Secondary burn issues?

[jmb6420]

This pertains to a Lopi Endeavor 2020. When burning, the stove can be cruising along for 30-45 minutes with flue temps of around 600-650f. My normal cold start involves leaving it open until flue temps reach 600 then closing the damper and shutting primary air down to about 50%. I let the temps climb up to about 750f then start shutting it down bringing down the flue temps to 600-650f. After the fire settles in for awhile it seams like the secondaries switch on the afterburners and I can watch my flue temps climb all the way up to 850f with the primary air shut down completely.

I have approx. 21 feet with 2 45degree elbows. I emailed Travis Industries and was told that an inline damper is acceptable for this stove.
Would putting in an inline damper help with controlling the secondary burn or would that trap more of the heat in the stove and make the temps even higher? Am I over thinking this? Are these stoves supposed to burn that much hotter than their predecessors?


I emailed Travis Industries and am confused by the responses with Travis and hopefully someone here can elaborate.

Me:

I own a 2020 Endeavor. Sometimes after the secondaries take off it is uncontrollable. I’ll have air shot down all the way and watch my flue temps climb to 850f. Is it okay to install a key damper on this stove? I have duravent double wall pipe and would like to add the duravent adapter/damper. 6DVL-ADWD Travis Answer: Thank you for purchasing one of our units. Thank you for purchasing one of our products. Unfortunately to meet the current EPA requirement there has to be a specific amount of air to allow for a clean burn. There are several areas on the unit for the air supply that cannot be blocked or restricted. An inline damper would be fine. Me: Thank you for the response. Can you tell me what the recommended draft for this unit is? I can’t find it anywhere in the manual. Travis Answer: Not sure what you mean? Me: I figured the stove was designed and tested to work best at a specific draft measurement. Such as .3 in. H2O. Travis Answer: Draft is not part of the testing requirement so we don’t have any numbers. All of this from Travis Industries was from a guy with the following signature line: XXXX XXXXXX Customer Service/Technical Support Department NFI Certified Master Hearth Professional Travis Industries, Inc.

 

[Todd]

Have you tried turning your stove down sooner? I usually start shutting down when my flue temps hit 500 unless it’s a sluggish draft weather day then I may go up to 600. I go in 3 stages, wide open til I hit 500, medium, then low or final desired setting. Every time I adjust the air down I wait til the stove flue temps recover up to 500.

 

[jmb6420]

I’ve tried every option I can think of. If I start turning down sooner it seems to smother out the fire and I end up having to open it back up all the way to get my temps back up.

And yes my wood is dry. I’ve tried bigger splits , less splits. Right now I only fill up the box about half way or it gets away with itself. Still with half box of splits it gets to the point I sit and watch the floor temps surge and hold my breath until they settle back down.

 

[snobuilder]

I’ve tried every option I can think of. If I start turning down sooner it seems to smother out the fire and I end up having to open it back up all the way to get my temps back up.

And yes my wood is dry. I’ve tried bigger splits , less splits. Right now I only fill up the box about half way or it gets away with itself. Still with half box of splits it gets to the point I sit and watch the floor temps surge and hold my breath until they settle back down.

If you know where your secondary intakes are you could try a temporary control on them to see if that helps. A magnet large enough to cover or magnetic tape and a pc. of sheet metal.

 

[jmb6420]

If you know where your secondary intakes are you could try a temporary control on them to see if that helps. A magnet large enough to cover or magnetic tape and a pc. of sheet metal.

I’ve tried to find them and can’t. I think they are hidden behind the steel plate sides.

 

[Todd]

I’ve tried every option I can think of. If I start turning down sooner it seems to smother out the fire and I end up having to open it back up all the way to get my temps back up.

And yes my wood is dry. I’ve tried bigger splits , less splits. Right now I only fill up the box about half way or it gets away with itself. Still with half box of splits it gets to the point I sit and watch the floor temps surge and hold my breath until they settle back down.

Sometimes when I start shutting down it seems like the fire is going to die as the flue temps drop but it usually comes back after a few minutes or I just tweak the air up a smidge and give it a bit more time. Larger more drastic air adjustments can make you chase the fire and flue temps, sometimes a little patience is needed.

