Yes, your stove is over drafting... Blame the ...

[bholler]

There fewer than 2 stoves that can run as low as ours in kg/h and produce as low emissions. Can we work on your stove...perhaps swap out the cat? It should not stall in low burn rates. Is your stack 15' +.....let's not consume this thread, just give me a call. 509-522-2730.

I will do that. But give some basics here. I have 21' but it goes through the wall so it works out so the draft is within spec. .05 to .06. it was a bit low but I reworked the pipe and got it right.

I actually think the cat is currently on its last legs. This is the 3rd season and it doesn't get active as fast or stay active as long. But I could always stall it like that even when the cat was new. I will call you tomorrow

 

[ABMax24]

I know a certain stove manufacturer/nerd that designed a stove that had 3 tiered cats, multi O2 sensors, 3 different fan systems for air introduction etc. Emissions were nearly zero. One day an EPA random compliance audit took place at the factory. The guy shared the prototype with the inspector.

When asked. "what's keeping you from bring it to market?" my friend said 2 things. First the cost. It would retail at $20-$30k. Second, his research showed 97% or more wood burners preferred low tech for minimal technical issues. He is still a dear friend and has not shelved the project!! I've seen the stove...it has a future.

I think that would be interesting to see, in many ways I believe its only a matter of time before more manufacturers head to electronics to control the stove.

In many way I'd liken wood stove technology to a 2-stroke vs 4 stroke engine. A 2 stroke is simpler to build, cheaper, and has less moving parts. The problem comes in with tuning, tuning with port timing/sizing, changing tuned pipes and finnicky air fuel ratios make them dirtier and more temperamental. Where a 4 stroke has more moving parts and is costlier to build, but everything can be precisely controlled with hard parts such as cam profile, or in the electronic tuning.

Once electronically controlled stoves hit the market things like draft issues will be a thing of the past, as the computer will either automatically adopt to changes via sensor inputs, or these parameters could be programmed into the stove at the time of install.

 

[Highbeam]

I will do that. But give some basics here. I have 21' but it goes through the wall so it works out so the draft is within spec. .05 to .06. it was a bit low but I reworked the pipe and got it right.

I actually think the cat is currently on its last legs. This is the 3rd season and it doesn't get active as fast or stay active as long. But I could always stall it like that even when the cat was new. I will call you tomorrow

I thought all operators should find that low setting at which their cat would barely not stall. I know I can always stall my cat if I just swing the stat dial to full low.

 

[Crocks]

I think that would be interesting to see, in many ways I believe its only a matter of time before more manufacturers head to electronics to control the stove.

In many way I'd liken wood stove technology to a 2-stroke vs 4 stroke engine. A 2 stroke is simpler to build, cheaper, and has less moving parts. The problem comes in with tuning, tuning with port timing/sizing, changing tuned pipes and finnicky air fuel ratios make them dirtier and more temperamental. Where a 4 stroke has more moving parts and is costlier to build, but everything can be precisely controlled with hard parts such as cam profile, or in the electronic tuning.

Once electronically controlled stoves hit the market things like draft issues will be a thing of the past, as the computer will either automatically adopt to changes via sensor inputs, or these parameters could be programmed into the stove at the time of install.

I love two strokes. The smell, the sound, simplicity and so on.

Wood stoves on the other hand all I ask for is a long atleast 12 hour burn time, enough coals to toss full size splints / load ontop of and it light up, close down and repeat. Then comes all the variables to achieve such. Crazy wood stove world we live in

 

[bholler]

I thought all operators should find that low setting at which their cat would barely not stall. I know I can always stall my cat if I just swing the stat dial to full low.

That's what I thought

 

[bholler]

I think that would be interesting to see, in many ways I believe its only a matter of time before more manufacturers head to electronics to control the stove.

In many way I'd liken wood stove technology to a 2-stroke vs 4 stroke engine. A 2 stroke is simpler to build, cheaper, and has less moving parts. The problem comes in with tuning, tuning with port timing/sizing, changing tuned pipes and finnicky air fuel ratios make them dirtier and more temperamental. Where a 4 stroke has more moving parts and is costlier to build, but everything can be precisely controlled with hard parts such as cam profile, or in the electronic tuning.

