Picked up an Englander NC30 today...

As is often said, it is not the prettiest stove, nor is it the longest burning, but it is a serious heater, that's for sure. And for the price, it is real hard to beat.

 

I've got a draft question here. This post may get long...

When I installed my liner and connected the tee snout to the stove pipe I didnt put any screws in it. The problem was I couldn't figure out how to squeeze screws in with the thimble in the way. I figured this wouldn't be an issue as long as I wasnt smacking the stove pipe around. Lately the stove has been acting strange. It was harder to control and the flue temps seemed way too high for the stove top temps I was running. I got to looking and discovered the stove pipe had slipped off of the snout. Fortunately the games were still exiting okay. My smoke detector and CO2 detector never picked anything up. Clearly this was not okay despite it's still pulling the gases out. Today I discovered I could pull the snout with the stove pipe adapter out just enough to drill some holes and put screws in. I feel much better about it now. Some pics...

Before...



After...



Now for my question...
I thought air getting in to the flue would slow the draft. It seemed to do the opposite in my situation. The flue temps are much more under control now as well. Does this make any sense? I would expect lower flue temps with air leaking in to the chimney.

Any ideas out there?

 

It should have...that is exactly how a barometric damper works, its basically a controlled/calibrated air leak that cools the chimney and slows the draft speed...

 

That's why I cant seem to wrap my head around what was going on. I'm at a loss.

I guess it doesnt really matter now that I got it all tightened up now. Just trying to figure out the 'why' to the situation...

 

Good you caught it!

 

Yes sir! Kinda scary whenever I saw that

 

There was obviously another contributing factor(s).

Did this temp variance happen over one day or several? May want write down what the outside conditions like, etc.?

Edit:
I may have an idea... maybe.

You originally said in your description, “Lately...” So here’s a question...

As of lately has the weather where you are located been colder than before “ lately”... before you noticed the pipe temp increase?

If so, have you been running you stove slightly warmer to compensate? I’m talking just before you noticed the pipe temp increase?

What was your stove top temperatures before AND after or when you noticed pipe temp increase?

Before you noticed the pipe temp increase what were your pipe temps recently before the spike, AND a few weeks ago?

You getting the opposite result might be able to be explained...maybe.

 

Pipe temps were continually pushing 1000-1100* (according to a condar fluegard) with stove top temps easily hitting 725-750*. If the STT got any higher than that I would close it down the whole way for a few minutes and let the temps come back down. I wasnt really counting on the flue temp gauge cause I'm not sure how accurate it is. It didnt matter what the weather was outside.

That's why it doesnt make any sense to me. Now that I have everything straightened out it is running great (that part makes sense). I would have thought my draft would have been killed with the pipe slipping off but it actually seemed like it was so much stronger (maybe less controllable is a better description).

 

Also the flue temp is so much more in line with the STT now (maybe the gauge is accurate after all). Before my flue temp was ALWAYS about 200-250* higher than my STT.

 

I’ve always wished I had the tools to monitor temps at the chimney outlet and even several locations within. I think with some stoves we might be surprised out outlet temps, though my thoughts could be way off.

What were stove top and pipe temps say the day or week before you noticed the spike? Do you recall?

Did the outside temps drop slightly as well? Enough to maybe warrant the stove running even a smidge hotter?

You running an mpd?

What are current STT’s and pipe temps?

 

I usually hit about 700* STT. When it was slipped off it would hit 750* without even trying. I know this stove can handle heat just fine. The problem was it was hitting 750* and more with the air all but shut down. Fortunately I was still able to close it off the whole way to cool it down when needed. The temps didn't bother me so much it was the fact that it would ramp way up like that really fast (from 200* STT to 750* STT within 10-15 minutes), run there for a bit and then drop like a rock about 2-3 hours later (to the 300* and below range). There was no gradual decrease in temp that kept putting out heat.

STT now are in the 650-700* range. They hang there for a while and then it slowly comes down over the burn cycle. Flue temps are usually about 75-100* higher than STT (according to a ventis flue probe which is a condar with a different paint job). I don't worry about it running away now unless I run it wide open.

Weather was actually colder last night than it was when it was harder to control. I had better control of it even with colder outside temperatures.

I'm not sure what you mean by mpd??

 

Manual pipe damper...
Stove might be able to take it, but those temps seem excessive to me for a normal burn rate... talking about letting stove get that hot before closing her down to cruise. Doesn’t matter to me how you run your stove, but if it drops to 300ish gradually, unless you really need the extra heat, you could save your fuel for longer burn... not necessarily a low burn, but a sustained household temperature. Of course, I don’t know your situation and I’m not sure where you live or how cold it is or has been lately. It’s been warm here. However, I am a bit concerned you, and many others, don’t give yourself enough of a cushion in the event something happens. Good thing you was home... and of course had you not been home my concerns wouldn’t matter.

You running a pipe damper? If so, did you try to close it or open it? I realize it didn’t matter and you witnessed an opposite effect of what you expected with the leak.

