Flue Temps?

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Marshy said:
I agree, harbor freight has non-contact IR thermometers for $30. It would be worth the money to try and validate the mag thermometer.
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The new ones are different than the one I had but my HF one was utter junk. And it was back when they went on sale for $40 or something like that.

These seem like good deals for cheaper ones though, this is the one I got after I pitched the HF one https://www.amazon.com/dp/B00JCH2YJC/?tag=hearthamazon-20 it was under $20 and dual laser so you know how big your reading spot is (and its a very tight spot) wide range and different data modes, adjustable emissivity and all that.
 
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edyit said:
easy way to test the thermometer, set it in your oven see how close it comes to what you have your oven set at
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You would think so but no. The surface temperature meters are designed to measure the temperature of a surface while themselves being in cool ambient air. The bimetallic spring is a specific distance away from the surface. Putting it in an oven would indicate a false high. Also, ovens are notoriously inaccurate too.
 
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Ok. New update.

I turned the key damper about a quarter turn and things were going beautifully. Flue temps went up to about 450 at start up. Choked the air down, in increments, on the stove. Lazy flames on the wood, secondaries rolling. Stove top temps at 600 flue temps at 350. Yes! I figured it out! Turned the blower on and went upstairs. Went back down to check on things about an hour later and I am greeted with a dark firebox, no secondaries, no flame what so ever. Stove at 400 and flue at 200.

I think I'm just going to run it like I usually do since the consensus is that I'm really not doing any damage. I just thought I could get it to run more efficiently.

Thanks everyone for your help!


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Forgot to mention. Went by and picked up an IR thermometer and it is pretty spot on with the magnetic ones.


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You're over worrying it. You're doing no damage to the pipe IMO. And running hot is always safer in regards to a chimney fire than running cool.

[Hearth.com] Flue Temps? [Hearth.com] Flue Temps?
 
You bet. I've noticed that I have higher flue temps than most seem to report on here. I wonder if I'm reading it to low? I'm only about 12" from the collar, so when I next clean or mess with it I may move it up and see what difference I see? I get consistent good long burn times out of my stove so I haven't been worried about it.
 
Squisher said:
You bet. I've noticed that I have higher flue temps than most seem to report on here. I wonder if I'm reading it to low? I'm only about 12" from the collar, so when I next clean or mess with it I may move it up and see what difference I see? I get consistent good long burn times out of my stove so I haven't been worried about it.
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My thermometer is 18" from the collar and based from the IR readings there wasn't much difference from 18" on down. It did cool off above my damper though.


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Makes sense. I used to have a magnetic thermometer on this stove too and I found it didn't change much at all in the 12-18" range. I also use a IR gun to check/verify temps.
 
How are you loading the firebox? Can you take a shot with the next reload?
 
Squisher said:
You bet. I've noticed that I have higher flue temps than most seem to report on here. I wonder if I'm reading it to low? I'm only about 12" from the collar, so when I next clean or mess with it I may move it up and see what difference I see? I get consistent good long burn times out of my stove so I haven't been worried about it.
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That is a bit low, but setups vary. If there are elbows or offsets the flue gases slow down making for a hotter pipe sometimes.
 
That looks like a good N/S loading and secondary combustion shows up. Are you reading stove top temps with the blower on or off?
 
begreen said:
That looks like a good N/S loading and secondary combustion shows up. Are you reading stove top temps with the blower on or off?
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Both. The 400-450 flue pipe temps are with the blower on. It starts to settle down after about 2 hours. With no blower it easily gets over 500.


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Outside of the high surface flue temps all sounds pretty normal. Is this a straight up install or is there an elbow or offset above the thermometer?
 
begreen said:
Outside of the high surface flue temps all sounds pretty normal. Is this a straight up install or is there an elbow or offset above the thermometer?
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There is a 90 degree elbow about 3' from the collar. The thermometer is 18" from the collar. After you mentioned that elbows can slow the gasses down and cause higher temps I thought that may be part of the reason mine is so high.


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Could be. Is there a short section of horizontal pipe into the thimble that you could put the thermometer on as a comparison check?
 
begreen said:
Could be. Is there a short section of horizontal pipe into the thimble that you could put the thermometer on as a comparison check?
Click to expand...


Yes there is about a 4' section. When I checked it earlier with an IR thermometer, it was reading right around 425 At 18" from the collar it was reading 500.


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Interesting. My high temp readings are a little below my 90 too.


[Hearth.com] Flue Temps?
 
Quite a while back when pen was checking out thermometers I noticed this effect. There's a thread way back when somewhere that shows it.
 
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