Once electronically controlled stoves hit the market things like draft issues will be a thing of the past, as the computer will either automatically adopt to changes via sensor inputs, or these parameters could be programmed into the stove at the time of install.

Unless they are lazy and say screw efficiency I will just slap a barometric damper in the pipe. Lol

 

[BKVP]

I think that would be interesting to see, in many ways I believe its only a matter of time before more manufacturers head to electronics to control the stove.

In many way I'd liken wood stove technology to a 2-stroke vs 4 stroke engine. A 2 stroke is simpler to build, cheaper, and has less moving parts. The problem comes in with tuning, tuning with port timing/sizing, changing tuned pipes and finnicky air fuel ratios make them dirtier and more temperamental. Where a 4 stroke has more moving parts and is costlier to build, but everything can be precisely controlled with hard parts such as cam profile, or in the electronic tuning.

Once electronically controlled stoves hit the market things like draft issues will be a thing of the past, as the computer will either automatically adopt to changes via sensor inputs, or these parameters could be programmed into the stove at the time of install.

Well other research is focusing on the chimney system being smarter. Imagine a smart cap that would control the amount of draft, after all fuel and draft are outside the control of stove designers. It would still increase cost of installation, but if you had an older stove, would a smart cap for say $1500 be a good option versus $10,000 or more for a stove? We'll see.....

 

[kennyp2339]

Well other research is focusing on the chimney system being smarter. Imagine a smart cap that would control the amount of draft, after all fuel and draft are outside the control of stove designers. It would still increase cost of installation, but if you had an older stove, would a smart cap for say $1500 be a good option versus $10,000 or more for a stove? We'll see.....

That is something I would be very interested in, I have so much variables in my chimney draft, the one size fits all approach does not fit my needs. I literally go from a .06 to a .18 just from a change in wind direction, the higher draft just happens to come from my winter prevailing winds, so it is manageable, but its annoying to at the same time.
Now with new designs, how much can a homeowner do to service or fix a problem that may occur? I know in the farming community there is a big push with right to work on equipment (the big green machines installed software locks on electronic hardware forcing expensive service calls for simple fixes) Just food for thought while the industry is in the planning stages of new tech.

 

[moresnow]

That is something I would be very interested in, I have so much variables in my chimney draft, the one size fits all approach does not fit my needs. I literally go from a .06 to a .18 just from a change in wind direction, the higher draft just happens to come from my winter prevailing winds, so it is manageable, but its annoying to at the same time.
Now with new designs, how much can a homeowner do to service or fix a problem that may occur? I know in the farming community there is a big push with right to work on equipment (the big green machines installed software locks on electronic hardware forcing expensive service calls for simple fixes) Just food for thought while the industry is in the planning stages of new tech.

Old big green machines are brining huge bucks at auction right now because of this very reason. Stupid expensive service calls for what is quite simply... Goofed up eeeeelectronic gadgets/gizmo's that are causing crazy down time in a mother nature limited time frame. Noooo good.

 

[SpaceBus]

This is mostly a problem faced by smaller farmers who are buying the big green computer controlled tractors second hand. The original owners get all the dealer support. I could see the same thing happening to the second or third owner of a computer controlled stoves. Especially with the way folks change out their home every five years.

 

[moresnow]

This is mostly a problem faced by smaller farmers who are buying the big green computer controlled tractors second hand. The original owners get all the dealer support. I could see the same thing happening to the second or third owner of a computer controlled stoves. Especially with the way folks change out their home every five years.

Um. No. The original owner's are just as unhappy (if not more so) with down time as the smaller farmer's. Now back to the topic

 

[MTASH]

The point I was trying to make is not all buyers of wood stoves read the manuals and of those that do most discard the technical suggestions.

Sit at my desk for a day and you'll see it!

