The thermometer placed near the bypass - I guess I better try that. Not sure I wanna see! Do you have two thermometers, so you can see stove top temps at the same time as back/side temps?
Harman FireDome Tricks
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I can't tell. Is that 800* on that therm? Ya, I've never checked the side of the stove near the bypass. Guys at Travis last year told me 800* flue probe temp. was too high. Ha ha.
That's why I'm thinking these stoves are made for big hunks of wood once they get hot.
Can you kill the primary air completely jdonna?
That's why I'm thinking these stoves are made for big hunks of wood once they get hot.
Can you kill the primary air completely jdonna?
I have/had 3 therm. on the stove
1. Stove top
2. On the side of the stove near the handle
3. Flue Probe thermometer.
Bear in mind, I have problems with my stove, pending action on. I am curious to see what you guys measure out there.
I had seen temps over 900 degrees with the non-contact thermometer.
That is with as close to limited primary air as you can safely run, if you slowly close it down it will whoosh and have mini back puffs. The primary air also has a small hole drilled in it and the front edge of the slide has a cut away notch.
Killing primary air on the stove still allows unrestricted secondary air coming in at the shoe brick, which upsets the pressure balance of the firebox.
I've done some searching and seen some other threads commenting on this as well with the Vermont Castings NC models.
Contrary to what deductive reasoning you would think that running 600 degree stove top is normal, well it is not the indicator, what the indicator is where the smoke exits the exaughst port on your refractory secondary combustion A very narrow channel opening shooting right at the side (back panel) of the stove creating a hot spot. There should be an internal baffle to spread the heat out over the stove to even the temp. I am guessing there is going to be a lot of gasket issues down the road, but that is my opinion.
1. Stove top
2. On the side of the stove near the handle
3. Flue Probe thermometer.
Bear in mind, I have problems with my stove, pending action on. I am curious to see what you guys measure out there.
I had seen temps over 900 degrees with the non-contact thermometer.
That is with as close to limited primary air as you can safely run, if you slowly close it down it will whoosh and have mini back puffs. The primary air also has a small hole drilled in it and the front edge of the slide has a cut away notch.
Killing primary air on the stove still allows unrestricted secondary air coming in at the shoe brick, which upsets the pressure balance of the firebox.
I've done some searching and seen some other threads commenting on this as well with the Vermont Castings NC models.
Contrary to what deductive reasoning you would think that running 600 degree stove top is normal, well it is not the indicator, what the indicator is where the smoke exits the exaughst port on your refractory secondary combustion A very narrow channel opening shooting right at the side (back panel) of the stove creating a hot spot. There should be an internal baffle to spread the heat out over the stove to even the temp. I am guessing there is going to be a lot of gasket issues down the road, but that is my opinion.
jdonna said:
I often get a minor version of this situation, but only early on from a cold start, when lots of outgassing is occurring with no coal bed. I don't worry too much about a limited amount of whooshing and mini back puffs - I get no smoke in the house, or smoke smell.
Usually I will just re-open the bypass and shut the primary air to zero, then after a few minutes try to re-start the secondary burn with the air back up to half open. Then slowly close the air. Eventually I can always step it down gradually. all the way to zero primary air, as the burn progresses.
As troublesome as your stove may be, it still sounds better than a lot of VC Everburn stories! Any glowing?
I guess 900* is 900*, but do you think they've built the back of these stoves to withstand this kind of heat? I mean, the manuf. has to know these things light up at 1200*.
Jdonna, do you have a fan?
If I didn't have the blower, I think I would have a much harder time controlling stove top temp. Oddly, Travis says to put the therm. over the front loading door, which is the coolest place on the stove. I put it at the back of the stove near the flue collar. I'm usually reading 600-700 when settled in. That's warm for me, and I'm playing around with wood size and loading to get combustion, lower temps., w/o stalling. Most of the flaming inside the box is hitting the back of the stove right there where I put the therm.
Maybe with colder temps I'll be able to close primary air completely. Right now I have to leave it open or I'll stall.
Does anyone throw in a split midway through a burn, like before heading off to bed? I guess that would mean another couple hours of babysitting for jdonna!
These stoves seem more conducive to that than a tuber.
Jdonna, do you have a fan?
If I didn't have the blower, I think I would have a much harder time controlling stove top temp. Oddly, Travis says to put the therm. over the front loading door, which is the coolest place on the stove. I put it at the back of the stove near the flue collar. I'm usually reading 600-700 when settled in. That's warm for me, and I'm playing around with wood size and loading to get combustion, lower temps., w/o stalling. Most of the flaming inside the box is hitting the back of the stove right there where I put the therm.
