The wall gets hot!

[jason1238]

Hey all,

I am beginning to get concerned about how hot the wall behind my stove is getting. I've got 45" up from the floor that is ceramic tile over poured concrete, and then stud wall with drywall the rest of the way up (total ceiling of about 7'6"). The tile stays quite cool, but the drywall gets almost too hot to touch. I'm sure it's the heat radiating from the black pipe causing it, but I've got 14" of clearance from the pipe to the wall. The pipe is ICC double-wall, so according to the manual: (broken link removed) (my install is exactly like the "90 degree elbow" install on page 6),
...I have over double the safe clearance, right? I know the "too hot to touch" thing is very objective, but I don't have a way to check the temp exactly.

At what temp (I'm going to buy an IR temp gun) should I start to worry? How hot can drywall get before it lights off?

The room with the stove running about half-throttle, stays 80-85 degrees, and the heat moves around the house nicely, but it's getting harder to sleep at night thinking about this...

Any advice would be appreciated.

Thanks,
-jason

 

[beagler]

I believe I read somewhere that dry wall will ignite at 451 degrees F. Dont take my work though. There are many professionals around here that will know for sure. Stay warm this weekend.

 

[eernest4]

If you are actually worried enough about it to do something , here is one option.

Buy a 2 ft x 8 ft section of sheet metal roofing panel for $8 to $12 , around that price, I forget
exactly what it costs, as a heat shield for the drywall.

It can be mounted on 1 inch standoffs which you can make from a section of alluminum tube & a hacksaw . You can buy a length of aluminum tub or plastic tube from the electrical dept at home depot or lowes. Or you could use electrical tubing connector sleves, if they are the right length for you. You need to look some in the electrical dept @ above stores.

The sheet metal roofing panel can be cut to your desired size with tin snips or another section can be added on , as required.

The heat shied is mounted 1 inch off the wall with air space under it so that cooling air can flow behind it. Use fine drywall screws through the center of the standoff's to mount it.

You will have to drill 1/8 in mounting holes through the sheet metal , but it drills easy with a sharp metal bit. Won't drill at all with a cheap wood bit.

This is an option, ( you don't need to take it ,unelse you like it.)
availble to you with only a little money & a little work. The final choice is yours.

Might be a better way to skin this cat. I don't know.

I been thinking about doing the same for my stove.

You can paint the heat shild to match your room's decore, but use a high heat paint.

I'm not altogether sure if I am going to put one up in my house as I just bought a summersheat Model 50-snc30lc @ lowes for $476.oo -1/2 price sale, reg $1100.oo & it comes with a rear heat shield installed on the stove.

summersheat is the low price version of the 2000 sq ft www.englanderstove.com -- stove that so many people rave
about here, so I am highly looking forward to getting it insatalled.

Best of luck in your endevors.

 

[derbygreg]

http://www.sandhillwholesale.com/ad...board&osCsid=29fa5d494a140bd749e11497afaf4ab6

check out the stove board, it is made specifically for your problem. Get the spacers too. It will look good too.

 

[thechimneysweep]

Hey Jason,

Sheetrock is covered with paper, and there are two ignition points for paper:

Piloted ignition point (the temperature at which paper will ignite with an open flame) is approximately 451 degrees f

Spontaneous ignition point (the temperature at which paper will ignite in the absence of flame) is considerably higher.

The wall behind your stovepipe might feel hot to the touch, but I'm betting it doesn't raise a blister, as would happen if you plunged your hand into boiling water. Water boils at 212 degrees f, so you know your wall is no hotter than 212f (if you can hold your hand on it, it is probably no hotter than 150f).

Which means it can't possibly ignite, even if you touch it briefly with a lit match (I say briefly, because prolonged direct contact with the open flame would eventually heat the paper to 451).

Prior to ignition, a given material can't get hotter than the source of heat. Suspend a meat thermometer in a pan of boiling water, and no matter how long you boil it, it won't register over 212. So, the wall behind your stovepipe can't get hotter than the outer surface of the pipe.

Try this: stick a stovepipe thermometer on the outside surface of your pipe at the point where it extends above the tiles. How hot does it get?

 

[swestall]

First, if you have access to an IR gun, find out what the temp is. If you have double wall pipe, your clearance sounds fine. Is this a corner, and is the heat from the stove rising and heating the wall? Understanding the amount of heat with the IR gun will tell you alot.
If you need the look, you can finish this with backer board, durarock and paint it just like it was a wall. BUT, you might not have a problem, just a warm wall.
You have to do the work to define the problem, exactly, the address the situation as it turns out to be.
When that's done, you will sleep well...