To be fair though, do you think the dealers should attempt to better inform buyers? I am a technical person, engineer by profession, and knew I had a sub-optimal chimney based on the recommendations in the Ashford install manual. It was a 9'-4" 6x10 clay flue, "But it always worked fine with my Schrader". The new EPA stoves were a different animal to me, and I was looking for dealer's advice, thinking they'd have real world experience and could help explain. I talked to two different dealers (ironically located in the two towns you mentioned in a previous post!), and this is what happened:

1) Dealer #1 was reluctant to sell me a BK at all. They simply don't work well at my elevation (5400'). No discussion about how I could modify/improve my chimney, and I left there feeling like they really just wanted to push another brand.

2) Dealer #2 was more than willing to sell me the stove, and didn't attempt at all to steer me to another brand, but again no discussion about install until I prompted them. After learning about my chimney, he suggested I go ahead and do the install, but did say that I might need to install a liner if it doesn't work out.

I chose Option 2. I ran the stove on the existing chimney for the last half of the season, and it worked reasonably well, but certainly not optimal. At that point I'd spent quite a lot of time on this forum and knew I needed a insulated liner (for more than one reason) and to add height. So I ended up installing a liner prior to the next season. I still only have 12', but it is correctly sized and insulated which made a huge difference. Although knowing what I know now, I don't recommend anyone run an Ashford on less than 15'.

I realize this thread started out as an overdraft discussion, but the point is that I don't think your average buyer is going to digest all the information in the manual, and certainly doesn't spend time on forums like this other than to research reviews on stove brands (as I did). It would be helpful to have dealers that take the extra step to review the install rather than simply sell a stove (or not, as in my example).

 

[BKVP]

To be fair though, do you think the dealers should attempt to better inform buyers?

YES!! Some dealers are superb, others not so much.

I am a technical person, engineer by profession, and knew I had a sub-optimal chimney based on the recommendations in the Ashford install manual. It was a 9'-4" 6x10 clay flue, "But it always worked fine with my Schrader". The new EPA stoves were a different animal to me, and I was looking for dealer's advice, thinking they'd have real world experience and could help explain. I talked to two different dealers (ironically located in the two towns you mentioned in a previous post!), and this is what happened:

1) Dealer #1 was reluctant to sell me a BK at all. They simply don't work well at my elevation (5400'). No discussion about how I could modify/improve my chimney, and I left there feeling like they really just wanted to push another brand.

Good thing there are forums like this one where you can come for assistance ! We try very hard to educate and train dealers but the turnover in staff in dealerships is too frequent for the continuity that is needed.

2) Dealer #2 was more than willing to sell me the stove, and didn't attempt at all to steer me to another brand, but again no discussion about install until I prompted them. After learning about my chimney, he suggested I go ahead and do the install, but did say that I might need to install a liner if it doesn't work out.

We admonish all dealers to inform prospective owners to use insulated liners in masonry chimney systems. You know I have seen some really outstanding folks in this business. They qualify the homeowner first for intended use & expectations; second experience in wood heating; third intended install specifications; fourth discussion on fuel and lastly price. They have great closure rates in selling because they are informed and share their knowledge and experience with their customers.

I chose Option 2. I ran the stove on the existing chimney for the last half of the season, and it worked reasonably well, but certainly not optimal. At that point I'd spent quite a lot of time on this forum and knew I needed a insulated liner (for more than one reason) and to add height. So I ended up installing a liner prior to the next season. I still only have 12', but it is correctly sized and insulated which made a huge difference. Although knowing what I know now, I don't recommend anyone run an Ashford on less than 15'.

I realize this thread started out as an overdraft discussion, but the point is that I don't think your average buyer is going to digest all the information in the manual, and certainly doesn't spend time on forums like this other than to research reviews on stove brands (as I did). It would be helpful to have dealers that take the extra step to review the install rather than simply sell a stove (or not, as in my example).

