could this be the problem

[TruePatriot]

BeGreen,

Thank you for the link to the "Frank Ivy Classic." But (and no regrets here re: the link) I have now come to the conclusion that I am more thoroughly confused about EBT than I would have thought possible. I read all four pages of the thread, and it's no wonder I'm confused. The woman I spoke with at PE seemed very sure of herself when she asserted that "...the EBT controls only the SECONDARY air intake," despite the fact that she didn't know how big a round the stove would accept--again, she did admit she was guessing on the door-opening height.

However, after reading the following, from the thread you linked, I don't feel so bad about being confused by this woman:

by Frank Ivy:
“If Tom says he got the right poop from the right person (finally) at P.E., then what makes you think he’s wrong?”
I spoke with several folks at PE - no two agreed on EBT. I’ll check on the Ken guy.

by Thechimneysweep:
I published the description of the EBT mechanism shown above after speaking at length with a tech support person who either didn’t understand it herself, or didn’t describe it correctly, or was simply unable to formulate a clear enough description to penetrate the high density matter at this end. The EBT mechanism opens and closes an intake hole separate from the draft control.

I found this (from the "Frank Ivy Classic" thread you linked to, above) interesting, however, as it supports what this woman told me, about the EBT metering secondary air only:

Thechimneysweep (hereinafter "The Sweep"):
Craig, all the old thermostatically controlled woodstoves I can remember used the bimetallic coil to open and close the primary air supply. From my sweeping days, I can tell you these tended to form a LOT of creosote, as they would smolder the fire in pulses throughout the duration of the burn. The beauty (and maybe the patentability) of the EBT technology is that it controls a secondary air intake, not the primary air control. It actually prevents the smokey, smoldering fire that so many of the old thermostat stoves created.

I added the bold in all cases, above. I do not have a dog in this hunt at present, as I have much work to do to install my new Englander 30-NC (beginning with driving upstate to go pick it up--lol Good thing I needed to burn the 3 hours of gas to visit the property anyway). However, if PE's EBT really is doing all of the wonderful things that The Sweep says it is (opening the secondary intake during both low temp and high temp. scenarios, all with only one bimetallic spring, depending upon what is needed to maximize burn times) then it really does sound like worthwhile technology.

I didn't take the time to try to fully understand everything The Sweep was saying, about how the EBT can both open the air intake (whichever one[s?] it's actually controlling) during high temps and close it during other occurrences of high temps., depending upon which of four stages of fire the burn is at. But I think that could be possible, even while using only one bimetallic element, IF that angled-plate draft-valve-thingy in The Sweep's drawing works similar to the principle of an "overcenter" mechanism. IOW, if it lifts the "A-side" of a two-flapped "butterfly" air intake valve, initially, for low temps, but then, due to continued expansion of the bimetallic element, sensing EVEN HIGHER TEMPS., it then continues to rotate the angled air intake "butterfly," until (what I'll call ) the "B-side" of the butterfly valve then shuts the same hole that the A-side initially opened, well, then, I could see that.

I can't actually see that that's what's happening in The Sweep's diagram, but his diagram did allow me to envision what I described, above.

This would also reconcile "ermite's" observation of the air intake being opened by the EBT as the bimetallic element initially sensed higher temps with Thechimneysweep's contention that high temperatures could also cause the same air intake to close, again, all being driven by only one bimetallic element.

I'm just saying that the "overcenter" scenario I described, above (the "A-side/B-side" of an intake butterfly-valve) could explain what The Sweep is alleging, i.e., that a single spring could both open and close a draft intake, even while temps are simply rising, rather than rising temps. causing the air intake to close, and low temps causeing it to open, which is what one would logically assume, as the simplest scenario.

And of course, that sheds zero light on which of the two forms of intake air are being metered by the system, i.e., the primary or the secondary.

Does anyone else see what I'm saying? I only ask as a way to check whether I accurately understand what Thechimneysweep was saying in the thread BeGreen linked, above. I am certainly not trying to jump in the middle of this PE thing.

I also still want to know if I was misinformed by PE, and that in fact, as Gunner, Jimbob and others have said, the EBT really does meter primary air in addition to (or instead of?) secondary air, as the PE factory rep. told me.

Having never even seen a PE in person, I feel I'm out of my league here, and I'm definitely out of time, as I'm packing to go get my new stove, but thank you, Mark, for that link. It truly is fascinating, and it seems to me that the plot is only thickening, re: EBT. (As Craig noted, it's an amazing number of posts for a seemingly-simple technology.) I will be most interested in future developments. If I don't respond for a couple of weeks, it's because I'll have very ltd. web access, not because I'm at a loss for words, as some here have been quick to point out, in prior sorties--lol).

