Drywall Temps behind your stove

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Woodspliter

Burning Hunk
Jan 25, 2020
204
Maine
So has anyone took the temperature of the wall behind their stove and the the stove pipe? I went with the minimum clearance plus like a inch or two the my drywall is getting pretty hot to the touch. I think I should cut it out and add an air gap and screw some 1/2 cement board. I have regular 2×4 studs and rock wool insulation behind the stove. Should I remove the insulation and let the wall breathe more? I'm running double wall pipe and took all the precautions
 
Define pretty hot. Can you hold your hand on it briefly? If so, how long. a micro second, one second, three seconds?
 
I exceed the minimum to double wall by about an inch and a half. I didn't like how hot the drywall got behind the pipe either. I just hung a 2' x 3' attractive piece of tin (with an airgap) behind the stove and all good.

mine was probably about a 3/4 second hand-hold max when I thought it felt pretty hot. Didn't have the ir gun at that point..
 
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Define even more? 160 is pretty hot and pushing what id be comfortable with. I'd be more concerned about the studs behind the drywall over time than the drywall itself.

I don't have a free stander but I do have a powdered steel hearth extender that gets quite hot, around 150 to 180 degrees, which is too hot for my liking. I added Micore underneath it to protect the hardwood floors. Those temps aren't going to damage the wood right away but exposure to those temps over time pyrolysis becomes a risk. Now the floor gets no hotter than 120 degrees which is perfectly safe.

I'd consider adding some protection to those areas or moving the stove further away if possible.

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It's hot! 160 on the infrared, behind the pipe even more
That's about the limit of my comfort zone. Our Castine gave similar readings even though the clearances were exceeded by several inches. It was a highly radiant stove. The corner install walls were hottest around stovetop level and maybe higher, Now, with the convective T6 in place, there is no issue, even though it's much larger.

Woodsplitter, what stove is installed?
 
So I was on a hot reload when I took the readings. Still trying to dail the new f55 in. I even installed a damper in the pipe right before the thimble. Even closed down it will cruise at 800 to 900 exhaust themp about 700 on stove top. Yeah it was pushing 200 behind pipe on the sheetrock a lot more than I'd like to admit

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200º on drywall is too hot. The stove is running hot. Try loading it tighter with large splits and smaller splits filling in the gaps. Also, close down the air sooner. This should slow down the burn and bring the temps down a little.

What is the stove connected to, a masonry chimney or stainless liner? How tall?
 
Yeah I'm trying to get the flueTemps down on reload. I have a masonry chimney the sove in the basement of my ranch house maybe 20ft or so. I thought the damper would have be the answer
 
Is there just a clay liner in the chimney? If so, do you know what the flue tile ID is?

Try shutting down the air as quickly as possible without smoldering the fire. That together with packing the fire tightly will slow down the rapid outgassing of the wood and the subsequent secondary bloom of fire.
 
First of all, congrats on the new stove and on having dry wood. That's a good start. The 8" interior flue is moving a larger volume of air which is creating a strong draft. A key damper will help tame this if the changing of operation does not achieve the desired result.

Is there a rear heatshield on the back of the stove? How are the temps being read? If using an IR thermometer, make sure it's in calibration. If the changes don't bring down the wall temperature to a more reasonable level, say 140º, then putting up a wall shield with a 1" gap behind it will make a major difference. This doesn't need to be cement board. It can be just a sheet of metal that can be painted, or even fancy made out of copper sheeting or the like.

If you have a chance, take a look at this video to see how temps respond on fire startup.
 
Try putting up a heat shield. There should be 1" minimum air gap behind the non combustible shield. The shield should have a 6" or so gap on the bottom (installed higher than the floor) and it shouldn't go as high as the ceiling.

iu
 
Yes, the shield would need to be on 1" non-combustible spacers. It can start at least 1" from the floor and reach to about a foot over the stovetop. It can go up the full length of the wall but must be open at least 1" at the top. This is to allow cool air to convect freely behind the shield.
 
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Try putting up a heat shield. There should be 1" minimum air gap behind the non combustible shield. The shield should have a 6" or so gap on the bottom (installed higher than the floor) and it shouldn't go as high as the ceiling.

iu
Agree with this. Gypsum takes much hotter temps to ignite/burn but the paper on drywall can brown from the heat. Still takes higher than 200 to ignite but having something like @yooperdave shows will give you piece of mind.
 
Agree with this. Gypsum takes much hotter temps to ignite/burn but the paper on drywall can brown from the heat. Still takes higher than 200 to ignite but having something like @yooperdave shows will give you piece of mind.
Over time the ignition temperature drops due to pyrolysis.
 
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Do they make a rear heat shield for that stove? We have a rear heat shield on our F500.
It's supposed to be integral to the stove but I was wondering if it got removed.
Part 9 22673392 - Rear Shroud, F 55 V2, MB
 
There is a collar shield for the base of the flue. I definitely need to address this issue I like sleeping at night. The heat shield is probably the most cost-effective solution. I'm thinking about ripping the sheetrock and putting up cement board with a air space and cladding it in fake brick
 
I'm just surprised that the damper that I put in didn't slow the burn down as much as I anticipated. Even closed off completely 20% it still pulled a good draft.
 
Ken Rajesky is quoted in a wiki link descdribing how stoves are tested for clearances

The benchmark temperature, which determines safe clearances, is typically 115 degrees F over the ambient room temperature. In other words, if the ambient room temperature is 70F, the benchmark wall temperature cannot exceed 185F. If temperatures exceed 185F, the stove must be located further away from the wall. That is why movable walls on tracks are used. If the temperatures exceed 185F, the walls are moved back until the temperatures recorded are less than 185F. In a nutshell, the stove is run through the complete test, the temperatures are recorded, and safe clearances are established.


Better to shoot for something a good amount lower and leave room for stove temps above the normal. The heat shield will do that. Yes, put up a proper shield and get that good night sleep. I was thinking cement board needed to be covered with tile but could well be wrong. If you would rather sheet steel a local shop should be able to cut you piece of maybe 22 ga and hem the edges pretty reasonably for that small area.

Funny thing, by the way, my new Etekcity infrared gun arrived and I used it for the first time today. It verified that my drywall temps were fine. Had the stove going good for a stretch tonight to keep the oven and pizza stone heating at 500. Wall temp still fine. Slick little device.
 
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Yeah I just have to get better at a hot reload I guess, right now on a cold start it's cruising at 400 stove top 500 flue temp.
 
I just hung my heat shield like you would a heavy picture (two screws and the shield just clips over them, so they are concealed).
 
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At a local deer hunting camp, the install had not met CTC. This included the single wall stove pipe.

Wanna know how it was addressed?


Nothing more than a length of aluminum foil hung behind the pipe and stove. Been like that for years! Would I do that in a house for full time burning? Ha! But, you can't argue with success; it works well and costs less than a buck! (see what I did there? Deer camp....less than a buck? Aw, forget it!)