Importance of Thermometer...

[firefighterjake]

I watch my flue temps more than anything else. When she's cruising along in the 250-300 range I know my stove is operating efficiently and not sending too much wasted heat up the stack.

I was wondering about flue temp, does any one else do this and use the 250-300 range as a effieient burn range?

Yup . . . I would guess that when it comes to temps and monitoring the temps about 95% of the time I am running the stove with the flue temps . . . although in my case I'm most happy when the temps are 500-700 degrees since this is right in the middle of the 400-800 degree safe range on my probe thermometer (due to the double wall pipe). I tend to use this thermometer most often for determining when to start shutting the air control . . .

I still have the thermometer for the stove top, but since I added the soapstone topper I know it's not as accurate . . . it seems to show about 100 degrees less than the actual stove top temp . . . based on the readings from the IR thermometer . . . but of course that varies depending on if its reading from a cold start before the stone has had a chance to heat up or if it's been sitting there for quite some time.

 

[Battenkiller]

I watch my flue temps more than anything else. When she's cruising along in the 250-300 range I know my stove is operating efficiently and not sending too much wasted heat up the stack.

I was wondering about flue temp, does any one else do this and use the 250-300 range as a effieient burn range?

Flue temp is all important to me, stove temp is merely academic. Flue temp tells me how my burn is going, the stove temp tells me how much heat the stove is putting out. I can just stand next to it to tell me that.

Todd finds his cat stove burns best at 250-300ºF. On my stove, 350-400º on the single-walled pipe 18" above the collar is a perfect, clean burn. Stove top temp can vary all over the place with this same flue temp, but the stove doesn't cruise smoke-free at flue temps below 250º until the tail end of the burn, when all that's left are coals and flue temps naturally drop.

Another thing to consider is that draft is almost directly proportional to flue temp over the normal range of stove use. That means that higher flue temps make the stove draw harder. That may spill more heat into the outdoors (call it "the angels' share"), but when I want to get all the heat I can out of the stove, I need more air pulled into the stove. Only higher flue temps will do that with any given flue.

I don't count heat that goes up the chimney as a loss in burn efficiency. On many stoves, it's quite possible to have flue temps in the 250-300º range and be spewing smoke out the top of the stack (extremely inefficient). As long as I am burning clean, I live with whatever heat goes up the pipe. With a clean burn, the net efficiency of the entire system will produce more sensible heat in the living space for a given mass of wood. That's the only efficiency that matters to me.

 

[firefighterjake]

I was wondering about what everyone else runs their flue gas temps also. I just ordered a condar fluegard thermometer that installs inside the stove pipe. According to the directions the probe should be installed at least 18 inchs above the stove top and the flue gas temps measured by this thermometer on single wall pipe is approximately 50% higher than temps shown on stove pipe surface thermometers. The directions state that 400-900 degrees fahrenheit is the best operating flue temps for the most efficient wood burning without creating excessive smoke and creosote. It also states that a flue gas temp of 400 degrees or lower equals incomplete combustion , causing soot, smoke, and hazardous creosote . Resulting in clogging of combustors in catalytic wood stoves.

Is anyone else running this condar probe and what range are you running your flue gas temps in order to achive a good burn and prevent creosote build up?
I'm installing mine on double wall stove pipe and plan on keeping it in the 400 -500 degree range then inspect the chimney after burning at least a cord of wood , then go from there.

Yes . . . I too have a Condar probe thermometer. I can't guarantee that it is spot on for temps . . . other folks here have done some tests which may indicate it is not highly accurate, but I can say that my regular Condar thermometer has been very accurate when compared to the IR thermometer readings.

As you said the "safe" zone is 400-900 degrees . . . but realizing that the accuracy of this thermometer (and most others) may be suspect I tend to run the stove with the temps in the 500-700 degree range . . . and so far these temps combined with well seasoned wood has resulted in a minimal amount of creosote build up (although I still check and sweep every month.)

You can certainly keep the flue temps at 400-500 degrees . . . but as I said, I prefer to go a bit higher with my temps.

 

[NH_Wood]

I was wondering about what everyone else runs their flue gas temps also. I just ordered a condar fluegard thermometer that installs inside the stove pipe. According to the directions the probe should be installed at least 18 inchs above the stove top and the flue gas temps measured by this thermometer on single wall pipe is approximately 50% higher than temps shown on stove pipe surface thermometers. The directions state that 400-900 degrees fahrenheit is the best operating flue temps for the most efficient wood burning without creating excessive smoke and creosote. It also states that a flue gas temp of 400 degrees or lower equals incomplete combustion , causing soot, smoke, and hazardous creosote . Resulting in clogging of combustors in catalytic wood stoves.

Is anyone else running this condar probe and what range are you running your flue gas temps in order to achive a good burn and prevent creosote build up?
I'm installing mine on double wall stove pipe and plan on keeping it in the 400 -500 degree range then inspect the chimney after burning at least a cord of wood , then go from there.

I have the Condar on single wall pipe at about 18" above the collar. When the stove is cruising, I'm typically at 600-700deg. Seems to be the sweet spot when everything is good (good wood, good draft, etc.). Cheers!

 

[Backwoods Savage]

No probe here; just a thermometer stuck on the top of the flue which runs horizontal. We take it up to 500 on reloads and when we turn the draft down and the cat on it will drop to the 250-300 range. Sometimes just a bit higher, maybe 325. Works good for us but some stoves need a higher temperature to burn good.

 

[Todd]

I was wondering about what everyone else runs their flue gas temps also. I just ordered a condar fluegard thermometer that installs inside the stove pipe. According to the directions the probe should be installed at least 18 inchs above the stove top and the flue gas temps measured by this thermometer on single wall pipe is approximately 50% higher than temps shown on stove pipe surface thermometers. The directions state that 400-900 degrees fahrenheit is the best operating flue temps for the most efficient wood burning without creating excessive smoke and creosote. It also states that a flue gas temp of 400 degrees or lower equals incomplete combustion , causing soot, smoke, and hazardous creosote . Resulting in clogging of combustors in catalytic wood stoves.

Is anyone else running this condar probe and what range are you running your flue gas temps in order to achive a good burn and prevent creosote build up?
I'm installing mine on double wall stove pipe and plan on keeping it in the 400 -500 degree range then inspect the chimney after burning at least a cord of wood , then go from there.

Yes . . . I too have a Condar probe thermometer. I can't guarantee that it is spot on for temps . . . other folks here have done some tests which may indicate it is not highly accurate, but I can say that my regular Condar thermometer has been very accurate when compared to the IR thermometer readings.

As you said the "safe" zone is 400-900 degrees . . . but realizing that the accuracy of this thermometer (and most others) may be suspect I tend to run the stove with the temps in the 500-700 degree range . . . and so far these temps combined with well seasoned wood has resulted in a minimal amount of creosote build up (although I still check and sweep every month.)

You can certainly keep the flue temps at 400-500 degrees . . . but as I said, I prefer to go a bit higher with my temps.

Yeah, those test pretty much confirmed what I thought, that they are more calibrated for double wall pipe and can read over double the external pipe temps of single wall, not the 50% they claim. If you have single wall I suggest a magnetic external thermometer.

 

[bigealta]

Thermometer .........Defiantly

You can't tell the difference between 500F and 900F at 2 feet above the stove on the single wall pipe unless you see the therm. Not at my house with the jotul3. If you are running on "feel" your just wild guessing.