EPA stove overfire... Any changes to regulations? Flue liner size change?

[sadpanda]

For what i understand you have one now. why don't you try it and post the results? Or you dont want to do it just for the sake of not accept it? What, you dont want to feel you are wrong?

I am posting results.... Assuming no fluke issue with the stove it appears I'm strictly dealing with an overdraft issue as per manometer results. I installed a key damper last year as 'recommended' however I am having to essentially close it completely in order to control draft. I also feel like I had more creosote buildup at the cap but that could be any number of things. Either way I was looking from advice from installers/professionals/seasoned owners that have dealt with this before to see if sizing down the liner was a better option.

At $500-$1000+ I'm not going to just buy a liner for funsies. That's why I started asking if there was some sort of stack height/temperature differential/cfm type calculation. I found something on engineering toolbox but I'm not sure its sufficient.

Really I think I'm just going to stick with 6in liner and the damper. Seems to be the least 'unapproved' way to get the job done. I need to split/test a few pieces of wood but I think my stock is pretty well dried this year... If all is good there I'll see how creosote buildup goes this year and adjust more next year if need be.

 

[edyit]

here come the fanboys, i don't have a cat in this fight (bad pun i know) but i can tell you that anything that is automated with moving parts will fail eventually, sometimes things stop working or just don't work right to begin with, its a fact of life

 

[lsucet]

I am posting results.... Assuming no fluke issue with the stove it appears I'm strictly dealing with an overdraft issue as per manometer results. I installed a key damper last year as 'recommended' however I am having to essentially close it completely in order to control draft. I also feel like I had more creosote buildup at the cap but that could be any number of things. Either way I was looking from advice from installers/professionals/seasoned owners that have dealt with this before to see if sizing down the liner was a better option.

At $500-$1000+ I'm not going to just buy a liner for funsies. That's why I started asking if there was some sort of stack height/temperature differential/cfm type calculation. I found something on engineering toolbox but I'm not sure its sufficient.

Really I think I'm just going to stick with 6in liner and the damper. Seems to be the least 'unapproved' way to get the job done. I need to split/test a few pieces of wood but I think my stock is pretty well dried this year... If all is good there I'll see how creosote buildup goes this year and adjust more next year if need be.

I know things happens and it is ok. Many here will help you including me when my lack of knowledge. i run one on 19ft and the other on 24ft chimneys and including when i run it hard nothing is overfiring. i have flue probe too installed on both. I think that something else is going there. post pictures and all that like other requested and i am sure they will help you to narrow down the cause.

 

[bholler]

For what i understand you have one now. why don't you try it and post the results? Or you dont want to do it just for the sake of not accept it? What, you dont want to feel you are wrong?

Well we have had quite a few reports here of overfiring couple that with the multiple warnings on the stove and in the manuals about not overfireing and i come to the conclusion that it is possible.

And no i am certainly not going to try to overfire a stove that does not even belong to me in my house. It has absolutly nothing to do with me being right or wrong just common sense. Not to mention my chimney is only 18' certainly not excessive draft.

 

[black smoke signals]

I’m with the OP on this issue having the same stove and set up here (except damper)with no burn in my stove for me with excessive draft like he has posted. My question to OP in overtire what does the cat thermometer read? I have thought at times in case of an over fire to tape over the t-stat hole to help control excess draft but concerned about damage to the cat. To this day I don’t burn in high wind watch.

 

[bholler]

I am posting results.... Assuming no fluke issue with the stove it appears I'm strictly dealing with an overdraft issue as per manometer results. I installed a key damper last year as 'recommended' however I am having to essentially close it completely in order to control draft. I also feel like I had more creosote buildup at the cap but that could be any number of things. Either way I was looking from advice from installers/professionals/seasoned owners that have dealt with this before to see if sizing down the liner was a better option.

At $500-$1000+ I'm not going to just buy a liner for funsies. That's why I started asking if there was some sort of stack height/temperature differential/cfm type calculation. I found something on engineering toolbox but I'm not sure its sufficient.

Really I think I'm just going to stick with 6in liner and the damper. Seems to be the least 'unapproved' way to get the job done. I need to split/test a few pieces of wood but I think my stock is pretty well dried this year... If all is good there I'll see how creosote buildup goes this year and adjust more next year if need be.

Have you had a dealer or sweep out to diagnose the issues you are having? I really dontvse going down to 5.5 doing anything i would stick with 6" and try to figure out what is going on.

The readings you are getting for draft exceed what i measure on most 30'+ chimneys.

