Stove top vs. flue pipe Thermometer

[Cueman]

I have a double wall connector from the stove out the wall. I want to measure the flu gas temps to get an accurate read on the stove. Can you use the thermometer on the stove top for an accurate read? Or should it be on the pipe about 12" up as the instructions recommend? With double wall pipe, it is obviously much cooler and not a good read on flu gases. Is there a difference between the stove TOP and stove PIPE thermometer or is it basically the same, temp being temp regardless of location? Is it correct that the flu gases would be HOTTER than stove TOP readings?

Any advice? I don't think I want a fancy double wall pipe thermometer.

thanks

 

[pen]

You'll need a flue probe thermometer to measure the gasses of double wall pipe. A surface thermometer won't do diddly on double wall pipe.

Some people really like the probes as they read fast and can help you predict what your stove is going to do next. Others don't like drilling a hole through their double wall pipe.

pen

 

[Wyld Bill]

I got sick of messing around with the magnetic (not really) temperature sensors a couple years ago. I spent the money ($50 i think) for the stainless steel insertion type to put in the flu pipe. It works GREAT I have overheated before by leaving the ash door open but I just recalibated it & now it is fine.

 

[WES999]

Bottom line is that if you want to measure flue gas temp you need a device with the sensing probe INSIDE the pipe.

FYI on a cold start-up the flue gas temp (measured internally) can be 10 times the surface temp of double wall pipe. 1000 °F on the inside and just warm to the touch on the outside.

Actually the Condar flue temp probe is really just a bi-metal thermometer, with a steel rod to conduct heat form inside the flue, similar to the stove top model, not very fancy.

 

[Cueman]

Interesting replies. I've fired my new stove twice so far, and still in the break in period have kept it below 500 degrees as suggested by the Vermont Castings manual for the Encore. Maybe two more burns like this, then I will start to see what kind of real heat I can get out of this stove. One problem is my wood is not as seasoned as advertised by the guy who sold it to me. And when the magnetic stove top thermometer read 500, the stove was not really heating the house, just the direct vicinity of the stove was warm. I was thinking maybe the stove top reading was hotter than actual stove temp because of placement.

Are the flue gases hotter or cooler than the stove top right above the flames? Or similar?

I"m also considering removing the double wall connectors and replacing them with single wall. I have about 30" vertical to a 90 and 6" horizontal to the wall thimble. Am I not loosing some valuable heat exchange to the room with the double wall pipe being so cool. If I downgrade to single wall, that span of connector will increase my heat source to the house, no?

I had no choice but to go out the wall and go up class A the gable end, but I'm hoping that is not going to make the stove futile at heating the 1600sf of living space. For the investment of the whole deal, I'll be screwed if I cant turn the oil off when this stove is running.

any thoughts appreciated

 

[shawneyboy]

The heat lose is nominal the double wall helps with clearances, I am assuming you needed it for the install to be as close to the wall as you have it. That is the usual reasoning, if you change it out you are now risking home and life to gain some heat.

More accurately what is limiting your heating experience is the under seasoned wood.

Shawn

 

[firefighterjake]

I have a double wall connector from the stove out the wall. I want to measure the flu gas temps to get an accurate read on the stove. Can you use the thermometer on the stove top for an accurate read? No . . . only real way to get a somewhat accurate temp -- and I use that term loosely --is to go with a probe style thermometer or similar set up. Or should it be on the pipe about 12" up as the instructions recommend? Is it 12 inches . . . for some reason I was thinking it was 16 or 18 inches up from the stove collar . . . With double wall pipe, it is obviously much cooler and not a good read on flu gases. Is there a difference between the stove TOP and stove PIPE thermometer or is it basically the same, temp being temp regardless of location? The temps are quite different . . . especially if you're running your stove properly . . . heck, I guess there would be differences in temps even if you were running your stove incorrectly. Both the flue and stove top thermometer give you different info for different things -- the stove top temp lets you know if you're reaching overfire temps and gives you an idea of when you can cut back the air to engage the secondary or the cat . . . the flue thermometer lets you know if you're burning too cooly and producing excess creosote or if you're burning too hot and risking a fire danger. Both temps taken together can help you run the stove safer and more efficiently as they let you know what your stove is doing . . . and where it is going. Is it correct that the flu gases would be HOTTER than stove TOP readings? Depends . . . on the stage of burning and how you are running the stove.
Any advice? I don't think I want a fancy double wall pipe thermometer. Advice . . . I like . . strike that . . . love my Condar probe thermometer . . . and use it on every burn . . . just be aware that it is not a high tech 100% scientifically accurate device, but more like a gauge on your car that indicates if things are running too cool or too hot or just right . . . and they're very simple to install . . . a trained ape . . . or a dumb firefighter . . . which is about the same thing . . . could install one of these . . . not all that hard to install and most definitely not very fancy.
thanks

 

[firefighterjake]

Interesting replies. I've fired my new stove twice so far, and still in the break in period have kept it below 500 degrees as suggested by the Vermont Castings manual for the Encore. Maybe two more burns like this, then I will start to see what kind of real heat I can get out of this stove. One problem is my wood is not as seasoned as advertised by the guy who sold it to me. And when the magnetic stove top thermometer read 500, the stove was not really heating the house, just the direct vicinity of the stove was warm. I was thinking maybe the stove top reading was hotter than actual stove temp because of placement. Woodstoves are space heaters . . . and time dependent . . . if I started my woodstove up from a cold start and just let it die out I honestly wouldn't really warm the place up much . . . they really need some time to heat up the metal . . . and the surrounding environment.

Are the flue gases hotter or cooler than the stove top right above the flames? Or similar? Again, depends . . . I think it's safe to say that the temp in the firebox is almost always hotter than the temp in the stack . . . but the temp of the stove itself may or may not be as hot as the temp of the gases in the flue . . . there is a lot of mass and heat is being "pulled" from the metal . . . and it depends on where in the stage of burning you are talking . . . at start up my flue temp always rises faster and higher than the stove top temp . . . but once I have a secondary burn going the temp of the stove top is generally higher or at least equal to the temp in the stack.

I"m also considering removing the double wall connectors and replacing them with single wall. I have about 30" vertical to a 90 and 6" horizontal to the wall thimble. Am I not loosing some valuable heat exchange to the room with the double wall pipe being so cool. If I downgrade to single wall, that span of connector will increase my heat source to the house, no? Yes . . . but if you have a modern EPA stove the majority of the heat will be coming from the stove . . . this is where the bulk of the heat is generated . . . going to single wall can be done, but you're giving up some perks including the closer clearances.

I had no choice but to go out the wall and go up class A the gable end, but I'm hoping that is not going to make the stove futile at heating the 1600sf of living space. For the investment of the whole deal, I'll be screwed if I cant turn the oil off when this stove is running. If you sized the stove correctly you shouldn't have an issue due to the chimney or stove pipe . . . both Backwoods and I have Class A chimneys that go out and up . . . I cannot remember if Dennis' set up utilizes single wall or double wall . . . in my own case I have double wall . . . and heat a 1,800 square foot home . . . mostly with wood.
any thoughts appreciated