Maybe with colder temps I'll be able to close primary air completely. Right now I have to leave it open or I'll stall.
Does anyone throw in a split midway through a burn, like before heading off to bed? I guess that would mean another couple hours of babysitting for jdonna!
These stoves seem more conducive to that than a tuber.
Troutchaser said:
I don't have a blower, but a fan on the floor blowing cooler air to the back of the stove and brick hearth (stove sits about a third of the way back in my fireplace). I originally did this as a method of heat transfer to get the house warmer, only later realizing it is a good (essential?) way to keep stove temps down.
Jdonna, don't feel left out, I have those same temps on my stove all of the time. I talked to my dealer about it. He is a very reputable dealer, who I trust to shoot straight. He said that as long as the primary air control is 3/4 open or below and the damper is closed, the stove will not over fire. It is built to take that level of heat. This is reflected in the owner's manual that says not to leave the primary air control set at maximum for days at a time or damage may result.
Overall, it is reasonable to expect that stove temperatures can be higher than what is traditionally considered maximum, especially as different materials allow for more efficient burning. If you told Ben Franklin that some stoves would have a honeycomb of metal coated with specialized precious metals to chemically react with the smoke and wring out more heat from the load of wood, he would not believe it.
On my Oakwood, I try to keep the rear thermometer below 800.
Overall, it is reasonable to expect that stove temperatures can be higher than what is traditionally considered maximum, especially as different materials allow for more efficient burning. If you told Ben Franklin that some stoves would have a honeycomb of metal coated with specialized precious metals to chemically react with the smoke and wring out more heat from the load of wood, he would not believe it.
On my Oakwood, I try to keep the rear thermometer below 800.
Jdonna, I put the thermometer in back, on the opposite side of the bypass damper handle, a few days ago. It can go up to 500-700F within minutes of the afterburner kicking in. (Also amazing how cool it is when you are NOT burning smoke, like 250F.) That's with mostly small fires and low air.
Tonight I have conditions similar to the ones you mentioned: no wind and a 30 degree outside temp. I shut the bypass after 5-10 minutes open with full air on a hot reload, really blazing. With a half-load of very dry medium oak splits, I then left the air open halfway for about 15 minutes, by accident. Normally I would step it down to near zero air by then. Sure enough, I hit 800F in only 15 minutes- wow!
BBarrister, as for the dealer saying "as long as the primary air control is 3/4 open or below and the damper is closed, the stove will not over fire" - I guess we need a definition of overfire we can all agree on. I think the variables of individual situations might prove there are exceptions to that dealer's comment.
Tonight I have conditions similar to the ones you mentioned: no wind and a 30 degree outside temp. I shut the bypass after 5-10 minutes open with full air on a hot reload, really blazing. With a half-load of very dry medium oak splits, I then left the air open halfway for about 15 minutes, by accident. Normally I would step it down to near zero air by then. Sure enough, I hit 800F in only 15 minutes- wow!
BBarrister, as for the dealer saying "as long as the primary air control is 3/4 open or below and the damper is closed, the stove will not over fire" - I guess we need a definition of overfire we can all agree on. I think the variables of individual situations might prove there are exceptions to that dealer's comment.
Pretty easy to duplicate last night's scenario: this morning I loaded a few small oak splits on top of a few that halfway to coals. Full primary air for a few minutes, then shut the bypass and put air at just over 1/3 open.
Temps on the sidewall of the afterburner went from 400F to 800F in eight minutes. That's 50 deg a minute, nearly one degree per second. Shut the air back at 800 (since the thermometer only goes to 850F), turned on the fan and down it went. With air blowing I doubt I can get a true reading, so I guess I'll get an IR gun. One that goes over a thousand, LOL.
Jdonna, I'm starting to think your temps aren't that abnormal. Maybe you need to get the air down to 1 or 2, and get a fan. At least you're babysitting will become more predictable and enjoyable!
Temps on the sidewall of the afterburner went from 400F to 800F in eight minutes. That's 50 deg a minute, nearly one degree per second. Shut the air back at 800 (since the thermometer only goes to 850F), turned on the fan and down it went. With air blowing I doubt I can get a true reading, so I guess I'll get an IR gun. One that goes over a thousand, LOL.