 

[bholler]

I’m with the OP on this issue having the same stove and set up here (except damper)with no burn in my stove for me with excessive draft like he has posted. My question to OP in overtire what does the cat thermometer read? I have thought at times in case of an over fire to tape over the t-stat hole to help control excess draft but concerned about damage to the cat. To this day I don’t burn in high wind watch.

So you have overfires on your blaze king as well?

 

[black smoke signals]

Yes I do but only high winds where I’m trying to control draft

 

[black smoke signals]

Not an expert here just using common sense with high wind can the bypass lift up promoting this problem

 

[jetsam]

Well we have had quite a few reports here of overfiring couple that with the multiple warnings on the stove and in the manuals about not overfireing and i come to the conclusion that it is possible.

And no i am certainly not going to try to overfire a stove that does not even belong to me in my house. It has absolutly nothing to do with me being right or wrong just common sense. Not to mention my chimney is only 18' certainly not excessive draft.

If you have normal draft, functional gaskets, and normal fuel (wood)- you can't overfire that stove. Turn it to high, leave it there for a week, it will be fine.

I wouldn't have believed it either before I tried it. Last year's "polar vortex" was my test.

 

[lsucet]

Not an expert here just using common sense with high wind can the bypass lift up promoting this problem

I dont know on the insert but on the freestanding the cam keeps the bypass down. anyway in case of bypass leak, the tstat still controlling the burn rate.

 

[BKVP]

The OP did contact me. There is some slight deflection in the top plate. There is also some deflection in the base as well. Nothing that would be alarming.

What I think he is asking....has anyone run their unit on a smaller diameter liner? And yes, currently his stack is not excessive, but may get extended as I recall.

We were unable to support or provide substantial testimony for such a reduction.

As to the observation that the manufacturers need to provide a way for the installers to adjust for draft and that EPA has nothing to do with that...That is NOT correct. EPA has everything to with the fact that stoves cannot be adjusted in the field. They must, under Federal law, be manufactured precisely as tested and then certified. If there was a way for consumers/installers to alter the burn rates, other than as tested, it would not be legal to be made and sold. You all have read here before my posts about adding dampers to vent systems.

EPA has in fact undertaken some discovery as to how many wood heaters are sold/installed or later had dampers installed. Their concern is that not EVERYONE has overdraft situations, but some users might install a damper to simply lower the burn rate to extend burn times and in doing so burn lower and slower. The possible lower and slower burn rate could result in higher emissions with some stoves.

Air leaks around door gasket, glass gasket, bypass gasket, leaving door ajar during firing etc. can all lead to problems with any stove. Not that the OP has done any of this, but as other have said, it may not just be draft. He has seemed to measure the draft and in his chimney, for some reason it is high.

That is why he is exploring the smaller diameter liner. Bholler, have you used 5.5" on 6" stoves with success? Does the unit spill during reloading in the event the diameter is reduced?

BKVP

 

[black smoke signals]

Does elevation play a role here I’m at 6200 ft? The OP have some valid concerns he’s very well educated with this insert hoping to here more on where temperatures were taken and wood percentage- if he is running a high wind cap like I had.

 

[black smoke signals]

The OP said he has to close the t-stat shut to control draft in high winds now can the stove over fire because of the 3/8 hole on the stat?

 

[maple1]

I am posting results.... Assuming no fluke issue with the stove it appears I'm strictly dealing with an overdraft issue as per manometer results. I installed a key damper last year as 'recommended' however I am having to essentially close it completely in order to control draft. I also feel like I had more creosote buildup at the cap but that could be any number of things. Either way I was looking from advice from installers/professionals/seasoned owners that have dealt with this before to see if sizing down the liner was a better option.

At $500-$1000+ I'm not going to just buy a liner for funsies. That's why I started asking if there was some sort of stack height/temperature differential/cfm type calculation. I found something on engineering toolbox but I'm not sure its sufficient.

Really I think I'm just going to stick with 6in liner and the damper. Seems to be the least 'unapproved' way to get the job done. I need to split/test a few pieces of wood but I think my stock is pretty well dried this year... If all is good there I'll see how creosote buildup goes this year and adjust more next year if need be.

Do you have a picture of your manometer setup?

 

[bholler]

The OP did contact me. There is some slight deflection in the top plate. There is also some deflection in the base as well. Nothing that would be alarming.

What I think he is asking....has anyone run their unit on a smaller diameter liner? And yes, currently his stack is not excessive, but may get extended as I recall.