 

[begreen]

It seems odd that double wall pipe would be radiating that much heat. Mine is roughly the same distance from drywall and the wall is just warm to the touch. I can actually touch the pipe itself quickly.

Do you have a flue thermometer or stovetop thermometer? What temps are you running the 3100 at?

 

[Heartwood]

I had this concern (also have double wall) and after reviewing threads on the subject, called my mfr. He made me feel alot better saying drywal is safe to 160-180 degrees f. At first that didn't sound too encouraging, but he said to remember that the hot water coming out of my faucet is probably 130 deg, and I can't hold my hand under it. I can at least hold my hand on the drywall, so that in itself tells me I'm well below 160. Been burning hot like that now for three months and all is well.

Bear in mind though that it's a good idea to be sure of the max temp it gets to. I've read in researching posts here that even though some materials may not have yet combusted, there is often a temp at which their flash point will be reduced. I'm no expert on that, just know I read it.

 

[jason1238]

Thank you all. You have eased my concern, but I'm still going to get the IR thermometer and check it out for sure. I think my neighbor a couple doors down (also a woodburner) has one...

I guess it makes sense that the wall temp can't be much hotter than 160degrees. After all, I can hold my hand on it for a second or so, and I'm surely not blistered after doing that.

I work with sheet metal for a living...would it be OK to fab up a shield for the pipe? I'm thinking something that mimicks the outer radius of the pipe, and stands off of it about an inch. It would only wrap a little less than half way around the pipe, and would be a whole lot easier to color match with high temp paint (in black) than a wall shield (in a "maroon" color according to my wife). Do they even make high temp in "maroon"?

It might even throw a bit more heat into the room...

Thanks again to you all!

-jason

 

[begreen]

I think you will find the wall temp at 130 or less. Please check and let us know.

Yes, they even make wall shields like you describe. But why poke holes in the nice new double wall pipe?

 

[jason1238]

Thanks BG. You're right...I never thought of poking holes...that stuff was waaayyy to expensive to be doing that unless I have to!

Besides, I don't think I have the right tools for goldsmithing

I'll get the thermometer and check it all out.

 

[swestall]

I bought this recently, its good for checking temps on the stove and the car too! And, very reasonable. The delivered very quickly, a day or so...

http://www.nationaltoolwarehouse.co...D-EC37-4E81-94F6-89BDCCA6AB49}/qx/product.htm

 

[jason1238]

I checked the wall temp last night, and it was reading between 160 and 180. Outside of double-wall black pipe was 380. Stove top was 770+ (the IR thermometer said "---" when I pointed it right at the collar :gulp Short of a runaway, I figure this would be nearly the worst case scenario, as I loaded the stove nearly full and let it rip. I know that shouldn't be done, but I had to once to make sure of what I would be dealing with if it happened accidentally. Pretty sure it hasn't gotten to that point before, because I had that "new stove smell" again. Curiosity satisfied, I cut the air all the way down, and watched the top temp level out at 510-520, the pipe to 190, and the wall to 130.

So, is the wall too hot at 180? The OP was written when the wall "felt" a bit cooler than it did last night. I'm sure the stove was in the 600 to 650 range then.

(BTW, the ambient temp in the room was 92 degrees!)

 

[begreen]

If the stove collar was out of range, did you turn off the lights to see if it was glowing? I'm guessing that you may have taken the stove pipe above 900 degrees.

Something is odd. With a stove top temp of 500, my Simpson DVL stovepipe is running at about 350-400 (Condar probe thermometer). I can briefly touch the outside of my pipe. It's hot, but not burning hot. Wall is 10" away from the pipe and just warm to the touch.

In this case it seems like there are excessive flue temps. Have you examined the stove to assert that the baffle and ceramic blanket are properly in place? I'm wondering if possibly hot flue gases are going behind the back of the baffle and directly up the flue?

 

[jason1238]

No, it wasn't glowing...but I'm sure it was close. The IR will read up to 779 degrees, so by deduction I was somewhere between 780 and 1100?

Either way, it was way too hot! Like I said, this isn't SOP for me. Rather, seeing how hot it would get if I, for example, fell asleep upstairs with the air wide open.

Now that you mention it, I haven't checked that ceramic blanket since last summer when the bird visited That little guy cost me a window gasket. He tried to eat his way through it. The baffles and blanket looked OK, but I didn't pull them out to check the top side (which is where he gave up the ghost). Maybe theres a chunk out of it...

Thanks for the tip, BG...it's going to be in the 50's here today, and I can check as soon as the stove cools off.

 

[begreen]

If it was over 900 it was likely glowing, albeit dully. Make sure there's still a full blanket up there, laying flat and the baffle boards + blanket are seated tightly against the back.