EBT Question.

I would think that flue temps would initially rise quicker, simply because during startup you are using dry kindling and giving the stove a lot of air (door crackers, damper open). Then, as the fire is built up with larger splits, the air would be cut back, the surface temp would rise, and the exhaust and surface temps would be brought in line with one another with the surface eventually leading the two. Or am I applying my armchair physics wrong.

I open the bypass feature on my stove during startup, so I have NO doubt that my flue temps (if measured) would GREATLY exceed the stove top until the bypass was closed and the wood began off-gassing. Again, this is my armchair physics.

Doesn't sound normal to me. Is your baffle snug up against the back of the fire box? Maybe that gasket back there isn't right?

Is there a certain flue temp you are trying to avoid hitting? Assuming the "50% higher" "rule" a flue temp of 500F on the mag would mean 750F inside. That's not out of line during start up, is it? Or am I totally clueless here?

spark if you didn,t know the exact stack temp,you probably wouldn,t be obsessing over it....seems to me your expecting your summit to perform the same way as your old stove,thats not going to happen,you know what your doing,just do it......

But what is "overfire" for a stack? UL 103 HT is rated to 2100F. I would expect to get up to 1000F for a brief period during a start up, easy.

Pagey said:

Is there a certain flue temp you are trying to avoid hitting? Assuming the "50% higher" "rule" a flue temp of 500F on the mag would mean 750F inside. That's not out of line during start up, is it? Or am I totally clueless here?

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No, that's been blown out of the water here with actual tests with the Condar probes, thermocouples, and external mag thermometers. It turned out that internal temps were roughly double external and even higher as temps rise. I'll find that thread.

https://www.hearth.com/econtent/index.php/forums/viewthread/51880/

Todd said:

Pagey said:

Is there a certain flue temp you are trying to avoid hitting? Assuming the "50% higher" "rule" a flue temp of 500F on the mag would mean 750F inside. That's not out of line during start up, is it? Or am I totally clueless here?

Click to expand...

No, that's been blown out of the water here with actual tests with the Condar probes, thermocouples, and external mag thermometers. It turned out that internal temps were roughly double external and even higher as temps rise. I'll find that thread.

https://www.hearth.com/econtent/index.php/forums/viewthread/51880/

Click to expand...

Ah I did not realize that. Tell you what. I vow here and now never to get a flue thermometer. I can see it now. No siree, Bob. I will not do that to myself. The stove settles in at 650F, and I can live with that.

Of course the temptation is now strong, just so I can have some numbers to offer to the discussion...

oldspark said:

Todd said:

Doesn't sound normal to me. Is your baffle snug up against the back of the fire box? Maybe that gasket back there isn't right?

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The stove is brand new but I had flames coming out of below the baffle in the back this morning.

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When it cools down check the baffle placement and disconnect that baffle, pull it out to check that gasket behind it. It could be leaking hot air up behind the baffle causing those high stack temps?

I'm even more lost after reading some of that other thread. It sounded like the Condar probe was reading too HIGH (i.e., the flue gases were actually COOLER than the probe indicated). Must.not.buy.probe.

Advice, if wanted?? No "flame" or insults intended. Deep six all temperature probes and look thru that nice big window, adjust primary air accordingly.

If you have to monitor the stack temp, and don't trust that your chimney can take 500 degrees, than I have to wonder how you can burn wood at all without stressing yourself out. I believe, as you have found, that if you think you are gonna get xxx stovetop temps without approaching that xxx initially in the flue, it ain't gonna happen. So if 500 is you max chimney temp, I would think that 350-500 is all you will get for the stove top. And yes at least 100 less with the blower, almost 200 lower with blower on max.

I actually think it is a good that you get the stack really hot on reload, just to keep the creosote from building up. How is the chimney been creosote wise with the temps you have been running?

oldspark said:

you do not want to "overfire" the stack either.

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How are we going to define that? How high is "high" when it comes to flue temps? And what are the consequences? Do any liners have a specified maximum allowable temp (other than the failure temp)?

I'm wondering if you are worried about high flue temps because you (or others) have experienced consequences related to them, or if you are worried about high flue temps because you have not experienced them this high with your old stove. A chimney fire is one thing, but in all the threads about overfiring the stove I haven't seen anyone talk about overfiring the stack. Have I missed something, or are we breaking new ground here?

I think the only way you are going to know if flue temps keep rising in lockstep with your stove top temps is to just go ahead and find out by running that stove up to speed with a full. You are speculating based on intuition. It is possible that once you get that stove up to temp that the flue temps will settle down. But I suppose you better resolve the question about the baffle first.

I would tend with branchburner on this: I would expect flue temps to be very high when starting up. Especially in my stove, as I bypass the baffle completely! Now, once the fire was cruising, I would expect them to drop and level off. I think we are breaking new ground here. It's certainly interesting.

Since I don't have a flue probe, I can't weigh in. But I would imagine that if I tried to control the initial flue temps during start up to over a "stack overfire," I'd smolder the fire really quickly.

Okay, I have to chime in here, but the only thing I swear to touch upon is that baffle gasket.