We were unable to support or provide substantial testimony for such a reduction.

As to the observation that the manufacturers need to provide a way for the installers to adjust for draft and that EPA has nothing to do with that...That is NOT correct. EPA has everything to with the fact that stoves cannot be adjusted in the field. They must, under Federal law, be manufactured precisely as tested and then certified. If there was a way for consumers/installers to alter the burn rates, other than as tested, it would not be legal to be made and sold. You all have read here before my posts about adding dampers to vent systems.

EPA has in fact undertaken some discovery as to how many wood heaters are sold/installed or later had dampers installed. Their concern is that not EVERYONE has overdraft situations, but some users might install a damper to simply lower the burn rate to extend burn times and in doing so burn lower and slower. The possible lower and slower burn rate could result in higher emissions with some stoves.

Air leaks around door gasket, glass gasket, bypass gasket, leaving door ajar during firing etc. can all lead to problems with any stove. Not that the OP has done any of this, but as other have said, it may not just be draft. He has seemed to measure the draft and in his chimney, for some reason it is high.

That is why he is exploring the smaller diameter liner. Bholler, have you used 5.5" on 6" stoves with success? Does the unit spill during reloading in the event the diameter is reduced?

BKVP

I have used 5.5 a few times because of space limitations. But i will not do it on a chimney under 25'. Because of that i have never had an issue. Another point to add is going down to 5.5 wont change the pressure measured by a manometer. It will change how the stove runs because it changes the volume and velocity in the stack but the pressure will not noticably change.

I have a bit of a side question for you. Dont take this the wrong way i am just curious. How do you guys get away with making stoves that you can turn down far enough that the cat stalls under normal conditions. While noncats are not allowed to shut the air down that far. Or under test conditions are you able to turn the thermostat down the whole way?

 

[moresnow]

Interesting read. Hopefully something explains this? Action. Reaction.... Gotta be a answer here.

Incase I've missed it. Have you had another set of eyes (or 2) inspect the entire stove and setup (BK dealer/staff/pro sweep or installer perhaps?). Sometimes I've looked at a issue a 100 times and still missed the obvious Embarrassing!

Just a thought. Best of luck.

 

[BKVP]

I have used 5.5 a few times because of space limitations. But i will not do it on a chimney under 25'. Because of that i have never had an issue. Another point to add is going down to 5.5 wont change the pressure measured by a manometer. It will change how the stove runs because it changes the volume and velocity in the stack but the pressure will not noticably change.

I have a bit of a side question for you. Dont take this the wrong way i am just curious. How do you guys get away with making stoves that you can turn down far enough that the cat stalls under normal conditions. While noncats are not allowed to shut the air down that far. Or under test conditions are you able to turn the thermostat down the whole way?

Easy...All stoves can stall. There were actual demonstrations shown to air regulators at a manufacturers facility. So whether it is a cat stall or secondary combustion stall it happens. I don't take the question the wrong way. That's why the stoves we make have a minimum air setting (hole in the blade or hidden elsewhere). Now there are guys going to go look.

 

[moresnow]

Now there are guys going to go look

It was my foremost and immediate inclination

 

[BKVP]

Bholler,

You know the idea of having a variable adjustment for draft is a great idea. I'm wondering if you could not just have a device that could ONLY be calibrated to let's say 3 positions. (Not infinitely variable as EPA would not agree to that).

Of course a manufacturer would have to test to all 3 positions and the method would need to be revised as well. (read very costly here)

Gas units have either adjustable or variable restrictor plates to help with draft. Ummmmm, your thoughts through PM or here appreciated.

BKVP

 

[begreen]

That is why he is exploring the smaller diameter liner. Bholler, have you used 5.5" on 6" stoves with success? Does the unit spill during reloading in the event the diameter is reduced?

It's allowable on Regency inserts I think, but I would also be concerned with smoke spillage with the sloped front of the Princess. Before making a permanent change of the liner maybe try a 6x5" reducer and 5" cap at the top of the chimney as a test.

 

[sadpanda]

I’m with the OP on this issue having the same stove and set up here (except damper)with no burn in my stove for me with excessive draft like he has posted. My question to OP in overtire what does the cat thermometer read? I have thought at times in case of an over fire to tape over the t-stat hole to help control excess draft but concerned about damage to the cat. To this day I don’t burn in high wind watch.

During what I'm assuming was overfire my cat probe went off the end of the scale and kept right on trucking...

Tape over the T-stat hole will do nothing. Msg/call BKVP.

