double wall temp question?

[yamgrizz700]

Ok so i have black double wall stove pipe that i got from woodstock stove comp. and i was wondering what the temp should be when i am running the stove at around 500 or even up to 650 stove top?? even when i get the fire first going and really letting it fire up so to speak, it never gets or i don't let it get over 200 or 225.
when its cruising along the temp according the the thermometer is around 140 or 150. is that normal?? or do i have a draft issue?

 

[begreen]

Surface temps on double-wall are less than relevant. They make probe thermometers for double-wall pipe to measure the temp of the actual flue gases. However, there seems to be a bit of a problem with some recent probe thermometer accuracy. So for now, stick with the stove top temps and keep it below 650.

 

[yamgrizz700]

I was thinking about getting a stack thermometer, so i should wait? does it sound ok the way the temps are now when i am running and reloading?

 

[pen]

From everything I have found if you keep track of your stove top temps and keep under 650 as BeGreen said, then your flue will also be at the correct / safe temp.

pen

 

[yamgrizz700]

Ok thanks guys, is ther any reason to get the stove pipe hotter than the 225 250? and you mean stove top temp no greater than 650 right?

 

[begreen]

I never measured my double-wall surface temps until last week when someone posted concerns about this. I found the temp dropped off dramatically with distance from the stove. Probably best to just ignore it. Yes, try to keep the stove top below 650.

 

[yamgrizz700]

yeah thers not much heat that comes off the pipe near the thimble, thanks

 

[njburner]

I too am a new (late 2009) Fireview owner. Got my double wall stovepipe from Woodstock. All my pipe is the adjustable type: made installation a breeze.

I've had surface temperatures at 18" above the stove (measured with an IR digital thermometer) as high as 290F before I engage the cat. Once the cat is engaged, surface temperatures of the pipe drop quickly and dramatically.

Last night, for instance, I lit from a cold start, engaged the cat when stovetop was 250F, surface temp of double-wall stove pipe at 18" was 230F; about 10 min later, surface temp of stove was 300F and climbing, stove pipe surface had dropped to 180F. At reload, stovetop was about 370F, flue pipe surface at 18"was 170F. 8 mins after loading 3 splits, surface flue pipe temps at 18" had shot up to 280F; firebox was full of flames, all wood was completely charred on the surface, so I engaged the cat. Flue pipe was "ticking" (noise of metal heating rapidly), and there was a faint "sizzling/hissing" noise. Not sure what causes this, but it scares me so as soon as this happens I damp right down or engage the cat. 10 mins after engaging the cat, surface flue pipe temp at 18" had dropped to 200-210F.

As other folks on here have stated, you can't really say much about the *absolute* value of the temperature on the outside of the double wall pipe. But I reckon you can get a good feel for the normal range of values you can expect with your particular installation. With my setup, I have great draft if outside temps are in the 30sF or below. So even with my draft set low, I can get a lot of flames and heat going up the flue, and I have to be careful to damp down the draft.

I've bought a Condar flue probe thermometer because I wanted to check temperatures in the flue. To me, 290F on the surface of double wall stovepipe would mean a heck of a lot higher inside (1000F? certainly the cat glows red as soon as I engage it). But reading another thread on this forum, I see that there's a lot of doubt over the accuracy of these thermometers, and I'm wondering if I should go to the bother of installing it.

 

[yamgrizz700]

i have noticed similar noises and temps from my double wall stove pipe, as soon as my flue temp hits 300 or so its raging inside and i engage the cat, it makes me nervous to get the pipe any hotter than that,I have a 1856 cape, the stove is on the first floor and the thimble is close to the wall(Sheetrock wall) and the stove pipe is only 6" from the wall to the side of the pipe, just barley within code,hence why i needed double wall pipe. just a little off topic

 

[njburner]

Ah, glad it's not only me who is getting the sizzling I can hear it coming from the "joint" where two halves of adjustable pipe meet, about 30" above the stove. I'm not sure if I'm only hearing it because I'm using adjustable pipe (and everyone gets it but doesn't generally hear it), or if it indicates something sinister going on, like creosote about to fire off. As I say, I damp down or engage the cat as soon as I hear it; once the flue pipe surface temperature drops below about 250F at 18", I don't hear it any longer. I'm going to see if I still get it after I clean the chimney and stovepipe next week.

One of the reasons I recently got the digital IR thermometer was that I didn't trust the stovetop thermometers I got from Woodstock. I bought 2. Glad I did because one was completely useless: read 100F at room temp, read 100F an hour after lighting the stove. The other one changed temperature, but sloooooowly. Not nearly fast enough to capture the rapidly increasing/decreasing temps on the double-walled stovepipe. From what I read of the Condar flue thermometers, I don't think they'd react fast enough to capture the rapid flue pipe temp changes on reloads either. But I bought one because I want to make sure that my "cruising" flue temperature was within the recommended range. Based on the fact that surface temps of the double-walled pipe are approaching 300F before I engage the catalyst, I suspect I'm getting pretty high flue temps for short periods before engaging the catalyst.