Jdonna, I'm starting to think your temps aren't that abnormal. Maybe you need to get the air down to 1 or 2, and get a fan. At least you're babysitting will become more predictable and enjoyable!
Interesting guys, interesting. Just wait until it is -0 degrees outside. That is my point, what is the agreeable temperature?. Harman needs to come out and say what the defined temperature of that firedome temperature to constitute over-firing. When I asked the question with a normal temperature is by an high level employee of Harman who no longer works there a year ago, it was a shifty answer on what normal is, when I said my temps a lose statement was given that is normal. When I told him the temperatures, he said it should not be that high. IF you have a dark room when it is going through that phase of burning, you can see a faint band of red when you are at 850 degrees. That is defined as over-firing. Point in being there is nothing you can do to slow that temperature down when it gets into that burn zone, if you do choke it down it will whoof. You also rapidly increase your draft when it is up at that temperature as well, further decreasing burn times. My primary air was barely cracked open.
That is a peak and valley heat cycle I must say.
Thanks guys for checking into it as well.
Branch when you use a non-contact thermometer you will get a true accurate reading, which in my case measured a lot higher of a temperature than the rutland magnetic thermometer. If you burner higher moisture content wood it just delays that portion of the high burn firedome rate to a later point of the burn cycle.
One has to wonder what the BTU output is for that half hour to hour of the burn cycle when it is doing that "hyper" burn.
That is a peak and valley heat cycle I must say.
Thanks guys for checking into it as well.
Branch when you use a non-contact thermometer you will get a true accurate reading, which in my case measured a lot higher of a temperature than the rutland magnetic thermometer. If you burner higher moisture content wood it just delays that portion of the high burn firedome rate to a later point of the burn cycle.
One has to wonder what the BTU output is for that half hour to hour of the burn cycle when it is doing that "hyper" burn.
jdonna said:
One thing you could try is opening the bypass (as well as your key damper). It is counterintuitive, because it may increase your stove top temps and/or flue temps. But the guys with cat stoves have pointed out in threads that if the cat is getting too hot, you can open the air or the bypass to feed less smoke to the cat. Of course with our stove you don't want more air, but letting the smoke up the flue will cool the AB chamber in back of the stove instantly.
I wonder if this stove is a slightly better design than VC, just enough to keep peak temps 50-100F cooler than those glowing VC Everburns when they are pushing 1000F. But it is too bad Harman won't acknowledge to you they've made a stove that reaches borderline overfire by design. I hit 825F on the back-side this afternoon without even trying - a small load with less air than usual, and away it went.
If I hadn't already been happily using this stove for two years, I might be concerned. But without knowing how hot it was, I saw no problems (and no glowing - I'll have to look closely now). Now that I know, I am more intrigued than worried. Just the nature of the beast, I guess.
More temp readings from the side wall of the back chamber: last night went from 250F to 800F in 8 minutes at 25% open air (70 deg per min); this morning it pegged at 850F (so was it higher?), up from about 500F in under ten minutes at 50% open air. Hot.
Branch and anyone taking temp measurements...
What is your flue temp when you are measuring 800+ sidewall temps?
On my stove, it would grunt and you could hear the air rushing into the secondary during that phase. On a cold day the heat shield would vibrate.
I had seen it from 600-1200 degrees internal temp probe on single wall chimney. Granted not the most measurement because of radiant heat skewing the reading on the probe, but still.
Do you notice that at those temps it effects your burn times?
What is your flue temp when you are measuring 800+ sidewall temps?
On my stove, it would grunt and you could hear the air rushing into the secondary during that phase. On a cold day the heat shield would vibrate.
I had seen it from 600-1200 degrees internal temp probe on single wall chimney. Granted not the most measurement because of radiant heat skewing the reading on the probe, but still.
Do you notice that at those temps it effects your burn times?
jdonna said:
I wouldn't worry about 1000 degrees internal if only for a short while. The flue temps that concern me are when the bypass is open - I've seen it shoot right up in minutes to near 800F (that's surface, or around 1500F internal?!). I think the flue temp has to be the deciding factor in closing the damper. I try to close it around 500F surface.
Once the bypass is closed, flue may stay around 500-600 surface (around 1000F internal) for a few minutes, then drop for a while as the sidewall temps climb to 800. Eventually the sidewall temps will also drop back down a few hundred degrees also, as the outgassing slows and the air is notched down. (The fan helps lower temps, too.)