I'm no BK fan boy, I've already stated I have misgivings about about the magical t-stat HOWEVER, given the level of customer service I've received thus far I would buy a used car from BK or just about anything else they are willing to sell.

Really I think the thermostat is like a wood wagon wheel... What I REALLY want is to buy one of these systems but its over $1k USD plus sneaking it in my luggage to avoid VAT plus hoping there are english instructions: http://www.kutzner-weber.de/fileadmin/kw_images/k+w_pdf/K+W_Ofenregelung.pdf That or DIY with a Pi project, but I digress. Maybe I'll like it better once I get it working as intended.

I'm at 900ft above sea. I have a run of the mill stainless rain cap, no special wind velocity deal. I am in an open field rural type setting where wind is constant 5mph min and frequently gusts up to 40 during storms... I would say 10mph with gusts to 20 is pretty much usual.

My local BK rep/sweep kinda pulled one over on me so I've not been inclined to call them back out. I'm a DIY guy anyway.

After talking with Chris, I purchased a Dwyer 460. I tested draft while operating and got very high numbers. I returned the 460 because I was not getting consistent numbers when switching scales. BTW dont buy that turd... they don't publish accuracy specs on that unit for good reason.

I ended up with this meter instead: https://www.amazon.com/gp/product/B072F5WD2L/?tag=hearthamazon-20

I installed a compression fitting/brass line just below the key damper. Again I'm not convinced this thing is giving me laboratory results, especially considering its a digital meter and draft flutters/varies alot AND I'm not using a tube probe... However numbers are in line with what I was getting with the Dwyer. Thats why I coupled this little adventure with three temperature probes.



Back to the subject.
1) I know from automotive experience that I will have much more precise metering if I put a reducer in my key damper adapter and run a 4" damper. This might make happier as 'slamming it shut' then trying to find the just off seat sweet spot is a pita.

2) If and this is a big IF, IF flue gasses act like automotive exhaust gases, despite still having sufficient theoretical temperature at the top of the stack to avoid creosote, I am probably seeing increase buildup because the loss of gas velocity. Any steamy vapor is not being carried out of the stack fast enough to stay atomized and is collecting and finally cooling during burn down.

3) Dropping the insulation from the liner would probably help but I can't

SO... I mentioned Engineers toolbox:

https://www.engineeringtoolbox.com/chimney-sizing-d_175.html
flue temp 426 C
outside temp 4.44 C
height 20 ft
0.48" H2O

https://www.engineeringtoolbox.com/natural-draught-ventilation-d_122.html
4.44 - outside temperature (oC)
426 - inside temperature (oC)
6.096- height (m)
0.1524 - duct hydraulic diameter (m)
6.096 - duct length (m)

RESULTS
Outside density (kg/m3): 1.272
Inside density (kg/m3): 0.505
Natural draught pressure (Pa, N/m2) : 45.9 (0.184" H2O)
Duct Velocity (m/s) : 10.2
Air Flow (m3/s) : 0.19
Air Flow (m3/h) : 667
Air Flow (cfm) : 393

Thoughts?

 

[begreen]

You know the idea of having a variable adjustment for draft is a great idea. I'm wondering if you could not just have a device that could ONLY be calibrated to let's say 3 positions. (Not infinitely variable as EPA would not agree to that).

One of the designs at the Alliance for Green Heat 2018 Wood Stove Design Challenge has an option for this exact issue. The problem with the EPA tests is that they are with a fixed chimney height of 15'. That only covers the average single story home and not all the other normal variations from mobile homes, basement installs and 2 story with an attic.

 

[sadpanda]

It's allowable on Regency inserts I think, but I would also be concerned with smoke spillage with the sloped front of the Princess. Before making a permanent change of the liner maybe try a 6x5" reducer and 5" cap at the top of the chimney as a test.

kinda cant... well not easily. The chimney has already been raised by the mason so I have no liner. Well... I have it sitting out back waiting for the recycler but its several ft too short

Thats why I'm trying to suss this out with a little more math/finesse/experience because I have to buy a new one.

 

[sadpanda]

One of the designs at the Alliance for Green Heat 2018 Wood Stove Design Challenge has an option for this exact issue. The problem with the EPA tests is that they are with a fixed chimney height of 15'. That only covers the average single story home and not all the other normal variations from mobile homes, basement installs and 2 story with an attic.

Thats why I have a big tech boner for the fully automated control system I linked.... Ya its over over engineered in typical german fashion but it controls inlet air, fans, flue gas temp, flue barometic pressure, the works.