Harman SF250

 
Rraves83
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Post by Rraves83 » Tue. Jan. 03, 2017 10:41 pm

So I've had the Harman for about 1 week now. It's been heating the house well. I've been burning wood thus far. My stove temp is usually around 500-600 and my flue temp is around 200. I've been paranoid about not over firing. When I purchased the stove the seller did disclose a slight crack that was re-welded. Since it has been heavy the last couple days here in the Perry county PA area I decided to let fire burn out and clean the stove real good. After knocking out all the soot and ash I noticed the the area on the top of the fire box that was re-welded has a small hairline fracture or crack. When shining a bright light inside the stove and looking back in stove from flue pipe(obviously the pipe is removed) I can see the light shining up through. It looks like to fix this problem I need to cut out the top baffle area and re-weld a new flat piece of 1/4 steel, not just fix or re-weld over top the crack. My question is can I still burn or run the stove. The hairline fracture only exits to the top area of the stove. So the area is still completely enclosed.

Thoughts guys? I guess in retrospect I should have looked closer at this top area before purchasing stove.

Thanks-

 
titleist1
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Post by titleist1 » Tue. Jan. 03, 2017 10:54 pm

are you saying the crack is in the baffle plate itself?

 
Rraves83
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Post by Rraves83 » Tue. Jan. 03, 2017 11:07 pm

Yes

 
Rraves83
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Post by Rraves83 » Tue. Jan. 03, 2017 11:08 pm

If the area above the rear of the firebox is called the baffle plate, then yes


 
titleist1
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Post by titleist1 » Wed. Jan. 04, 2017 8:57 am

I educated myself a little and looking at the SF250 it seems what you are describing is different than the separate baffle plate like the Mark III has which is what I was picturing.

I would guess the crack in the top plate is from a combination of the previous owner not cleaning flyash laying on top of it in the offseason and overfiring. If it aged like the baffle plates I have seen it corroded/wore away and got thinner and won't take the heat as well.

I would check the top plate closely to see if it has warped or deformed in any way putting stress on where the spiral chamber walls are welded. If there are any cracks there then exhaust could get out of the spiral chamber. I had a real old Mark III with a warped baffle plate that actually cracked the side walls of the stove just below where it was welded to the walls. It had burned a lot of firewood at real high temps so it was a bit abused in its life.

Welding the plate on will seal the crack but I am not sure if it would help whats left of the top plate handle the heat and keep from warping. That said, I'd probably do it and keep a very close watch on it and an extra CO monitor nearby.

 
Rraves83
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Post by Rraves83 » Wed. Jan. 04, 2017 9:32 am

Yeah that's what I was thinking. I may try some rutlands stove cement to see if that temporarily fixes the problem. I don't think I will have time to cut out and re-weld plate during this heating season.

With that being said, if my thinking correct if I switch to coal would that help reduce that high heat from wood flames reaching the top baffle area? I feel since I've been burning wood obviously it's hard to maintain constant heat and also you can load the fire box up completely. Vs with coal not only can you only load to firebricks but the flame isn't also jumping as high. Does this logic makes sense?

 
titleist1
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Post by titleist1 » Wed. Jan. 04, 2017 10:14 am

I agree you'd have better control of the heat with coal than wood. Not sure the furnace cement will do much for the warp-age factor but it can't hurt to try. The exhaust flows through that area anyway and I wouldn't think the thin crack would be changing the draft path very much.

Just don't forget and leave the ash pan door open and have the coal bed go 'neucular' cause that will really stress it out!! :shock:

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