Right now the stove has been cruising on good oak for some time with air set almost shut, at two notches: sidewall=650F, stovetop=450F, single-wall pipe=350F external. I think these temps are typical and yes, I think maybe a bit too much heat can be drafted up the flue, and that will shorten burn times.
On the other hand, I grilled a porterhouse and portabella mushrooms inside the thing this afternoon, as well as cooking grilled cheese and a pot of soup on top of it. As Dennis says, life is good.
Hi folks, just back to civilization after a weekend away. I had the same thing this weekend. Cold night, so around 9:00PM I loaded the stove to the gills with dry poplar and set the air control to 3. It already had a good bed of coals and the sidewall temperature was 450. It climed to 675 and held. I thought I would be good there, that's the perfect cruise temp in my opinion. Watched it for an hour, it held steady and went to bed. Woke up around midnight and walked down to check the stove. Sidewall was 850 and in the dark room I could see faint red glow.
I don't mind the heat but that darn smoke smell was back again. Driving me nuts!
I wonder if leaving the air control around 5 as the minimum will help? My theory is the at with more air coming through the primary, there is less air forcing its way through the afterburner raising the temps. I'm going to try that this weekend. (No cool enough yet for 24/7)
I'm with you guys, we need some more direction from Harman.
Edit: I will move a box fan downstairs to move the air off the back during overnight burns. Seems like a good idea.
I don't mind the heat but that darn smoke smell was back again. Driving me nuts!
I wonder if leaving the air control around 5 as the minimum will help? My theory is the at with more air coming through the primary, there is less air forcing its way through the afterburner raising the temps. I'm going to try that this weekend. (No cool enough yet for 24/7)
I'm with you guys, we need some more direction from Harman.
Edit: I will move a box fan downstairs to move the air off the back during overnight burns. Seems like a good idea.
As soon as it cools down again (Thursday night?), I'll engage and check the back of the Leyden for high temps. I've not done that before. Might be interesting to see the differences, if any. The heat radiating off of this stove when in afterburn is incredible though.
About how long do you expect these high temps with a 2/3 full stove? I was thinking the first hour or two and then things would slow way down. BBarrister surprised me when he stated that his temp was 850 back there some three hours later.
So, does Harman not offer a blower with the Oakwood? That would move the heat off the back of that stove.
About how long do you expect these high temps with a 2/3 full stove? I was thinking the first hour or two and then things would slow way down. BBarrister surprised me when he stated that his temp was 850 back there some three hours later.
So, does Harman not offer a blower with the Oakwood? That would move the heat off the back of that stove.
BackwoodsBarrister said:
I think that's possible - if you see more flame in the front firebox, it means less smoke to be burned in the back AB chamber. But then will you have higher flue temps with that much air, and plow through the wood faster?
I should mention: I'm getting these temps with a modified stove (three firebrick added to each side to reduce firebox from 21" to 16") and therefore smaller fires. I will update temps when I de-modify the stove in a few weeks or so.
Three hours seems like a long time to be over 800F, my temps go down long before that. But again, I'm burning smaller loads. It will be interesting to see how different conditions change the temps and their duration.
Hello Folks, long time since I've been around. I have an update on my Oakwood. I had my sweep come out last week to clean the stove and chimney and get ready for the winter. I told him I was still having the smoke smell issue when using the AB. He inspected it very closely and found that the bolts connecting the back half of the stove to the front half were all loose. Most needed three turns to tighten them up, all needed at least a half-turn. His theory is that they either loosened from the heat cycles or were not snugged up properly at the factory. Either way, the gasket was not getting a good seal. Hopefully that will take care of the smoke smell this winter.
The stove checked out very well though. Very little creosote from last winter's burning (2.5 cords) The combustion package is still looking good. I'm ready for another winter with the Oakwood.
The stove checked out very well though. Very little creosote from last winter's burning (2.5 cords) The combustion package is still looking good. I'm ready for another winter with the Oakwood.
BackwoodsBarrister said:
Just wondering, did he pull the combustion package out to clean out any ash? I pulled mine out this summer and it had about two cups of fine ash accumulated in it. Probably would have been fine another season, but I think three seasons and it would be clogging up and performing poorly.
Branch, good hear from you again. He removes all of the firebricks/refractory panels and cleans it from the front, then from the top with the pipe removed. He does not remove the package. Now, that is at my request, as he said he could get 95% of the ash without removing it, since removing it causes a higher chance of it cracking or otherwise falling apart.
There was good bit of fine ash in the bottom of the combustion package but it is cleaned up now. I seem to be having good luck with the once a year cleaning. We will see how it goes this year.
