is set until the flames are "bluish-orange" and "dance." (I see what I see.)

Now as to air draft settings, the TRW35 has a lower, "spinning nut"-style, draft under the fire, and a sliding "top-air" draft above the door with the view glass. The manufacturer of the stove, to this day (I just checked) offers NO guidance in how to set these, other than trial-and-error. As far as I'm concerned, it should have answered the question: "What are they for?" The answers I've imagined for myself, is that the "bottom air" is what determines the "heat" of the fire, and the "top air" is there for "quality burn." The bottom sets the temperature, the top ensures good combustion (unburned gas/smoke is burned before going up the chimney).

With this, I can get an "overnight burn", say 10p-6a, which I define as "still having sufficient coals to rekindle the fire in the morning without cardboard." I won't claim that the 6a fire is still "heating" anything other than itself, but with the right attention, renewed heat is only minutes away. With the firebox warm, I leave the baffle closed and add wood in the same way as building new. If the coals are plentiful, I don't bother with the crosspiece either: any wood put in will ignite quickly.

I should also mention I'm tending the fire every four hours during the day, to keep the heat up. On 20-below days, it's a struggle to keep up, but we usually don't have more than a week's worth of those.

That's what I do. All the best.

 

[ZKlongisland]

I read through the thread with interest. Do you have any update/solution to achieving the desired long burn time?

 

[esguardian]

I read through the thread with interest. Do you have any update/solution to achieving the desired long burn time?

Other than dry wood and perfecting the insulation variables of home and dealing with outside temps...8 hours is where I am at for a low slow burn. I suspect many stove manufactures "embellish" (probably not the right word) their stove stats they market to the consumer. I should further clarify that I have talked with several people who own this stove both on this forum and Reddit. nobody is coming close to a 25 hour burn time on this wood insert. Might be possible with the freestanding stoves, but then why are they publishing those stats for the BK insert. I could be way off here (and I hope I am) but this is my first year with this stove

 

[stoveliker]

I cannot talk for the insert ("25") but I can talk for the 30 box.
I can get the advertised hours, and so can many folks. I recently had a 32-35 hr burn. I don't often need that little heat (because in such weather I use my minisplit), but I can. Even in my very first try I got 26-27 hrs (of heat output, which for me equates to active cat).

It depends a lot on what you define as burn time, but BK is not embellishing the burn times of their 30 boxes. I would be surprised that would not be the same as the inserts. Same technology, slightly smaller firebox.

If you can only get 8 hrs while running with the thermostat near its minimum, something is wrong

 

[begreen]

I read through the thread with interest. Do you have any update/solution to achieving the desired long burn time?

When the heat loss of the house exceeds the output of the stove the solution is to reduce the heat loss or put in a stove (or stoves) with greater output.

 

[mellow]

You guys see that it is rated for xxx sq ft, true, but that is at max temps. I used it to heat 1200 sq feet with uninsulated walls and it did just fine, I would get 12+ hour burns on low with temps in the upper 30's. Colder than that and my burn times would be affected due to increased btu output having to move the thermostat up.

 

[stoveliker]

sq ft ratings don't amount to much. Insulation, drafting windows/doors, dividing walls, sun exposure, volume/surface ratio (and whatever I am forgetting now), all add to the BTU per sq ft one needs to keep a comfortable temperature.

 

[ZKlongisland]

Other than dry wood and perfecting the insulation variables of home and dealing with outside temps...8 hours is where I am at for a low slow burn. I suspect many stove manufactures "embellish" (probably not the right word) their stove stats they market to the consumer. I should further clarify that I have talked with several people who own this stove both on this forum and Reddit. nobody is coming close to a 25 hour burn time on this wood insert. Might be possible with the freestanding stoves, but then why are they publishing those stats for the BK insert. I could be way off here (and I hope I am) but this is my first year with this stove

I empathize with your frustration with mismatch between your expectation and real life experience. I'm new to wood burning and found following resource, in addition to this forum, to be of help:

A non-commercial service in support of responsible home heating with wood - An Online Wood Heat Booklet

The Wood Heat Organization was formed to support the public in the responsible use of wood energy in the home. We fulfill our mandate by providing reliable information, by conducting research into wood heating-related issues and by representing the public interest in discussions of policies that...

woodheat.org

 

[esguardian]

I cannot talk for the insert ("25") but I can talk for the 30 box.
I can get the advertised hours, and so can many folks. I recently had a 32-35 hr burn. I don't often need that little heat (because in such weather I use my minisplit), but I can. Even in my very first try I got 26-27 hrs (of heat output, which for me equates to active cat).

It depends a lot on what you define as burn time, but BK is not embellishing the burn times of their 30 boxes. I would be surprised that would not be the same as the inserts. Same technology, slightly smaller firebox.

If you can only get 8 hrs while running with the thermostat near its minimum, something is wrong

I had pretty much given up and accepted the 8 hours, now I'm on a rampage again to see what is going on. This morning with temps in the mid-40s I reloaded. Yes, there were coals from the previous day. Do you count coals as part of your burn time? I would think most people would say no, but I'm not exactly clear on that variable. If yes then I got over 12 hours. 7-8 of active heat output on low.

