Harman Mark II Surface Temperature

coalkirk wrote:That means 24" from the rear and 33" from the side. I'm not trying to be a trouble maker. This is a dangerous installation as is. You can reduce these clearances by half with a properly designed and installed heat sheild.

I appreciate your input! The clearance on the left is 44", on the right it's open to the room. The rear clearance is 16'. However the picture doesn't show that there is a 1/2" of heat shield material between the brick and the wall.

The stove was installed by a Harman authorized dealer. They were happy with the installation, as was the insurance company (the same one that made us get rid of the monster wood stove that was there originally).

Do you think the heat shield should be enough to protect the wall behind it???

Edited to add: I forgot to mention, the stove has a blower installed. From what I understand, the blower circulates air inside the rear wall of the stove, thus reducing the rear surface temp. The wall behind the stove has never felt hot, although I have never actually measured it...I'll do that the next time I have it fired up.

I'am a Newbee (although I burned coal in a Warm Morning stove 25yrs ago!) and have been operating my Harman Mark I since late Oct. Since the cold weather ( 14 degrees today and close to 0 tonight) I have been loading with a bottom layer of nut and topping off with stove coal. It keeps my kitchen (where the stove is ) about 80 and the living room (two rooms away) at 70. The burns are lasting at least 12-16 hrs and the temp on the stove ( have mag. on left side level with glass top) is about 400-450 constant and the stack temp is a constant 150-200. I have no baro. and turn the ash air control to 1/2 - 3/4 open.

This stove is great!! I just bought a second (backup) fan so I can have a spare if the one on now conks out. I can also take the one on now off periodical and oil and clean it.

cato, you are running the same stove and stack temps I run at about 20*F. outside. My baro is set to .05 Water Columb. .05 is .01 or .02 higher than many of the guys on this site reccomend. With my stove and pea coal I found the fire lowgy at .03. You probably have about the right draft most of the time then. But, doesn't your stack temp go up to 300* or so when a wind or cold night increases your draft? That is when my baro. realy earns its keep.

Grizzley2:

Nope! My stack temp never gets much above 150 degrees regardless of the wind or cold nites! The only time it may approach 200 or a little higher is when I'am shaking it down and scooping out the ashes before I load a little nut coal on the 'awakened old coals'. The bed or coals gets real hot and flames a few inches high and stack temp around 200 or so - then when I add fresh coal it 'calms' down and by the time I top it off (with nut or stove coal - depending on outside temp) it settles down to a stove temp from 400 or so and stack temp of 150 or so and stays there unless I open the draft on the ash door more or less.

n3hcp -

I would echo Greg's advice about installing a baro damper. I think it will give you more heat with less coal. Where your cabin is empty for long periods, I would maybe put a screen over it when you leave, to block any creatures that might come down the chimney. I capped mine with aluminum foil last summer, but trapping moisture that way caused a lot of rust on the damper.

As to stove surface temp, I measure my Mark I about the same place as yours; my thermometer is just around the corner on the side rather than front. I routinely run temperatures of 650 on cold nights, and push it to 750 on REALLY cold nights. To check against Harman's recommendation, I several times have put a thermometer on the pipe right where it comes out of the stove, and I have never seen it go above 400.

Rberg, when your stove side temp is 650, are you doing nut or stove ?

And while everyones install and draft is different though it sounds like you have a barometer, how many turns open are you running to get 650-700 stove temp? I will say that is really humming though the Harman book says 500 max at the pipe exit and I'm of some opinion that is a surface temp, not a internal pipe temp. 400 at the outlset sounds reasonable.

Thanks for your answers, I'm doing Jeddo pea and it runs really nice and appreciate info on nut and temps you can get when Feb comes.

Side temps of 650 are with inlet opening of about 7/8 to 1 1/4. That will most likely NOT be the same with your stove and chimney. Base your settings on YOUR thermometer, not mine. Eight or nine hours is about the maximum burn time at those temps. A more usual temperature is 550 which easily gives me 12 hour burns. Again, you have the larger Mark II while I have the Mark I, so times may be different for you also.

I burn only nut coal. As you say, every stove and chimney combination is different, and pea has not done well in mine. I tried a little stove coal, and it didn't seem to do well either. If pea works well for you, that's great, and you could experiment with a few bags of nut and/or stove to see if it gives you more heat. Most people say the larger chunks of coal will burn faster and give more heat.

Yes, I do have a barometric damper. My first few months with coal, I did not use one and was skeptical of the value, but now I swear by it. Makes for a much more even burn under varying outdoor conditions, since it automatically compensates for draft fluctuations caused by temperature and wind.

Another important element is the convection blower, that fan on the back that forces air over the back and top and blows it out the front-top of the stove. Last year I didn't use it much because I didn't like the noise, but experimentation has shown that it increases the heat output significantly. Now I use it practically all the time except when the stove is idling at low settings. So if you need maximum heat for your cabin, you will want the fan going full blast. I put a rheostat on mine so at lower stove settings I can also set the fan lower (and quieter).

Edit: Oops! Sorry, Squirrel, you're not the guy with the cabin, that was the first person in this thread.