Proper GM 80 Temps.

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Bholloway22

New Member
Oct 30, 2022
4
New York
I have the green mountain 80 and cant find anything stating proper operating temps for both flue and stove top. I normally see stove top temps from 300 to 450 during a burn cycle. Highest stove top temp ive ever gotten to is 540. And flue temps measured with magnetic thermometer 18in above stove stay around 320 with cat engaged. Normally run on high until wood is charred nicely then back air down and it seems to idle around 400 for a few hours then I reload around 320 and repeat. Are my temps too low? Not much black glass, a little on corners but can get most of it to burn off. On a cold start up I can hear some cresote falling down chimney for a few min but stops once stop is uo to temp. Any help appreciated, 1st year wood burner trying to learn it's efficiency.
 
That sounds a bit low. How was the stove running at 540º? That sounds more normal.
 
That sounds a bit low. How was the stove running at 540º? That sounds more normal.
Seemed to be fine at 540, was just concerned with what my max normal temp should be with the soapstone lined cast iron stove. The heat output right now with my current burn cycle is a lot. My living room and upstairs are easily 80 degrees with stove top temps in the 350 - 400 range. Is that too low where I should be worried about creosote? Flue 18in above stove stays around 300.
 
It's a cat/hybrid stove so burning low is ok as long as the cat is active. What does the cat thermometer say?
 
If that is 300 on the flue, on the outside of single wall, then you're likely close to 600 inside, which I think is plenty high enough to avoid creosote - assuming your chimney setup is decent. I have the GM60 and my flue temps stay low, with a probe thermometer i'm usually around 400, but definitely spend some time closer to 300.
Stove Top Temp for me is similar, 350 to 500 through a typical cycle. With a full load at bed time when it's cold outside, i have gotten STT up to 650 briefly before. Personally i feel like 650 or 700 is the max, for brief periods. as long as it peaks around 650 and then starts coming down, i don't panic at all.
 
If that is 300 on the flue, on the outside of single wall, then you're likely close to 600 inside, which I think is plenty high enough to avoid creosote - assuming your chimney setup is decent. I have the GM60 and my flue temps stay low, with a probe thermometer i'm usually around 400, but definitely spend some time closer to 300.
Stove Top Temp for me is similar, 350 to 500 through a typical cycle. With a full load at bed time when it's cold outside, i have gotten STT up to 650 briefly before. Personally i feel like 650 or 700 is the max, for brief periods. as long as it peaks around 650 and then starts coming down, i don't panic at all.
yes, 300 on outside of the single wall 18in above stove. Chimney is about 14ft of single wall then double wall thru ceiling. Aprox. 24ft tall total straight out roof. Has a small offset in attic to go around a beam, but pretty much a straight shot up thru roof.
 
I think that would suggest 600 internal temp, which should be plenty high enough to avoid creosote. You just want to ensure you’re above 250 degrees at the coolest part of your chimney. If most of your chimney is inside the house and then class A afterwards, I think you’re good.
 
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I still don't understand that claim for the non-stone exterior stoves (gm series, Shelburne). Cast iron transfers heat quicker than stone, a 600 stone stt probably translates to 700+ or something if it's cast. If I load my stove full I pretty much can't keep the stt below 600. I've seen 700+ before. Haven't seen any signs of problems. Baffle looks good, etc.
 
I use a gun ir thermometer and tonight its 35 outside. My cat therm was right on the edge of active next to over fire and stt were reading 550 - 700 in different spots. Wish it was working like this the past few weeks temps were in the single digits. My cats were clogged. :(
 
Gm80 manual says inside range is 800 - 1300 deg F.
 
That sounds like the catalyst temp range.
While this statement is in the catalyst paragraph, the sentence says "The GM 80 operates between 800 to 1300 degrees. I've IR gunned a pile of coals and it pins my ir gun. When my stove is running and fully loaded STT 650F and almost pins my Cat thermometer (Still active range). So, I assume inside vs outside temps there's at least a 200 Deg difference.
 
Yes, they are referring to the catalyst temperature. Inside the firebox the temp could be 1000-1200º, but that is not measured on any stove.