How Accurate/Meaningful Are Flu Temperature Guage Readings ?

Bought a $15 flu temp gauge a while back . Its a magnetic dial thing with a spring.
Instruction on the package say the when you stick it to the flu you are reading a surface of the flu pipe temperature but that your internal flu gases are as much as 2 x the reading.
If I place it low near the stove - sometimes when really pushing it Ill see gauge readings spike up to 900 deg. This tells me that internal temps are as much as 1800.
Just read the other thread stating that halfway up/down is the best position.
Ive also read that the thickness and type of metal of your flu can also significantly affect the reading.

Im curious how many people really watch the gauge and make adjustments according to its readings.

I can always tell when my stove is in the groove. No smoke, no cherry red from overfire. etc.

keeping it in a consistant place will allow you to maintain a steady and effieient burn.

usually if the stack temp was 900ish and you turned the light off there should be a substantial red glow. this area if touched with the human hand, should cause smoke and tears as 900 is a overfire condition and touching it would prove that fact.....

900 seems really hot.

ShawninNY wrote:900 seems really hot.

i don't try to push it to 900 but I have thoughtlessly opened er up and walked away only to come back and see it glowing.

and I have accidentally touched that 900 metal... OUCH!

yes for sure prolly shouldnt touch it! actually much over 600 is getting into overfire zone.

best to get that heat to radiate off the stove instead of shooting up the pipe.

stack temp is indeed a meaningful reading and with it you can manage your fuel use!

yikes!! it turns the skin white instantly huh??? ask me how I know this!!

I use two, one placed in the pipe in front of the barometric and one at the chimney connector. This will let me have an idea of how efficient I'm burning. I use it a a rough gauge for operation. The hotter the stovepipe after the barometric draft regulator, the more heat wasted up the chimney. If the thermometer falls off the stovepipe, you are way too hot!

It also lets you know when your fire is ill and needs special attention.

coaledsweat wrote:It also lets you know when your fire is ill and needs special attention.

and 900F would def. be a *fever*

I found it useful for it to tell me if the fire deep down inside is still going. In other words it will read 100deg. most of the time during warm days when I idle it down real low. If it goes below 100 deg. The fire won't come back. Don't use it above that as I know what the fire is doing I can see and feel it's going strong.
I often open the door to check it and wonder if it's still going as it hasn't changed since adding coal 12 hrs earlier in the morning. It will idle so low now with the Pea Coal I'm using. This has been so nice. The other night I thought it was out. The temp gauge read 100 deg. but when I shook it it didn't throw any red glow or coals. I poked open a couple of holes from the top to find it and couldn't. But because the temp gauge read 100 deg. I left it set on my usual bedtime settings and in the morning I found it came back to a more normal fire.