Stove pipe thermometer comparison

[bigredgrizzly]

I've got 2 brand new stove thermometers on my stove pipe. Both read pipe temp, not flu temp. Which one would be more accurate? I've always used imperial but bought the sbi because it was $10 cheaper.

 

[begreen]

I'd be inclined to trust the SBI, but verification with an IR thermometer might say otherwise. Regardless, the flue temp is high.

 

[bigredgrizzly]

I'd be inclined to trust the SBI, but verification with an IR thermometer might say otherwise. Regardless, the flue temp is high.

Thanks! Never thought of an ir thermometer! You thi k the flue temps are high on the imperial guage?

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[Highbeam]

Odd but recently I’ve noticed that the temperature of the front of my single wall chimney runs 100 degrees cooler than the back at that 18” height. Fun with the ir temperature gun. Now I question whether both of your meters are accurate.

 

[bigredgrizzly]

Odd but recently I’ve noticed that the temperature of the front of my single wall chimney runs 100 degrees cooler than the back at that 18” height. Fun with the ir temperature gun. Now I question whether both of your meters are accurate.

Well damn! Haha

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[Grizzerbear]

Thanks! Never thought of an ir thermometer! You thi k the flue temps are high on the imperial guage?

You need a reading of flue gas in center of inside of pipe. Basically the rule of thumb i believe is that a magnetic stove thermometer is half of actual temp. So what your thermometer says is that your actual temp is around 800. Condar fluegar is what i use.

 

[mar13]

I have a collection of three stove top gauges, and they all differ some, even when on symmetric spots. (And I'm not about to get an i.r. gun to see which one is the winner.) Only one flue probe thermometer - thus nothing to compare with, so not knowing any better I just assume it's correct! (Actually, I figure everything is realitive to what the stove, the flames, and I are accustomed to in practice.)

 

[vwmike]

I check mine in the oven with a known accurate thermometer. My imperial was bang on at 400f

 

[Highbeam]

I check mine in the oven with a known accurate thermometer. My imperial was bang on at 400f

You would think this should work but it is not correct. The meters are calibrated to read the temperature of the surface they are stuck to while being in room temperature ambient air. Submersing the entire meter in hot air does not replicate the design intent and usually leads to high readings. A similar well intentioned mistake is submerging the meter in boiling water.

 

[Highbeam]

You need a reading of flue gas in center of inside of pipe. Basically the rule of thumb i believe is that a magnetic stove thermometer is half of actual temp. So what your thermometer says is that your actual temp is around 800. Condar fluegar is what i use.

The condar probe meter is designed and calibrated for use with double wall pipe where the outer wall shields the meter’s bimetallic coil from the pipes radiant heat. It’s a great meter, I own one, but it’s not for the single wall pipe. A surface meter is designed for single wall and it is less accurate than a probe meter in double wall.

 

[Grizzerbear]

The condar probe meter is designed and calibrated for use with double wall pipe where the outer wall shields the meter’s bimetallic coil from the pipes radiant heat. It’s a great meter, I own one, but it’s not for the single wall pipe. A surface meter is designed for single wall and it is less accurate than a probe meter in double wall.

Icic....i guess it was early and i assumed it was double wall...You are correct. Sorry for the misinformation.

 

[Grizzerbear]

I was way off base cause a magnetic thermo on double would probly read way less than half on double wall. I shouldnt post anything before noon lol

 

[begreen]

Wood gases swirl up the pipe which can cause one side of the pipe to be hotter and might explain the temp difference just a short distance apart. Swap their positions and see if they read differently.

This is why the multiplier for surface reading is just approximate. It could be half or two thirds the actual flue gas temp. I prefer a probe thermometer. It sticks out into the flue gas stream and provides a more accurate reading.