There was good bit of fine ash in the bottom of the combustion package but it is cleaned up now. I seem to be having good luck with the once a year cleaning. We will see how it goes this year.
That's good thinkin' - it gets really fragile after a few years. 95% sounds optimistic to me, but even only getting a good half+ of it each year should be enough.BackwoodsBarrister said:
Happy burning!
Had a guy on here last year fighting with his stove for weeks till he(with help from hearth members) determined he had just about no draft. Hated the stove til he fixed the draft,then he loved it. Those getting poor performance with any EPA stove most likely have weak draft or wet wood,or both.BackwoodsBarrister said:
Donk4kyv
Member
I just did my mid-season chimney clean to-day. Collected a large coffee can about 80% full of soot and creosote. Interesting thing was that most of it had already fallen to the bottom of the flue and fell out into the pan I had placed underneath, the moment I removed the bottom cover. Only about 1/8" build-up on the flue pipe, which is 6" double wall stainless steel, insulated.
I was concerned about creosote build-up because my AB doesn't seem to be working up to par, but the total soot/creosote accumulation doesn't seem much different from previous burning seasons. Next step is to check the CP and shoe brick to see if any of the secondary air passages are stopped up.
My question: has anyone else had difficulty removing the shoe brick? Last year the guy from the store, who installed the stove two years earlier, came to check and clean it. He couldn't get the shoe brick to budge after removing all the other bricks surrounding it, so I don't think he was able to clean it properly. I plan to do my own cleaning from now on, because I suspect he doesn't know the stove very well; he had to borrow my owner's manual to figure out how to re-assemble the bricks, and I didn't like way he was poking inside the CP with the vacuum cleaner hose. The bottom of the shoe brick seems stuck tight to the cast-iron part that supports it. All the other bricks are slightly loose and can be budged, even with all the metal clips in place. I'm wondering if I have missed something in the procedure; I don't want to force anything too much since both the shoe brick and CP are expensive to replace.
The stove worked great first season. 2nd season the secondary combustion didn't seem quite up to par; less heat output from the heat-radiating fins in back. This season, even less, although the stove still seems to heat the room OK but most of the heat comes from the sides and top, not the back.
Another quirk I notice is that the andirons keep loosening up, to the point that they just barely hold the wood away from the glass, unless I periodically tighten the bolts that hold them in place, something I have performed often enough now, that I find it easy to do even when the stove is hot, just before a reload. The only thing I can think of that causes the bolts to back out is the heat/cooling cycle of the steel bolts and iron casting.
Don
I was concerned about creosote build-up because my AB doesn't seem to be working up to par, but the total soot/creosote accumulation doesn't seem much different from previous burning seasons. Next step is to check the CP and shoe brick to see if any of the secondary air passages are stopped up.
My question: has anyone else had difficulty removing the shoe brick? Last year the guy from the store, who installed the stove two years earlier, came to check and clean it. He couldn't get the shoe brick to budge after removing all the other bricks surrounding it, so I don't think he was able to clean it properly. I plan to do my own cleaning from now on, because I suspect he doesn't know the stove very well; he had to borrow my owner's manual to figure out how to re-assemble the bricks, and I didn't like way he was poking inside the CP with the vacuum cleaner hose. The bottom of the shoe brick seems stuck tight to the cast-iron part that supports it. All the other bricks are slightly loose and can be budged, even with all the metal clips in place. I'm wondering if I have missed something in the procedure; I don't want to force anything too much since both the shoe brick and CP are expensive to replace.
The stove worked great first season. 2nd season the secondary combustion didn't seem quite up to par; less heat output from the heat-radiating fins in back. This season, even less, although the stove still seems to heat the room OK but most of the heat comes from the sides and top, not the back.
Another quirk I notice is that the andirons keep loosening up, to the point that they just barely hold the wood away from the glass, unless I periodically tighten the bolts that hold them in place, something I have performed often enough now, that I find it easy to do even when the stove is hot, just before a reload. The only thing I can think of that causes the bolts to back out is the heat/cooling cycle of the steel bolts and iron casting.
Don
Not sure why it is tight... mine has always been loose, just resting in place like the other bricks. It did break in half, and I put it back together with cement. As far as I can tell, the shoe seems mostly self-cleaning. I vacuum out the holes occasionally, which can be done with it in place... I have never seen any deposits underneath it, where the secondary air comes in. If there is a problem, it is more likely with the CP behind the shoe
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