Have you checked for any leaks? Dollar bill test door seal? Do you have the ash pan? Could be leaky, does it run better with a full ash pan?

Another option is a pipe damper but first I would look for your dog house primary boost air if you have one. It should be located in the lower front center of fie box just below the door. Blocking this unregulated air sometimes helps slow down the burn, it worked for me.

 

[kennyp2339]

Its a pretty safe educated guess to say that stoves during certification testing are ran on high with the vacuum stack pushing between .05 - .08" wc. which mimics the average draft from a straight up 15ft stack.

 

[jmb6420]

No leaks. I've tested both the door and the ash pan. I can say that the last two fires have been better. I kept the flue temps below 700f. during startup and the the secondaries have been more controllable. On my old 1990 model Endeavor I liked to get the flue up to around 800f to keep it clean and get a more involved fire. Maybe on the newer models that isn't the best route to take. I'll continue to experiment and adapt.

I would like one of the more experienced people to answer the question "If the secondaries are in afterburner state with temperatures exceeding 800-850f, would a damper help lower these temps or would it just trap the heat in the stove making things worse?"

 

[jmb6420]

Its a pretty safe educated guess to say that stoves during certification testing are ran on high with the vacuum stack pushing between .05 - .08" wc. which mimics the average draft from a straight up 15ft stack.

I agree, I just can't believe Travis Industries was confused about my question on draft, also that they don't record or have any numbers on draft while testing.

 

[kennyp2339]

I would like one of the more experienced people to answer the question "If the secondaries are in afterburner state with temperatures exceeding 800-850f, would a damper help lower these temps or would it just trap the heat in the stove making things worse?"

A woodstove operates under a vacuum, adding a damper slows the flow and will have a direct relation of allowing how much air goes in, In order to proceed you need to test your draft and figure out what your reading is.

 

[kennyp2339]

I agree, I just can't believe Travis Industries was confused about my question on draft, also that they don't record or have any numbers on draft while testing.

They sure do, the question to ask is which independent testing lab certified the stove, then since its an epa record (government) you can look up the record and see what the parameters of the test was.

 

[jmb6420]

This is all @begreen fault. I was dumb, fat and happy running the stove for over a year until I decided to measure the flue temps. God only knows what some of my prior flue temps were last year when I was stuffing the stove full and running it 'normal'. Luckily the fan on this stove is wonderful and the STT never got too hot.

 

[jmb6420]

A woodstove operates under a vacuum, adding a damper slows the flow and will have a direct relation of allowing how much air goes in, In order to proceed you need to test your draft and figure out what your reading is.

I agree, which prompted me to ask Travis what the recommended draft was for this stove. Or, range of draft the stove operates best at.

 

[EbS-P]

No leaks. I've tested both the door and the ash pan. I can say that the last two fires have been better. I kept the flue temps below 700f. during startup and the the secondaries have been more controllable. On my old 1990 model Endeavor I liked to get the flue up to around 800f to keep it clean and get a more involved fire. Maybe on the newer models that isn't the best route to take. I'll continue to experiment and adapt.

I would like one of the more experienced people to answer the question "If the secondaries are in afterburner state with temperatures exceeding 800-850f, would a damper help lower these temps or would it just trap the heat in the stove making things worse?"

Damper reduces oxygen flow into stove leading to less combustion and less heat. It slows down the exhaust meaning it spends more time in the stove. More time for thermal transfer.

I’m getting better at judging draft on how the flames looks. On an average burn I get laze primary flames or almost no primary. Secondaries are more variable but I like to see flames wrapping around the exit holes in the beginning. At peak burn it’s more like a torch. My first stove just worked perfectly. Second stove on 24’ and was burning to hot for my liking.

 

[jmb6420]

Okay. I have completely changed how I burn now. I just had to adapt to the’ new’ style stoves. I no longer run the temps to 800+ on startup. I start shutting things down earlier and don’t let the startup flu temps get above 675-700. All my life I have got a roaring hot fire to ‘clear out the flu’ before shutting it down. That doesn’t apply to my 2020 EPA Endeavor. Short version “operator error or stubborn attitude”. I was expecting to burn the new style stove the same way I’d always burned. The problem was solved with the help of several suggestions here and me adapting to my stove. Who says you can’t teach an old dog new tricks!

 

[BrianVA]

Glad you got it figured out and thanks for the update. My understanding is that 850 F is not necessarily too hot, depending on where and how you were measuring. Though I imagine your burn times will be better with your new operating procedures.

 

[Caw]

Glad you got it figured out and thanks for the update. My understanding is that 850 F is not necessarily too hot, depending on where and how you were measuring. Though I imagine your burn times will be better with your new operating procedures.

850 F STT is defintely bordering on/or too hot for a modern steel stove. I have an Osburn 1600 steel stove and SBI defines overfire as 840 F.

I have good draft on a 24' chimney and regularly run it at 700 +/- 50 F STT at cruising. I only start to get nervous when I see 775 show up and I just hang with it until it settles. I've only accidentally 850 briefly twice since I've owned it and it was because I walked away and got distracted both times.

I'd love a flu probe but it's an insert and not really possible so I mostly run it with my eyes at this point. The STT gage is there as a back up and I'll zap it with my IR gun if need be.

 

[EbS-P]

850 F STT is defintely bordering on/or too hot for a modern steel stove. I have an Osburn 1600 steel stove and SBI defines overfire as 840 F.

I have good draft on a 24' chimney and regularly run it at 700 +/- 50 F STT at cruising. I only start to get nervous when I see 775 show up and I just hang with it until it settles. I've only accidentally 850 briefly twice since I've owned it and it was because I walked away and got distracted both times.

I'd love a flu probe but it's an insert and not really possible so I mostly run it with my eyes at this point. The STT gage is there as a back up and I'll zap it with my IR gun if need be.

You can do a probe with an insert. And a damper I want to be check draft with my magnahelic but that would need another hole.

 

[Caw]

You can do a probe with an insert. And a damper I want to be check draft with my magnahelic but that would need another hole.

View attachment 292333

I should have said "I don't really want to do it" instead of "not possible" lol. I've run enough wood through it and keep the flue clean to trust my burning practices. I don't want to put any holes in anything.

 

[jmb6420]

FYI: All my temps listed are flu temps 18” above the stove.

 

[BrianVA]

850 F STT is defintely bordering on/or too hot for a modern steel stove. I have an Osburn 1600 steel stove and SBI defines overfire as 840 F.

I have good draft on a 24' chimney and regularly run it at 700 +/- 50 F STT at cruising. I only start to get nervous when I see 775 show up and I just hang with it until it settles. I've only accidentally 850 briefly twice since I've owned it and it was because I walked away and got distracted both times.

I'd love a flu probe but it's an insert and not really possible so I mostly run it with my eyes at this point. The STT gage is there as a back up and I'll zap it with my IR gun if need be.

I agree 850 stove top would be too hot. But for probe measured flue temps, I've read 900 F (measured inside the pipe, 18" above the unit) is where you should start to be concerned.

What is a safe flue temp? What is too hot?

This question gets asked a lot. The first thing to clarify is - are we talking about reading the surface or probe temps? Single wall pipe gets a surface thermometer, double-wall connector stove pipe gets a probe thermometer. For either pipe you want to avoid continuous, temps over 900F. An...

www.hearth.com

 

[begreen]

Okay. I have completely changed how I burn now. I just had to adapt to the’ new’ style stoves. I no longer run the temps to 800+ on startup. I start shutting things down earlier and don’t let the startup flu temps get above 675-700. All my life I have got a roaring hot fire to ‘clear out the flu’ before shutting it down. That doesn’t apply to my 2020 EPA Endeavor. Short version “operator error or stubborn attitude”. I was expecting to burn the new style stove the same way I’d always burned. The problem was solved with the help of several suggestions here and me adapting to my stove. Who says you can’t teach an old dog new tricks!

Thanks for the update. I am glad you got it figured out and things have settled down. Like pappy used to say:
The most important nut is the one behind the wheel!