New Stove, Long Burns, and How Hot is too Hot?

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audiolab1

New Member
Dec 9, 2012
8
My wife and I have been burning wood exclusively for heat going on 3 years now and we still consider ourselves newbies. Our original stove was an old Napoleon that was around 22 years old. We recently replaced the stove and the entire chimney with a PE Fusion and new double-wall stainless. I have noticed with the new stove, that we have had for about a month now, that fulling loading before going to bed usually results in higher (+800deg) flue temps than I would like to see, even with the damper fully closed. It seems that these newer non-cat EPA stoves all have an issue with not being able to be fully damped down. Now maybe I am just being paranoid with the flue temps, but what is the correct method and amount for achieving a long burn with these stoves? I am exclusively using large splits of hardwood that has been seasoned for 2+ years. Also, what would be the range of maximum safe flue and stove top temps for this stove (I have an infrared thermometer)? Unfortunately the manual says nothing, other than if things start to glow it's too hot. Duh!
 
After a reload or with a fresh start I will see close to those temps in the flue with our PE stove briefly until I close the air down. After turning the air down the flue temps drop to around 500F. You can reduce this happening by waiting to reload a little longer and closing the air down a bit sooner as the fire builds. As far as safety goes, you are within the rated temps for the pipe. Also note that some flue thermometers read high in the upper range by as much as 200F.

What's the total chimney height on the stove?
 
After a reload or with a fresh start I will see close to those temps in the flue with our PE stove briefly until I close the air down. After turning the air down the flue temps drop to around 500F. You can reduce this happening by waiting to reload a little longer and closing the air down a bit sooner as the fire builds. As far as safety goes, you are within the rated temps for the pipe. Also note that some flue thermometers read high in the upper range by as much as 200F.

What's the total chimney height on the stove?

I believe that the chimney is 18-20ft. I have got into the habit of turning the damper right down as soon as the flue temp reaches 550deg, this can still result in the temperature continuing to climb. I am also loading up the stove an hour before I plan to hit the hay in order to make sure that the temp is not continuing to rise. The first time I loaded the new stove up for an overnight burn I had to use the foil trick in the room air opening to stop the temp from rising past 800deg, and that was with the damper fully closed. I double checked that the ash flap is closed properly.
 
That is the same as our chimney. Is this with a Condar flue probe thermometer? How long does it stay at 800F?
 
How hot is the stove top when you reload?
 
That is the same as our chimney. Is this with a Condar flue probe thermometer? How long does it stay at 800F?

It's a Taylor probe that is probably the same vintage as the old stove (1990). It was at 800F for about 20mins. It was still climbing and that's when I stuffed the room air supply. I'm really worried that I'm not going to be able to load this thing up when it gets really cold.
 
Get an IR thermometer. They are accurate. You can get one from Harbor Freight cheap. I dont trust those mechanical thermometers.
 
Sounds like your probe is ready to be replaced.
 
Get an IR thermometer. They are accurate. You can get one from Harbor Freight cheap. I dont trust those mechanical thermometers.

That won't work for measuring flue gas temps in a double-wall connector pipe.
 
That won't work for measuring flue gas temps in a double-wall connector pipe.

I know it has been said that for single wall the internal is generally about 2x the external - is there a rule of thumb like this that is valid for double wall pipe?
 
I tried that with my IR thermometer and found that the surface temp varied radically with distance from the stove and even the side of the pipe the reading was taken on. It's not a method I would rely on unless I knew accurately how it correlated to the actual flue gas temps for that pipe setup and that the readings would be consistent.
 
Can't say for sure, but given it's age, that's very possible.

OK, since we are still quite new at this, who makes the best flue probe thermometer? I'd prefer something modern looking with black or silver markings. I can't stand the ones with yellow/orange/red range markers. That would look really stupid on our modern Fusion stainless!
I have noticed that to get the stove top temp up to 475-500F that the flue temp is hovering around 800F. I guess maybe I was being paranoid with it reaching that temp? All I know is that our old stove never reached those flue temps, but it was much smaller and likely far less efficient. Is there a quick primer on these forums that discuss things like ideal stove top temps, loading wood for long burns, etc.? This is a GREAT forum and I wish I had discovered it when we first started burning 3 years ago.
 
This is funny, you are worried about 800 internal temps, that aint nothing, good burning range. Did you have a surface or probe on the old stove?
 
This is funny, you are worried about 800 internal temps, that aint nothing, good burning range. Did you have a surface or probe on the old stove?

Like I said...newbie! I had the same probe on the old stove and if it read 600F the stove was cruising nicely, but it never peaked at much more than that. I have read comments that newer design non-cat stoves do tend to have higher flue gas temps, so maybe this is the difference. I was told by both the previous owners of the house/stove, and our licensed chimney sweep, that 400-600F was the ideal range for operation.
 
OK, since we are still quite new at this, who makes the best flue probe thermometer? I'd prefer something modern looking with black or silver markings. I can't stand the ones with yellow/orange/red range markers. That would look really stupid on our modern Fusion stainless!
I have noticed that to get the stove top temp up to 475-500F that the flue temp is hovering around 800F. I guess maybe I was being paranoid with it reaching that temp? All I know is that our old stove never reached those flue temps, but it was much smaller and likely far less efficient. Is there a quick primer on these forums that discuss things like ideal stove top temps, loading wood for long burns, etc.? This is a GREAT forum and I wish I had discovered it when we first started burning 3 years ago.

I just read over the sticky discussions regarding flue gas temperature probes and now I'm more confused than ever! Maybe just not worrying about it and going by the stove top temp with the IR is the best solution? Now, is 500-600F stove top a good cruising range for my PE Fusion? I can't understand why this kind of information would not be in the manual.
 
I was not making fun of you for being a newbie, its just I have hit 700 surface temp on my flue pipe with no problems what so ever, I usually keep it in the 500 to 600 range (surface,start up, reload), my old pre epa stove did run with a lower flue temp on start up and reload though, during the burn they are very similar.
 
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