Thanks again,

Peter

 

[swestall]

I do the same thing as Gunner said on P1; I did that yesterday and heated the house all day (27 outside) with just a small bit of junk wood and the coals....

 

[begreen]

Confused? I can't understand why ;-).

Here's what Tom has posted on his site:
"The EBT technology was designed to maximize burn times for each load of fuel by delivering a burst of combustion air to the main and secondary fires when needed, even when the draft control is turned down far enough to create the longest possible burn.

Basically, the EBT device is a pivot plate which is mounted over a hole in the stove's air intake plenum so that it covers and uncovers the hole when it pivots. A bimetallic coil is attached to an actuator arm that pivots the plate so that when the firebox begins to cool below a certain point, the coil contracts, and the entire assembly hinges open to uncover the intake hole and provide extra air to the fire. As the burn rate increases from the inflow of oxygen, the firebox heats back up and the coil expands, lowering the base plate back down to seal the hole in the air intake plenum, without changing the original slide draft setting."

 

[Gunner]

Since spike's film loop is not working I will post some pics when I get home tomorrow.

I could be wrong but I don't see how the secondary could be metered by the EBT.

The secondary air supply runs down from the baffle along the back of the firebox like most steel non cats, it ends just below the firebox floor and can be seen when you remove the ash pan. It is nowhere near the EBT. It is open all the time and is a straight shot up and into the baffle. I know this because I have experimented with plugging it, which will stop ALL air to the baffle...good to know in an emergency.

The EBT is a sealed unit at the front right on the bottom of the stove next to the primary air inlet.

 

[begreen]

Interesting info Gunner. Let me be sure I understand this correctly. Are you saying that if the stove is connected to an OAK, it is still drawing secondary air from the interior of the house?

 

[Gunner]

An oak would connect to the housing under the stove, which in the case of my legged model holds the ash pan. Both primary and secondary air are drawn from this space. There is a 3"? knockout in the housing to connect the OAK to.

 

[thechimneysweep]

The lengthy discussion with Frank Ivy and others referenced above details my learning curve with PE's EBT technology. Part of the problem was (and still is) PE's reluctance to go into great detail about their patented device, part of the problem was PE's tech support personnel, who couldn't seem to agree about how it works, and part of the problem was my own inability to understand and then describe the function of the device.

That thread eventually resulted in the EBT page on our website at (broken link removed to http://www.chimneysweeponline.com/hoebt.htm)

As evidence that I finally got it right, PE tells me that they now direct inquiries about the EBT technology to that page.

To answer some specific questions above, the SECONDARY air supply tube in the Summit / Alderlea T6 is always open to a free supply of air, the inflow dictated by chimney updraft.

The intake that supplies air to the PRIMARY fire opens to an airbox similar to the sketch on our website: all air to the primary fire must pass through that airbox, and is controlled by a slide draft control.

So, you open the primary draft control, the air enters the airbox, and then flows into the firebox to supply air to the PRIMARY fire.

The EBT technology opens and closes a second hole into the same airbox, to supply more air to the primary fire as needed when you have the draft control turned down for the long burn.

This infusion of EBT air perks up the primary fire,

which increases internal firebox temperature,

which increases exhaust temperature,

which increases chimney updraft,

which draws a proportionately greater supply of air through the secondary air supply tube, which, again, is always open to a free supply of air.

So, when the EBT actuates, it supplies combustion air to the primary fire, which indirectly increases the combustion air supply to the secondary fire.

 

[Gunner]

So tom you need to fix that on your site

“The EBT technology was designed to maximize burn times for each load of fuel by delivering a burst of combustion air to the main and secondary fires when needed, even when the draft control is turned down far enough to create the longest possible burn.

Basically, the EBT device is a pivot plate which is mounted over a hole in the stove’s air intake plenum so that it covers and uncovers the hole when it pivots. A bimetallic coil is attached to an actuator arm that pivots the plate so that when the firebox begins to cool below a certain point, the coil contracts, and the entire assembly hinges open to uncover the intake hole and provide extra air to the fire. As the burn rate increases from the inflow of oxygen, the firebox heats back up and the coil expands, lowering the base plate back down to seal the hole in the air intake plenum, without changing the original slide draft setting.”

It's hard to convice people it aint so when they come armed with info from your site, quoting it like scripture. :lol:

 

[Andre B.]

The way I see it the EBT is controlling the primary air just like a person would be.

At startup there must be some override to get some primary air into the stove to get it going.