Spark, did you do the install? When I did mine, the baffle came seperate in a cardboard box. Upon getting it out of the box, the gasket was in there too and fell on the floor. I think that it would be very easy to overlook or not find it in the box, etc. Fortunately, I saw mine, saw where it went and put it together correctly. Plus, may have even been some instruction sheet in there that helped me out. If you did your own install, do you remember a gasket? If someone else did it, then who knows I guess.

BTW, I have found that PE is very helpful! I haven't visited with them about stove performance, but my blower came minus the air deflectors, and they sent them no questions asked. Well, I guess they did ask for my address.

Hope you get her figured out. I sure am loving my stove right now and can't wait for colder weather.

branchburner said:

oldspark said:

you do not want to "overfire" the stack either.

Click to expand...

How are we going to define that? How high is "high" when it comes to flue temps? And what are the consequences? Do any liners have a specified maximum allowable temp (other than the failure temp)?

I'm wondering if you are worried about high flue temps because you (or others) have experienced consequences related to them, or if you are worried about high flue temps because you have not experienced them this high with your old stove. A chimney fire is one thing, but in all the threads about overfiring the stove I haven't seen anyone talk about overfiring the stack. Have I missed something, or are we breaking new ground here?

I think the only way you are going to know if flue temps keep rising in lockstep with your stove top temps is to just go ahead and find out by running that stove up to speed with a full. You are speculating based on intuition. It is possible that once you get that stove up to temp that the flue temps will settle down. But I suppose you better resolve the question about the baffle first.

Click to expand...

I thought most liners were rated at a max 2100 degrees for a short time ala chimney fire, but also I think I've seen not to burn at continous temps over 1000? Now is that internal or external? So if the OP is already at a 500 external stack temp (which is according to my Condar mag thermometer the start of too hot) with only a 300 stove top I willing to bet the internal temps close to that 1000? I can see where someone would be worried, besides that sounds like an awful lot of heat wasted up the stack. Do the other Summit owners run that hot flue temps, don't think so?

Hot off the press! Spark your stove is ok... flue temps will vary as the cycle goes .... I get flames out of the back of mine as well .... I cut my air back when when I see secondaries, sometimes my stove isn't even at 200! Because its warming up... I got something from pe I will post in a few ... but I think your stove is fine.......
this is what i got from PE
they will be posting on the website soon i am told
hope this helps


PACIFIC ENERGY
FIREPLACE PRODUCTS LTD.
2975 Allenby Road
Duncan, BC, Canada, V9L 6V8


Use of flue temperature devices.
Q. I bought a flue temperature gauge, what should the temperature be while
operating the stove.
During the normal operation and burn cycle of your appliance flue temperatures will
fluctuate greatly. Flue temperatures will also fluctuate depending on the location of the
temperature gauge.
An adjustment to the draft control of your stove can take a significant amount of time
before affecting the flue temperatures.
The flue temperature can also be a reverse indicator of the desired operation of the stove.
i.e. you close the air control on the stove to cool the stove and the temperature on the flue
will rise, due to the reduced air flow.
As a result of the above issues many stove owners become frustrated trying to operate
their stove using a flue temperature gauge.
This is why our advice is to start the fire, load the first full load of fuel, set the air control
to a comfortable temperature for your self and forget it.

Ok, first off, those thermometers are merely for reference. Don't go by the temps and colored areas as gospel, or it will cause the frustration your having.
Thermos should only be used for reference. Its much easier to define how the stove is burning by merely judging by the load and how it is burning.
In my Summit, If I cut the air back at 300, it would die down and cool down exactly as you are describing. IMO that is way too low a temp to be cutting it back.
Try 400 to 500ish and you should see a drastic distance. But in time, you will rarely use the thermo.
From what I see, and I have seen and pointed this out many times, cutting air back too soon & too low a temp, and your wood may be not as dry as you think.
When you start burning a new stove, you must relearn how to burn in IT. Patience and the short relearn is all it takes.
Trying to compare a new stove and not knowing it well, to the old one it is replacing that you have been burning for years is ridiculous.
Be patient and take the time to learn the new stove and what she likes. If the old one was so great, you would not have the new one.
Good luck.

Old Spark - Based on my experience with our PE insert over the last 2 years, if you are cutting bakc the air, and your temp does not continue to rise, then you do not have a a strong enough fire going, and need to wait a bit longer before cutting the air back and try cutting it back in stages. Whne I cut my air back, with a strong fire going, the stove-top temp continues to rise, from maybe 400-500 up into the 800-900 range. i DO NOT MEASURE STACK TEMPS, AND AM NOT WORRIED ABOUT IT.

The best advice so far was to look in the window, and adjust air based on how the fire looks. If it starts to die too much, a few minhutes after you cut some air off, give it 15 more minutes of air, and then try cutting again, slowly. you should have good secondary burns, wit hthe ait cut off all the way, and this will raise the temps!

Come on you insert guys, I know if you could play with your flue temps you would. Your just jealous of us freestander guys because we have an extra toy to play with :lol: