A Little Test of Insert Temp Measurements

[BrotherBart]

For a while now I have been a little concerned with posts I see on the Forum where people take the operating temp measurements on the front of an insert. Back when I burned in an insert it wasn't an issue since with mine I had access to place a thermo on the top center of the stove. I have always known that the front of the stove runs cooler than the top plate but didn't say anything since I didn't have an quantitative info. Today we had a mountain of cardboard from some stuff we received and since my old insert is sitting out by the woods in the back I decided it was time to stick a stack in the top of it and play.

The long and short of it is that I fired Old Brownie, the 3/8" top plate, 1/4" side body insert, up to 846 degrees on the center of the top plate. At that temp the front of the stove above the doors measured 396 degrees.

Something to think about before you go looking to get that insert up to 600 or 700 degrees on a thermo stuck to the front of it.

 

[bluefrier]

very interesting because I plan on putting my condar medallion thermometer on the front of my stove instead of the top.
BB, I guess there was no other way to get rid of those cardboards hey?

 

[fossil]

Pretty interesting. I'm not surprised, though. All I use on my freestanders are magnetic stick-ons on the single wall just above the collars, so I'm looking at stovepipe temp very near the exit point (both top-exits). Obviously, I'm looking at temps 100's of degrees lower than the max temps in the firebox...maybe 1000 degrees lower...but I'm concerned not so much with overfiring but with keeping the temp up in a good range for limiting condensation of creosote. You did a good and interesting thing, BB...thanks for reporting the results of your testing for the benefit of the Forum. Rick

 

[BrotherBart]

BB, I guess there was no other way to get rid of those cardboards hey?

Could have hauled it to the landfill three miles away to be buried. Instead I fired the crap out of the old stove and the exhaust went clear within five minutes and stayed that way though the reloads. Love that old stove. If it hadn't of popped a weld after twenty years of 1000 degree burns it would still be in the fireplace.

The old gal's last fire two years ago this coming October.

 

[brooktrout]

very interesting post, BB. i am one of the accused :red: , routinely seeing temps top 750-800 on a door located therm. after carefully inspecting the stove this summer, i'm glad there is no damage. not to say that several years of such wouldn't, though. i don't think today's inserts could handle the extremes we have put our old classics through :coolgrin: .

 

[brooktrout]

By the way, it hink my rutland therm. is off- it has read 120 all summer long!

 

[JayD]

Why not build build a Bread and Pizza oven. Brick around it, build an oven on top were the flue exits ;-)

 

[BrotherBart]

Why not build build a Bread and Pizza oven. Brick around it, build an oven on top were the flue exits ;-)

Because it is already my redneck meat smoker.

 

[fossil]

By the way, it hink my rutland therm. is off- it has read 120 all summer long!

Is it one of the open-face magnetic deals? Tap it. If that does nothing, then try slightly bending the indicator needle out away from the face. If that does nothing, scrap it and get a new one. Rick

 

[fossil]

Why not build build a Bread and Pizza oven. Brick around it, build an oven on top were the flue exits ;-)

Because it is already my redneck meat smoker.

Also quite handy for quick disposal of documents that could be embarassing were they to fall into the wrong hands. Rick

 

[RedRanger]

That is a real eye-opening observation BB. I used to only be able to mount my thermomoter on the front door and assumed if I just added a hundred degrees it would be about right--not!! At least with the bear I mount it right on the top and believe it to be somewhat accurate by the fact the blower doesn`t come on till the temp reads 475 or so. Good on you for helping to take the guesswork out of the front mounts.

 

[Burd]

BB Good call on thr thermomoter. When I first started I asked were to put the thermo and most people said the center of the door. Well Im glad I didnt listen to them people. I was all ways told that heat rises so I put it on top of the insert near the stack.
Is there any other thermomoter out there besides the open face magnetic.Is there on out there that better then the rest?

 

[Hogwildz]

Good point BB. I have to say, with my PE baffle jetting the most extreme heat to the front of my insert just behind where I have both thermos. For me and this insert, I truly believe I am getting the best possible area for temp readings. This burn season I will try to get one on top, or vertical on the bottom of the liner and keep an eye on that. All I can say is my Summit is almost like on autopilot once up to temp. She likes running at avg to 600 degrees. If I shut her down below that, it doesn't get up to a steady temp and will drop way back down rather quickly. Like I said, I will move one thermo somewhere on top, most likely on the liner just above the collar, prolly the only place I can read it.

 

[BrotherBart]

Hog with that open shroud on the top of the Summit insert an infrared thermo should be able to get a reading both at the center of the top of the firebox and the stove collar too. Unless I am missing something in the pics of that insert.

I really used to cringe that first year when you were getting those 900 degree readings over the door. I was thinking cherry red flue collar. I would tend to think with the front exhaust exit on an EPA stove that it would be different. But the spread on the 30 is pretty much the same.

 

[karl]

Bart,

Since this thing has already popped a weld. Maybe one evening you could load it up with card board around dusk and get the door reading up to 500 or 600 and take a few pics to see if its glowing.

Also, that's not an EPA insert. Is it? I don't know how much difference that would make, but I would suspect some. To get your old stove up to 800 or so you would have to run it like blow torch. The new non cat stoves seem to really hold heat in the firebox itself. The top of the stove has metal, a shroud, an airspace that the exhaust goes through and gets reburnt, then a baffle, and finally a firebox. I'm going to guy an infared thermometer and see what temps I get and where I get them on the Summit this year. I'm just guessing the new ones don't have a 450 degree spread like you saw.

Also, cardboard is all heat and no coals. I bet a load of oak coals in the stove would read close 400 on the front and much less than that on top. Did you let this thing stablize or did you just burn the day lights out of it.

 

[BrotherBart]

Also, that's not an EPA insert. Is it? I don't know how much difference that would make, but I would suspect some.

Like I said, not much difference in the temp spread between the old stove and my new one.

Also, cardboard is all heat and no coals. I bet a load of oak coals in the stove would read close 400 on the front and much less than that on top. Did you let this thing stablize or did you just burn the day lights out of it.

Kept it rolling for an hour or so. But I have never seen any wood stove burning anything for any amount of time that was hotter on the face of it than on the top plate. Ain't gonna happen. The cooler air-wash is down the front of the inside of a EPA stove.

This was not intended to be the definitive work on stove temperatures, just a Sunday afternoon test of a theory. And hopefully the impetus for some of you guys with inserts to post some observations from your experiences this coming season. Gonna be a lot of new burners firing them up in a few weeks a lot of the "how do I measure temps on this insert" questions. There are every year.

As to loading it up to see it glow, been there and done that with it sitting in the fireplace loaded with hardwood. Twice and not on purpose. With the top glowing, the temp on top at 1185 degrees and the stove paint vaporizing the front of the stove was at 560 degrees. After those two adventures in one week it was retired.

 

[stanleyjohn]

More confusion!by reading this thread :-S Now it looks like ill need to research more to figure out the right temp when measuring at the top of the door.The four burns i did last march had a av temp of around 450 with a peak of 600.Since its a insert!no easy way to tell how hot at the colar without removing the surround.

 

[jbroich]

Very thought-provoking experiment. Sobering. Thank you.

 

[Hogwildz]

Hog with that open shroud on the top of the Summit insert an infrared thermo should be able to get a reading both at the center of the top of the firebox and the stove collar too. Unless I am missing something in the pics of that insert.

I really used to cringe that first year when you were getting those 900 degree readings over the door. I was thinking cherry red flue collar. I would tend to think with the front exhaust exit on an EPA stove that it would be different. But the spread on the 30 is pretty much the same.

Good point Bart, I have been digging holes for 2 weekends, my hands are spent, as is my mind. I didn't even think of an infared. Who has em on the cheap?
I can honestly say, even pre-door adjustment, when it hit 900, nothing including the collar was glowing at all. I did specifically look for that.
I can say I saw the inside of the baffle through the holes glowing inside the baffle a few times, but think this is prolly norm. Never the steel of the stove though.

 

[jqgs214]

I have the Mid size PE insert and average 650 cruising with a full load of hardwood with the thermometer just above door on right side. That is with the air totally closed. There is no way I can run it cooler without reducing the wood load drastically. I can put a thermometer front center top and will try when I fire it up, will be interesting. I dont feel like I have overfired my stove at all. My thermomter location is outside the glass wash flow and has no buffer beside the steel between it and the exhaust flames. With that distance to travel with the exhaust flame the top of the stove may not be its hottest point, but maybe. The exhaust gases are of course cooling as they leave the burn chamber but to what extent I have no idea. Curious to hear some responses to this thread this fall.