 

[ABMax24]

Well other research is focusing on the chimney system being smarter. Imagine a smart cap that would control the amount of draft, after all fuel and draft are outside the control of stove designers. It would still increase cost of installation, but if you had an older stove, would a smart cap for say $1500
be a good option versus $10,000 or more for a stove. We'll see.....

The way I see it a couple temp probes, a small microprocessor, and an actuator is all that's needed at the current time to control a stove and pass emissions. It shouldn't be a costly endeavor.

It could even be a manual stove with a built in automated flue damper to control draft. A very simple pressure sensor, basic microcontroller, damper and actuator would be all that's needed, and would solve 95% of high-draft related issues. It could even have a temp sensor built in to prevent an operator induced overfire.

 

[ABMax24]

I love two strokes. The smell, the sound, simplicity and so on.

Wood stoves on the other hand all I ask for is a long atleast 12 hour burn time, enough coals to toss full size splints / load ontop of and it light up, close down and repeat. Then comes all the variables to achieve such. Crazy wood stove world we live in

So do I, I love the fact that I can make 220+hp from my turbocharged 800cc snowmobile engine at 9lbs boost. But do I want that maintenance and temperamental nature in my daily driver, no.

I think most people feel the same about wood stoves, if I had one that required lighting and walking away, then reload again in 12 or 24 hrs and walk away again with the stove controlling output would be awesome. The closest stove to this on the market now seems to be the BK stoves, which is why I believe they've developed a cult-like following.

 

[sadpanda]

A 4" pipe on a 6" stove will not have enough volume on startup and will smoke back into the house. Draft measurement is only one part of the equation. You also have to have the correct volume.

I did not think sweeps/installers did calculations? You keep saying calculations are useless because there are too many variables to consider yet you site equations. The Slkirk Chimney and Venting Sizing handbook is full of calculations and tables... Nobody uses them?

Why should key dampers be avoided??? If you are using it to bring draft into spec you would not have smoke spillage at all when you open the door.

Also the "magic EPA honeycomb thing" only works.
1 if there is one which many stoves don't have one.
2 if there is enough temp to keep that cat active.

Re: seasoned wood/magic combustor I was purposefully being obtuse... The default answer for creosote formation is always 'do not burn green wood'

How do you know a pipe smaller than 6in can not support stove startup? Given the weight given to real world experience over science, have you ever done a 5" install? Did it also include a key damper?

I'm not saying key dampers should be avoided. I'm saying they are:

• subject to user error
• not effective in controlling variable draft situations
• apparently can only solve slight overdraft situations
• compared to properly sizing the flue system from the onset, seems like a band-aid

Are you are saying a key damper is a set it and forget it device in your installations? Even fully closed, my key damper does not bring me in spec. That said, if I do not open it prior to door opening, I get smoke spillage. ¯\_(ツ)_/¯

Ok you can run what ever numbers you want but the fact is that it is not allowed because doing so has caused to many house fires and they determined it was unsafe.

Again your numbers don't take into account the thousands of variables that go into this. And actual real world experience tells us elevating the air intake carries to much risk.

My numbers are admittedly crude... I keep asking for smarter people than me to jump in and enhance them but the most logical player (@BKVP) seems content sitting back. Your solution is to not use math at all and simply intuit everything from your years of experience?

I found this excel sheet which addresses at least some of those thousands of missing variables...

So only things that cause instant death every time should be against code? What about possible death say 50% of the time? 10%? 5%? 1%?

I know as a professional if one of my installs cause a death I couldn't live with myself. Even without death the loss of a house is not something I am willing to risk for my customers.

Honestly this is exactly what I'm driving at and why this is so damn frustrating. MFG's have put all of the risk and liability squarely on your (installers/sweeps) shoulders... Anything YOU do to try and make the installation safe and functional is ILLEGAL! How does anyone square this? I'm looking at NFI, WETT, CSIA, National Sweep Guild etc. Hell, even the EPA. Aside from making money, why force certification under conditions that do not exist in the real world?

Are you comfortable with this liability? Is your local guild/CSIA/liability insurer/local fire marshal/local building inspector/federal judge? Why hasn't this alphabet soup of specials banded together and put this back on the powers that be (aka MFGs)?

So to summarize the current dialog:

<owner>: I have too much draft
<mfg>: follow the guidelines NOT in the manual. call a sweep. if you overfire the stove, the stove will break and you will die.
<sweep>: here is a key damper. Its illegal for you to use but its $8 and easy to install. Here is your invoice.
<owner>: But I still have too much draft
<mfg>: yep. Our engineers knew that would happen, we could help buuuuh we can't 'cause EPAss-ho... call your sweep.
<sweep>: you need more key damper
<owner>: But I have an insert and there isnt' any room for another key damper. What about a barome...
<sweep>: CREOSOTE
<owner>: but what if the pipe was sma...
<sweep>: Yer dumb. Here is your invoice. see you next year.

 

[MTASH]

To be fair though, do you think the dealers should attempt to better inform buyers?

YES!! Some dealers are superb, others not so much.

I am a technical person, engineer by profession, and knew I had a sub-optimal chimney based on the recommendations in the Ashford install manual. It was a 9'-4" 6x10 clay flue, "But it always worked fine with my Schrader". The new EPA stoves were a different animal to me, and I was looking for dealer's advice, thinking they'd have real world experience and could help explain. I talked to two different dealers (ironically located in the two towns you mentioned in a previous post!), and this is what happened:

1) Dealer #1 was reluctant to sell me a BK at all. They simply don't work well at my elevation (5400'). No discussion about how I could modify/improve my chimney, and I left there feeling like they really just wanted to push another brand.

Good thing there are forums like this one where you can come for assistance ! We try very hard to educate and train dealers but the turnover in staff in dealerships is too frequent for the continuity that is needed.

2) Dealer #2 was more than willing to sell me the stove, and didn't attempt at all to steer me to another brand, but again no discussion about install until I prompted them. After learning about my chimney, he suggested I go ahead and do the install, but did say that I might need to install a liner if it doesn't work out.

We admonish all dealers to inform prospective owners to use insulated liners in masonry chimney systems. You know I have seen some really outstanding folks in this business. They qualify the homeowner first for intended use & expectations; second experience in wood heating; third intended install specifications; fourth discussion on fuel and lastly price. They have great closure rates in selling because they are informed and share their knowledge and experience with their customers.

Yeah, I agree that staff turnover and inexperience is probably a big issue that's not easily controlled. And I certainly don't want to throw dealers under the bus, as it's possible or even likely those individuals I spoke with may not work there anymore, but it was a bit disappointing nevertheless. Fortunately I was prepared, but Joe Schmow who doesn't know the right questions to ask may be in for a big surprise when they contact an installer after already dropping $$$ on a new stove. (apologies in advance to anyone actually named Joe Schmow).

 

[sadpanda]

The way I see it a couple temp probes, a small microprocessor, and an actuator is all that's needed at the current time to control a stove and pass emissions. It shouldn't be a costly endeavor.

It could even be a manual stove with a built in automated flue damper to control draft. A very simple pressure sensor, basic microcontroller, damper and actuator would be all that's needed, and would solve 95% of high-draft related issues. It could even have a temp sensor built in to prevent an operator induced overfire.

Kutzner & Weber is a German company that has a 100% automated control system that can be retrofitted to any stove. It uses temp probes, a draft inducer (if needed) a motorized intake damper and a motorized barometric damper. Can include additional fun things like integration with central HVAC, kitchen vent hood lockout (to prevent depressurization), a smoke ionizer, app control etc. Its expensive. I wanted to buy one on our last Euro trip but between trying to get it back in checked bags and wife approval, it was nixed.

So the Germans have decided barometric dampers are safe to use on wood burners... Math must work differently over there.

 

[sadpanda]

Yeah, I agree that staff turnover and inexperience is probably a big issue that's not easily controlled. And I certainly don't want to throw dealers under the bus, as it's possible or even likely those individuals I spoke with may not work there anymore, but it was a bit disappointing nevertheless. Fortunately I was prepared, but Joe Schmow who doesn't know the right questions to ask may be in for a big surprise when they contact an installer after already dropping $$$ on a new stove. (apologies in advance to anyone actually named Joe Schmow).

I too had a bad experience with my local dealer/sweep and ended up DIY... Hence this conversation.

I think the biggest issue is like all trades, the certification really doesn't mean anything... Certification does not guarantee quality of work, it only proves that one person at the company managed to pass a test.

 

[sadpanda]

The way I see it a couple temp probes, a small microprocessor, and an actuator is all that's needed at the current time to control a stove and pass emissions. It shouldn't be a costly endeavor.

It could even be a manual stove with a built in automated flue damper to control draft. A very simple pressure sensor, basic microcontroller, damper and actuator would be all that's needed, and would solve 95% of high-draft related issues. It could even have a temp sensor built in to prevent an operator induced overfire.

Yep... if I dont go the KW route here is my someday diy list:
Raspberry Pi, pressure sensor, my existing thermocouples, GM stepper motor controlled throttle body for intake, WBO2 sensor, motorized exhaust damper etc

 

[SpaceBus]

The way I see it a couple temp probes, a small microprocessor, and an actuator is all that's needed at the current time to control a stove and pass emissions. It shouldn't be a costly endeavor.

It could even be a manual stove with a built in automated flue damper to control draft. A very simple pressure sensor, basic microcontroller, damper and actuator would be all that's needed, and would solve 95% of high-draft related issues. It could even have a temp sensor built in to prevent an operator induced overfire.

Maybe that's cheap on the DIY end, but the R&D required to make it work for thousands of customers is a bit different. I think that's why the $10,000 figure was used.

 

[BKVP]

Maybe that's cheap on the DIY end, but the R&D required to make it work for thousands of customers is a bit different. I think that's why the $10,000 figure was used.

And the tech support for the next 20+ years! 20 years ago we discussed making another type of solid fuel stoves. So I called all my contemporaries in that same product sector and sought their opinions on a number of topics. Unilaterally I was told "You better build into the budget a tech team for the next 20 years". Maybe they all told me that to scare us from entering the market...maybe not.

 

[ABMax24]

Maybe that's cheap on the DIY end, but the R&D required to make it work for thousands of customers is a bit different. I think that's why the $10,000 figure was used.

Sure depending on the company, those used to building traditional stoves will find it a difficult and costly endeavor, those with computer/engine controls experience not so much, the components are cheap, the implementation is too for the right builder.

I think in many ways though the moral of this thread is that R&D isn't always done, the stove is built to pass the EPA test and UL certification and kicked out the door. It is far easier to build a stove that always runs a constant draft due to an automated draft control or automated inlet control than to build a standard stove that uses hard parts to attempt to compensate for varying draft conditions. Hence my 2/4 stroke comparison. I have no doubt an electronic stove would cost more, but I see 25% more being the limit, not 200-300%.

 

[john26]

Yep... if I dont go the KW route here is my someday diy list:
Raspberry Pi, pressure sensor, my existing thermocouples, GM stepper motor controlled throttle body for intake, WBO2 sensor, motorized exhaust damper et

Raspberry Pi may not be the best thing to use it will an analog to digital converter to make the thermocouples read it will also need an analog output preferably 4-20 ma or 0-20 ma signal. A Velcio.net Ace or branch might be a better solution having some analog I/O's and expansion ports can be added. Allen Bradley with RS logix would be great but costly especially for the software.

 

[begreen]

The way I see it a couple temp probes, a small microprocessor, and an actuator is all that's needed at the current time to control a stove and pass emissions. It shouldn't be a costly endeavor.

It could even be a manual stove with a built in automated flue damper to control draft. A very simple pressure sensor, basic microcontroller, damper and actuator would be all that's needed, and would solve 95% of high-draft related issues. It could even have a temp sensor built in to prevent an operator induced overfire.

Someone did that with a PE stove on this site several years ago. I've been meaning to chase that thread down to see if he is still around.