I loaded it up around 7 am, got a substantial burn going, and then dialed the temp down to where the cat glows and you get occasional candle-flicker flames. It's about 2:50 pm now and the firebox has mostly died down to ashy wood, if I opened it up now, I would have to rake around the coals and reload but for the most part, it is about done. The temp has fallen out of the active zone.

Is it possible my factory CAT is faulty or is there something else wrong? I will probably stop burning in the next week or so since temps are rising (and Im almost out of wood) I'll have the unit cleaned in June. What should I have the guys check for?

 

[begreen]

Is it possible my factory CAT is faulty or is there something else wrong? I will probably stop burning in the next week or so since temps are rising (and Im almost out of wood) I'll have the unit cleaned in June. What should I have the guys check for?

That's low, even for some non-cats. Do you see smoke out of the chimney top when burning after the cat is engaged? If so the cat may be bad or the bypass may be leaking.

 

[stoveliker]

I had pretty much given up and accepted the 8 hours, now I'm on a rampage again to see what is going on. This morning with temps in the mid-40s I reloaded. Yes, there were coals from the previous day. Do you count coals as part of your burn time? I would think most people would say no, but I'm not exactly clear on that variable. If yes then I got over 12 hours. 7-8 of active heat output on low.

I loaded it up around 7 am, got a substantial burn going, and then dialed the temp down to where the cat glows and you get occasional candle-flicker flames. It's about 2:50 pm now and the firebox has mostly died down to ashy wood, if I opened it up now, I would have to rake around the coals and reload but for the most part, it is about done. The temp has fallen out of the active zone.

Is it possible my factory CAT is faulty or is there something else wrong? I will probably stop burning in the next week or so since temps are rising (and Im almost out of wood) I'll have the unit cleaned in June. What should I have the guys check for?

No, burn time is "usable heat". Having 3 coals left does not provide that (at least for me - and my stove is in the basement).
My 30+ hrs was "providing sufficient heat to keep the house at 68-70 F. (I think the outside temps started at 26 F or so early morning when I reloaded, rose up to near 40, and maybe went to 35 F overnight).

When I go "low and slow" there are *no flames* anytime (after the initial charring phase). The occasional candle flame suggests that you are burning at a higher heat output. (That may be fine, if that is the heat output level that you need for comfort.) But even with a candle flicker, I'd think 8 hours is on the low end.

If the cat would be faulty, there would not be much heat produced in the cat (and the glowing after dialing down is at least an indication that may not be the case). If the cat does not produce much heat, the Tstat would open up the air more, leading to shorter burn times indeed. But you would also see smoke when burning low (i.e. smoldering and relying on the cat to clear the smoke and with that produce the majority of the heat output).

When you say "ashy wood", is that "black blocks with ash on the outside" or is that ashes?
When my stove is done (cold), I may have 2 crispy black pieces of 3" long, 2" wide and 3/4" thick left in the box, but the rest is essentially a flat layer of ash. Are you having more fuel left than that? (even if not producing gases anymore, leading to a cat that falls out of the active zone) I'll take a pic in a minute and upload it. (My stove just went cold this morning after a partial reload last night.)

What is your flue height (again)? - Edit: I see 22'. Seems a pretty decent height. Could be slightly tall, but I think it should be fine.

Is your home very tight? I'm asking because insufficient draft, exacerbated by colder flue gases when running low, could lead the stove to peter out - despite the Tstat, if you're unlucky.

Edit more: have you done the dollar bill test? (air leaking in would increase the burn rate).

Puzzling indeed. Have you contacted BK? Generally they are very willing to help trouble shoot.
@BKVP?

 

[mellow]

Did you insulate your fireplace? I see you have an exterior chimney which will eat up BTU's.

Check out this thread and then go do the same test before you make any changes: https://www.hearth.com/talk/threads/finally-got-around-to-insulating-my-fireplace.75755/post-1842157

 

[BKVP]

I had pretty much given up and accepted the 8 hours, now I'm on a rampage again to see what is going on. This morning with temps in the mid-40s I reloaded. Yes, there were coals from the previous day. Do you count coals as part of your burn time? I would think most people would say no, but I'm not exactly clear on that variable. If yes then I got over 12 hours. 7-8 of active heat output on low.

I loaded it up around 7 am, got a substantial burn going, and then dialed the temp down to where the cat glows and you get occasional candle-flicker flames. It's about 2:50 pm now and the firebox has mostly died down to ashy wood, if I opened it up now, I would have to rake around the coals and reload but for the most part, it is about done. The temp has fallen out of the active zone.

Is it possible my factory CAT is faulty or is there something else wrong? I will probably stop burning in the next week or so since temps are rising (and Im almost out of wood) I'll have the unit cleaned in June. What should I have the guys check for?

Would you please post an image of a "full load" please?

Thank you
BKVP