Give me a second...I’ll be right back

 

I’m going to go way out on a limb here and my intent is only to share some thoughts. I may not be right, but I think I could be on to something. I had a similar incident last year...but I had no leak, but another factor we can discuss later if you want.

I’m thinking the leak was causing a little secondary combustion in the stove pipe which caused the temperatures to spike and the draft to pull harder.

That is the opposite effect you had thought, right? I’ll try and explain after you reply answering the last couple questions. For now think of this...

...some older American stoves, and many current stoves made in the UK and Europe have primary controls down low and secondary air controls up high. When the stove reached operating temps, primary’s could be nearly closed and secondaries opened...for multiple fuels...for secondary combustion. Sounds way out on that limb I know because we’re talking about the top of a wall thimble connection. Lol!

If you could answer the last few questions in this post and the last it would be helpful.

Whether my thoughts on secondary action in the pipe is right or not doesn’t really matter. What matters is the leak had the opposite effect most of us may have expected. The question is: why? I think I might be able to explain it.

 

Ok I gotcha. Yes I have a manual pipe damper installed. I rarely use it. I have it there as an emergency brake just in case. I did have to use it the other night though due to the high winds we had here.

You very well may be right as far as some combustion happening in the pipe. I'm open to all suggestions here cause I cant explain it.

In the end though this is really only to try and satisfy my curiosity.

 

I agree with Hoytman. I think you were getting a secondary burn in the pipe due to oxygen injection. If the leak was bigger it would have killed your draft, but the small crack acted like a jet in a carburetor.

 

I don't think there is enough "fuel" left in the exhaust of a properly run EPA stove to support secondary combustion in the flue...and by the white/grey soot in Marvin s pipe, I think it is being run properly.
Now if this was an old school stove, I'd say this theory would be more likely.
Got to go back to basics, the old fire triangle, fuel, oxygen, heat...and we only have two...(IMO)

 

I wasn’t implying he wasn’t running his stove properly. I was implying that those temps are precisely approaching high enough to ignite any residual smoke/fuel left in the pipe...whether he was using a damper or not. In this case, damper open or closed wouldn’t seem to matter. What may have mattered was the injection of oxygen on an already hot stove/pipe unit.

Something caused the spike. Only three things it could have been. The “triangle”...heat, oxygen, and fuel.

The pipe connection, where the leak happened, was above thermometer. If there is ignition above there it would seem to make sense that the draft would pull harder causing the stove to spike as well...explaining the visual known...the thermometer spike.

What is harder to explain, brenndatomu, is if you are correct that only two in the “triangle” may have existed. I can’t help there because I’m my mind I can’t make sense of the results of what happened. Then to me the leak should resulted in the opposite as the two of you mentioned earlier.Neither is a big deal, but it’s fun to think about and discuss.

 

The two comments about how a barometric damper are precisely how I used to look at how a barrow works until recently. Those two comments are NOT wrong, but they only describe part of the story and when you wrap your head around this you’ll better understand how I think oxygen injection caused even a tiny bit of smoke to ignite into secondary combustion...even just a small amount of smoke leaving the stove.

A baro’s primary function isn’t always to allow room air to cool a pipe and slow the draft...that is just a byproduct of how it functions. It also describes only one use of a baro...taming too much draft. It’s function are more than one scenario.

Let’s keep it simple...

Air controls on the stove work on air coming in the stove.

A damper works on air leaving the stove and/or keeping heat in the stove.

A baro’s primary function works on the chimney side of things; like too much excessive draft, and air or pressure changing in the chimney...from the top of the chimney to the baro. Think of it as air moving across the top of the chimney or coming down the chimney...and/or changing pressure inside or outside the chimney. A baro works by reacting to these changes before they reach an mpd or before they reach a stove...even when/if the changes are sustained for a while.

That’s a minimalist description of each of these doing their job on their own. As the stove heats up to the working temps we want these controls take on working together, at the same time, and each together gets a little more complicated. It becomes too much to worry about for this conversation.

Marvin apparently had none of these “baro type” changes or effectively the temps would have dropped as some thought they should have...just from a leak in the pipe. I even reached the same conclusion at first thought.

So, why did the opposite take place?
Heat...even a tiny bit of smoke...and air injection is the only way I can make sense of it. Had to have the heat though...without the stove already being run at high temperature it is likely it may not have happened.

 

We will most likely never know for sure...but going back to the fire triangle...say we do have a small amount of fuel, (smoke) it still has to be in the flammability range, as far as air/fuel ratio. To lean...(not enough fuel, or smoke)...no fire. To rich...(too much fuel, or smoke)...no fire. And again, looking at that pipe, I'm saying that NC30 is running too clean (lean) to pull this off...again, IMO.

 

Yeah...probably will never know...

I agree with most of what you just said, brenndatomu. It seems it may have been perfect. It’s still a maybe scenario. As far as the stove running too clean...I can’t say for sure if too clean was clean enough to prevent any left over particles from igniting.