Stack Termometer Question

[ackerman75]

Anyone know what brand of thermometer is best for high stack temperatures,
I have tried a couple and they don't last with the high heat. Ebay has some with 1" to 4" long probes on the back of them, I guess you just drill a hole in your stack for the probe and fasten the thermometer some how ? they are rated for 2000 degrees. The ones I had fail only went to 900 degrees and fastened with a maganet. Thanks for any help in advance :)

[tapper]

This is the thermometer I use and quite often run stack tamps of 1600 degrees. I beleive I bought it from True Value hardware store.

[WESTVIRGINIAMAPLER]

Here's the link to the manufacture where you can also buy it I belive. I have the same one as Jon as he pointed me to them and I got them to order me one from a local stove & pool place. It's called a Flueguard thermometer:

http://www.condar.com/probe_meters_woodstoves.html

[dano2840]

Why do you need a thermometer on your stack? dont stop stoking the fire till the base stacks cherry!!!!!:D
i know a guy who has one and its the same as wvm is showing, it works well i would go w/ that
its pretty cool to see what your stack temp is when you fire and when it gets going and when you mess w/ the draft door.
i might put one on this year for the fun of it

[caseyssugarshack93]

I just keep stokin it and close the doors and let the stove pipe draft as goood as the ol girl can do.:D


nate

[Bucket Head]

I know some guys have installed an exhaust temp. sensor and gauge from a large diesel engined truck. Their called a pyrometer.

They scavenged them from old trucks so they were free.

Do you know of anyone who works on heavy trucks? Know of any heavy truck boneyards?

Steve

[WESTVIRGINIAMAPLER]

Don't know why I need a stack thermometer either, but I like watching it max out at 1700 degrees.

[Dennis H.]

I don't have one, Yet!

What I was told for the reason to have a stack themometer is that once yuo go above a certain point in temp all you are doing is blowing good heat out the stack that otherwise you could be using to boil with.

If memory serves me right it was last year up at the NY Maple Conf.
The guy mentioned something about it sure looks cool have flames shotting out the top of the stack but it is just a waste of good wood.

[tapper]

Dennis you have a very good point. I know in my case the hotter the stack temp the faster the sap dissapears although I would rather see that temp under my pans rather than up the stack. If my evaporator were 2 or 4 feet longer I probably would not see these temps. That is the drawback of a short evaporator.

[WESTVIRGINIAMAPLER]

When I run my stack temps around 1400 to 1500, I get less evaporation than I do at 1650 which is what it runs at most of the time. I don't seem to use any more wood at higher temps and it boils faster. I have plenty of wood, so I don't worry about that. My problem is time as I live 30 minutes away from sugarhouse, work full time job and have wife and 2 small kids. When I boil, I want it to boil as quick as possible.

[maple flats]

At the Verona maple conference this past weekend a guy from Leader was saying that the temp should be 800-1000 for wood fired and best is 900-950. He seemed to think that by watching the stack temp while you were setting your fueling interval you would maximize the efficiency of the evaporator. He did not say this would be the absolute fastest boil but that you would get the most gal/cord of evaporation. This would also have to be fairly close to max evaporation if not at it. As far as WVMer I can't answer why you get the fastest at a much higher temp. It might have something to do with your typew of evaporator. He might have been speaking of conventional type units.

[ackerman75]

Thank You Tapper And Westverginiamapler For Your Help An Valued Information. I Will Be Buying On Of These Thermometers And Firing Evaporator Acording To Temp :)
Thanks Again
Jamie

[RileySugarbush]

Think of high stack temps as if it was driving a car at full throttle all the time. You get where you are going faster, but at some addition cost in fuel/mile.

Time vs cost..... We all have different goals and make those choices every time we drive.

[Dennis H.]

Riley, excellant way to put it.

I want to have a thermometer on my stack but it would be used just for reference. I am like WV that I want it boiling as fast as possible, I have enough wood so that is not the issue. Now if I was using oil it might be a different story.

[markct]

so what happens to a galvanized stack at those temps? is it basicly the galvanizing is done and i just have a steel stack? just wondered cause my base stack and pipe is galv, it came with the evap so i used it, but the previous arch was a oil fired so wondering what to expect on the first firing

[mapleack]

I've been using a surface mount stack thermometer for years, and have found it more helpful the more I pay attention to it. One with a probe into the stack would be even better, and something I've been thinking about for a couple of years. There have been several mapletrader threads on the topic and this new one surfacing piqued my interest enough that I went online and found a digital readout EGT sensor and ordered it. $113 shipped for readout, case for the control and a probe. I'm always a sucker for gadgets, just wish it had a long enough cable to mount up front with the auto drawoff. As far as the discussion of reaching a point where you're wasting heat up the stack there's no doubt, but to really tell you'd have to be able to measure evaporation rate really really accurately and log that along with the stack temperature, graphing the result to see exactly where the peak evaporation to temperature correlation was. Also, as was pointed out, wood efficiency and evaporation rate efficiency are too different things. I don't want to waste wood per se, but I'm not in the business of staying up all night boiling either. I think that having a precise and quickly changing temp. reading will allow for fine tuning of the firing schedule for max efficiency.

[brookledge]

The same thing applies to oil or for that matter any fuel. You can crank up the fuel and the evaporation rate will increase but so will the fuel rate. And at a certain point you begin to loose eficiency by wasted heat up the stack.
Keith

[WESTVIRGINIAMAPLER]

I seem to be using pretty close to same amout of wood that I had when I had a blower that the cfm output was about a third of the one I have now. I hope to redo my arch in a year or two and inject air above and behind the fire to and see if that helps also. So if I am getting 10 to 15 gph more with close to same amount of wood, I would call it a big win. Now, I need a max flue pan to crank out about 100 gph on a 2x8. LOL Maybe with air injection above and behind I could get it to 110 gph.

[Uncle Tucker]

Brandon,
On the Proctor Maple Research site has a link to making a more efficient evaporator. There is a description for wood and oil. They say with wood you will gain “25-50% savings”. I would assume it is savings of wood scene you only fire once every15 to 25 minutes. Here is a link http://www.uvm.edu/~pmrc/Combustion.pdf

[danno]

Tucker - thanks for the link. Interesting read. I was thinking of putting air on top of the fire. So, they are saying point the nozzles slightly down into the fire?

Anybody have a design for "full air". I do better looking at schematics or at least a sketch.

[ackerman75]

Danno,
If you scroll to the very end of that link they do have a couple links although they are hard to make out. Hope this helps:)

[maple flats]

If you get max efficiency you should get the fastest boil possible. Over that is just putting heat into the stack that could not be used up under the pans. If fuel (any fuel type) is being burned after it exits the pan area it is totally wasted fuel.

[Amber Gold]

Does anyone know of other local sources for stack thermometers? I checked True Value and didn't have one.

Also where should the probe be mounted vertically...above the base stack? My base stack is 5' high. How is the thermometer attached to the stack? If it's 1/4" NPT would I just drill a 1/4" hole and screw it in?

[Mark-NH]

Aubuchon's sells them too.

[Amber Gold]

Mark, tried Aubuchon and they didn't carry one.

Called around to a bunch of places and can't find a store that carries them. A local stove shop can order one and have it in 2-3 days. I was hoping to get one for my boil tomorrow.

[WESTVIRGINIAMAPLER]

http://www.condar.com/probe_meters_woodstoves.html

This goes to 1800 degrees and I usually run mine from 1400 to 1650 degrees.

[Amber Gold]

Thanks Brandon. Ordered the same one yesterday.