As the stove heats up the EBT starts to open up it's primary air, (this is an example of a positive feedback servo loop, these are unstable).

As the stove gets hotter the secondary burn starts to come into play and about this time the EBT goes over center, and the override needs to be closed. When that (the going over center) happens the EBT system is operating as a negative feedback servo system, higher temps in the stove close down the primary air.

Then as the wood burns down and the stove cannot maintain the high temps and secondary burn the EBT goes back over center (back to the positive feedback) so the primary air supply is cutoff more as temps drop. This is just what you want to keep a bed of hot coals.

 

[begreen]

Thanks for chiming in Tom. Gunner is correct, the bolded statement is the source of (at least my) confusion. Not scripture, but I want to know. I have a friend looking at buying this stove this week and I'd like to be accurate in describing how it works. I can't wait to actually get under this stove and see how it is put together for myself.

 

[thechimneysweep]

Hey Gunner,

The text you quote from our EBT page is accurate, and is the best way I could figure out how to say it, without the lengthy explanation in my post above. Most of the comments we get from visitors to that page ask for a shorter, simpler explanation, so I have tried to trim the verbiage where possible.

The EBT does introduce a burst of air to both the primary and secondary fires, directly to the primary fire, then indirectly to the secondary fire through the resulting increase in chimney draft.

Here's the simplest cause and effect statement I can come up with: EBT opens, both fires get more air.

 

[begreen]

The EBT does introduce a burst of air to both the primary and secondary fires, directly to the primary fire, then indirectly to the secondary fire through the resulting increase in chimney draft.

I like this statement. It's unambiguous and not too technical.

 

[thechimneysweep]

Ok. Here's how it now reads:

The EBT technology was designed to maximize burn times for each load of fuel by delivering a burst of combustion air to the primary fire (and indirectly to the secondary fire through the resulting increase in chimney updraft) when needed, even when the draft control is turned down far enough to create the longest possible burn.

What do you think?

 

[iceman]

I had Icemans coal problems last year. This year I rarely have that problem. At 27' of chimney, draft is not an issue, maybe too much draft, but certainly not enough.
This year, I can count on one hand the amount of times I had serious coal depth that hindered me. Ice, I still say slap a 4' pc of galvanized on the top, screw 2', go for 4'. See if that improves draft. As far as the coals, I think you will find that this time next year after learning more about your stove & the wood you burn, you will have less coals. I fill it to the gills, get it blazing, cut back around 500 or so, cruises to 750 and in the morn I got just the right amount for a reload. If I have a bit many coals, I open the air up all the way and in an hour Its feeding time. Not knocking you, but I think maybe not all, but some of this is part of your learning curve.

i will definitely agree that it does have something do with me.. but thats why i am here to find out whta i am doing wrong... i am trying everything (except that 4 ft section but that is next) to see if its really me or more so just how the stove is gonna go
there is someone else here with a 22 ft run i believe and the same problem/ issue
there is also another that like the idea of a deep coal bed .. i do believe i will be able to tweek it but this is something i think i have to learn how to mange as even you have said there are times when you have this problem you just let it run for an hr.... and there is no way i am going up to 27' lol
but with this whole EBT system it seems like it just gives enough air so the fire won't go out instead of giving it enough to keep burning.... meaning in the beginning when the fire gets going you get lots of secondary but in the end when i have a huge bed of coals ebt should give me more air to burn them down .... i think i am asking for a cpu cintrolled woodstove...lol

 

[Gunner]

Ok. Here's how it now reads:

The EBT technology was designed to maximize burn times for each load of fuel by delivering a burst of combustion air to the primary fire (and indirectly to the secondary fire through the resulting increase in chimney updraft) when needed, even when the draft control is turned down far enough to create the longest possible burn.

What do you think?

Sounds good

 

[BrotherBart]

ice since a major marketing point is burn time, defined as until the last coal is out, it will be a cold day in hell before PE re-redesigns EBT to burn that last coal faster.

 

[begreen]

Ok. Here's how it now reads:

The EBT technology was designed to maximize burn times for each load of fuel by delivering a burst of combustion air to the primary fire (and indirectly to the secondary fire through the resulting increase in chimney updraft) when needed, even when the draft control is turned down far enough to create the longest possible burn.

What do you think?

I like it Tom, though I would break it into sentences to make it more readable. Maybe something like:

The EBT technology is designed to maximize burn times for each load of fuel. It does this by delivering a burst of combustion air to the primary fire when needed and indirectly to the secondary fire through the resulting increase in chimney updraft. This occurs even when the draft control is turned down far enough to create the longest possible burn.

 

[Gunner]

but with this whole EBT system it seems like it just gives enough air so the fire won’t go out instead of giving it enough to keep burning....

If you want the fire to have more air..open up your air control.

The EBT CANNOT reduce the air below YOUR primary air control setting...it can only ADD air, in the event your fire starts to smolder.

I get the feeling some people think the EBT is completely closing off the air once in the coaling stage. Not true, the EBT closes once the fire stops responding (fails to heat back up)and stops giving that extra shot of air. Your original air setting, which is seperate from the EBT, is the same and not restricted by the closing of the EBT.

 

[iceman]

ice since a major marketing point is burn time, defined as until the last coal is out, it will be a cold day in hell before PE re-redesigns EBT to burn that last coal faster.

ok okok ok not the last coal but having 4-6 inches of coals??? in big chunks maybe the ebt sensor or what ever it is should be in the back of the tove because that is where the coolest part is?? ( i don't even know where the ebt is now) but just a thought if it is happening to many of us with different applications it makes me wonder.... but then again as i said before if the coals count as burn time.. geez i am 12+ hrs easily just after 8 not enough heat

 

[thechimneysweep]

Thanks BeGreen, you're an editor at heart. I made the change, and eliminated the word "even", because if you're not operating the stove at the lowest draft control setting, the EBT probably isn't ever going to kick in anyway.

Gunner, as I've mentioned before, you've got the EBT concept down.

Andre, looks like you've got it too.

Finally, a synopsis of the postings on the original question: closing the draft control is a means to overcome the force of the chimney updraft to LIMIT the flow of air through the stove. So, if you suspect that insufficient chimney updraft is causing your excessive charcoal problem, don't contribute to the problem by choking down the air supply so much at the bottom end. At the charcoaling temperatures that exist in the firebox at the end of a long burn, the EBT is in park, and won't supply any extra air to the coals.

 

[iceman]

ok so giv e my sweety more air... but that means my ebt will never kick in???
darn ... i like telling people i have EBT and they don't..oh well .. i will give her more air .. i am going to put it directly under the L overnight

 

[Stevebass4]

As you already know you are on the low end of the required height. That being said I have 24' of chimney and also get huge amounts of coals in the morning during cold weather and hard burning... IMO it's a blessing not a curse. Sometimes after 3-4 back to back full loads it will take the better part of the day to burn them down. I rake everthing forward and put 1 large SOFTWOOD split E/W. Stovetop temp will rise to 6-700...I am able to produce the heat I need while burning the coals down, I repeat this 2 or 3 times to burn everthing down. Start burning softwood and you will solve your problem. Agree with what craig said leave the air open more during your overnight burn, it will peak out alittle higher but you will have less coals in the morning.

if you have 24 feet and the same thing going on then wow i give up i will have to get softwood ... but here in the northeast where?
over the summer i will start collecting pine ... tree guys around here all they sell is mixed hard... or oak!

bring your truck and a HUGE chain saw - you can have all the pine you want!!

figure the tree i took down has at least 5 cords

 

[Gunner]

Thanks for chiming in Tom. Gunner is correct, the bolded statement is the source of (at least my) confusion. Not scripture, but I want to know. I have a friend looking at buying this stove this week and I'd like to be accurate in describing how it works. I can't wait to actually get under this stove and see how it is put together for myself.

Begreen,
I know the air has been cleared but here is the pic anyways... on the left in the spring loaded ash hole trap door, back left the knockout, back middle the secondary air intake, and front right the EBT "box", with the primary air control lever in the middle at the front.

 

[Gunner]

Gunner could I ask a favor? Could you please put a thermo on the corner of the front of your free standing Summit and measure the temp difference between the stove top temp and that one. I know that there has always been a hundred to two hundred degree difference between them with every stove I have ever owned and I would really like to know just how hot these guys are really burning these Summit inserts.

Thanks in advance.

The thermos I have dont fit on the spot by the corner of the door. I'm going to the hardware store, if I find a decent one that'll fit I'm going to get it. Will be nice to see the temp from the sofa instead of getting up anyway.

 

[iceman]

Thanks for chiming in Tom. Gunner is correct, the bolded statement is the source of (at least my) confusion. Not scripture, but I want to know. I have a friend looking at buying this stove this week and I'd like to be accurate in describing how it works. I can't wait to actually get under this stove and see how it is put together for myself.

Begreen,
I know the air has been cleared but here is the pic anyways... on the left in the spring loaded ash hole trap door, back left the knockout, back middle the secondary air intake, and front right the EBT "box", with the primary air control lever in the middle at the front.

is that knockout something you had to do or did it come like that... i had a knock on the shell of the stove but didn't know about that one..