Whats the hottest temp you have measured your wall at?

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.

barnaclebob

Feeling the Heat
Nov 29, 2017
315
Puget Sound
While learning to drive the stove this weekend we nearly fully loaded it a couple times to see what the burn times would be. In the middle of one of these burns I noticed the wall behind the stove pipe was very hot and got out my IR thermometer. The max temp I found was about 165F right behind the lower part of the double wall stove pipe. It was too hot to leave my hand there for more than a second or two. Would this temp worry you?

The stove is a progress hybrid installed to just above min clearances. Pipe is a selkirk double wall extendable sliding pipe. Stove top temp ( on metal just next to the pipe outlet) was about 575 and for sure never got hotter than 600. We were running it at the lowest air setting anytime it was above 400 at the stove top.

I searched for previous threads on the topic and the consensus was that as long as its installed to spec and doesn't go more than 115 above ambient (probably 80 degrees) then it was fine. There is no discoloration of the paint, burning smells, or anything like that.

Also I'm really glad I followed all codes and install directions as recommended by you guys. I used to think that they were likely overly conservative but after feeling how warm all of the surfaces in my house around the stove and hearth got, they are definitely not to be disregarded.
 
Last edited:
165 is hot enough for wood to undergo pyrolysis, causing it to become more and more of a fire risk over time at the same temperature. Make sure there's no wood (moulding/studs/etc) getting that hot.

If "the wall" is cement board on steel spacers, I wouldn't worry about 165. I am guessing that is what it is if you followed manufacturer's clearances and still have a 165 degree wall.
 
The wall must be catching radiant heat from the stove top. My double wall pipe you can hold your hand on. A picture of the setup and where you are measuring from may help with perspective...
 
Its a selkirk double wall pipe and I'm measuring from the wall to the closest point on the pipe. The pipe is at like 7" because the back of the stove has to be 6". The hottest spot on the wall is directly behind the stove pipe in the ~1ft section where the pipe isn't slid into itself. I'm pretty sure its radiation from the pipe. I definitely can't touch the pipe before it starts overlapping.

Pictures can be found in this thread: https://www.hearth.com/talk/threads/future-wood-burner-checking-in-progress-hybrid-install.165010/
 
  • Like
Reactions: Marshy
It was too hot to leave my hand there for more than a second or two. Would this temp worry you?
Yeow! I don't own an IR thermometer, I rely on my hand and if I can't leave my hand there indefinitely, I'm off to buy a metal shield and some sort of stand off. I just want to sleep comfortably at night.
 
Its a selkirk double wall pipe and I'm measuring from the wall to the closest point on the pipe. The pipe is at like 7" because the back of the stove has to be 6". The hottest spot on the wall is directly behind the stove pipe in the ~1ft section where the pipe isn't slid into itself. I'm pretty sure its radiation from the pipe. I definitely can't touch the pipe before it starts overlapping.

Pictures can be found in this thread: https://www.hearth.com/talk/threads/future-wood-burner-checking-in-progress-hybrid-install.165010/
Are you saying you have a 1' section where it is singlewall?
 
What's the minimum clearance to combustables for the back of stove? I know you said it complies but man that stove looks close to the wall...
 
If everything is up to code with the install and your still not happy with the heat on the wall, you can always build a wall shield, you def have the skills.
 
Yeah I was trying to see if there is any sheet metal artwork that would look good behind the stove. The other option is to stick a pipe shield on there like you would for a single wall pipe.

I might run it hard and monitor a few more times before deciding on anything. Its probably been run this hot and long 3 or 4 times now with no problems to the wall yet. I've read about the drywall degrading but its such a small area I'm not too concerned about that. Directly behind the stove was in the 140 to 150 range which felt hot but not worryingly so in my uneducated opinion.
 
My drywall made me nervous at 162°F.

Put up metal wall with spacers that I can hold hand on now, I sleep better now also.
 
90º over ambient is the threshold and it sounds like you are at or close to it. Concerns could be alleviated with shielding at the wall or perhaps at the flue connector.
 
Took me 1 hour. One inch space. Curtain has been removed.
 

Attachments

  • Whats the hottest temp you have measured your wall at?
    APS1100.JPG
    98 KB · Views: 252
barnaclebob, you stated that the pipe is "a selkirk double wall extendable sliding pipe." Please forgive a novice question but, is a portion of the pipe effectively single wall when extended? If so, could that be the source of the excessive heat?

Sent from my Pixel 2 using Tapatalk
 
No portion of the pipe is single wall, the sliding double wall pipes have two double walls sections that slide into each other. Regardless of its construction, its min spec distance to combustibles is 6 inches. Its at least 8" because the back of the stove is at 7.5 and the pipe is further than the back of the stove.

I'm aware that I can put up a shield of some kind but by the specs i shouldn't have to right? I'm curious as to how they determine the 6" rating because while my stove was cranking, it still had plenty of power to give.
 
By the specs you should not have to.

It's all about comfort level now.
 
Double-wall stove pipe still radiates considerable heat. Our rear-vent to vertical Castine install exceeded the clearance requirements by several inches and yet the wall (corner install) behind it still got over 150º. No issues with the Alderlea. Wall temp only goes up to about 130º. The back of the stove is well shielded and the stove is top vent.
 
Those more experienced will correct me if I’m wrong, but your clearnace needs to be measured from the drywall, not the studs behind the drywall. For the purpose of stove clearance, drywall is considered a combustable rather than a protected surface... i think...
 
The highest temp that I have measured is around 160 to 165 on the wall with my Progress Hybrid. Normally it is much cooler than that, but occasionally on a real cold winter day I run the stove hotter which increases the wall temp. At this point, I'm not worried, but installing an additional shield should definitely take care of the issue.
 
I've found that most manufacturers quote 117 degrees (F) above the ambient temperature for clearance testing. I've always been told that 185 + degrees is the tipping into the danger zone...