First crack in the Mansfield

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NH_Wood

Minister of Fire
Dec 24, 2009
2,602
southern NH
Hi everyone,

Just noticed my first crack in one of the stones of my Manny. On the lower center left side stone. Long hairline crack the runs both down the stone and across the stone, with a very small notch out of the stone where the two lines meet. Weeping some creosote. I know this is common and won't effect the stoves performance (per the Hearthstone statements), but wasn't fun to see any way. This is year three of full time burning with the stove. Cheers!
 
Hi everyone,

Just noticed my first crack in one of the stones of my Manny. On the lower center left side stone. Long hairline crack the runs both down the stone and across the stone, with a very small notch out of the stone where the two lines meet. Weeping some creosote. I know this is common and won't effect the stoves performance (per the Hearthstone statements), but wasn't fun to see any way. This is year three of full time burning with the stove. Cheers!
Interesting. Seven years burning my Fireview and never had a piece of soapstone crack. Developed a hairline fracture i n the original, large thick top of my Progress Hybrid (they have since changed the design), and Woodstock advised me not to burn if I saw any discoloration at the crack, as it would indicated an air leak and smoke emission. If you have creosote there don't see how you can not be leaking smoke into your living space. CO detector have any reading? I covered my top stone with soapstone slabs I had to seal the air leak until Woodstock got me a new top. If I were you, I'd be replacing that stone.
 
How can smoke be coming out of the firebox with a good draft? Seems that I'd be pulling air INTO the stove, not allowing air to leave the stove. Cheers!
 
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Well now, creosote leaking out does not indicate that smoke and air is coming out. Creosote is a liquid and gravity requires that it not be sucked up into the flue. In addition, suface tension can wick liquids into tight spaces like cracks but has no effect on smoke.

Woodstock has double wall construction on all of their stoves. Might even say triple wall with the PH. It is hard to compare that to a stone stove that uses a single thick layer of stone. I would expect the Hearthstone design is more prone to cracks since it has a single layer with high heat on one side and relative cold on the other. THe double pane window effect of the WS design ought to see less thermal stress plus being a cat stove has such a cold firebox.
 
Well now, creosote leaking out does not indicate that smoke and air is coming out. Creosote is a liquid and gravity requires that it not be sucked up into the flue. In addition, suface tension can wick liquids into tight spaces like cracks but has no effect on smoke.

Woodstock has double wall construction on all of their stoves. Might even say triple wall with the PH. It is hard to compare that to a stone stove that uses a single thick layer of stone. I would expect the Hearthstone design is more prone to cracks since it has a single layer with high heat on one side and relative cold on the other. THe double pane window effect of the WS design ought to see less thermal stress plus being a cat stove has such a cold firebox.

There we go. Seepage of creosote has nothing to do with air/smoke leaking from the firebox to the room. Actually, it just can't happen under most conditions. Air pressure is much lower inside the firebox than outside, creating a force leading to air entering the stove, not exiting. The crack is hairline - can barely be felt with a fingernail. Hearthstone indicates that this is common. Cheers!
 
Many Hearthstone stoves have this and folks seem to get along just fine. Hope it is the same for you NH.
 
Woodstock has double wall construction on all of their stoves. Might even say triple wall with the PH. It is hard to compare that to a stone stove that uses a single thick layer of stone. I would expect the Hearthstone design is more prone to cracks since it has a single layer with high heat on one side and relative cold on the other. THe double pane window effect of the WS design ought to see less thermal stress plus being a cat stove has such a cold firebox.

Yes, multilayered in most places, but the PH's top was originally a single layer (plus a partial heat shield). My single-piece top cracked but showed no sign of leakage, so I ran several more cords of wood through it before switching to the cooktop design (2 layers). I would not be pleased with a cracked piece that had leakage of gas or liquid.

I wonder if a gasket cement along the crack on the inner surface would prevent anything from coming through and if it would hold up over time.
 
I have to believe a hairline crack would let such a tiny fraction of additional air in compared to what the fire needs anyway that it wouldn't make much difference. Although, I sure wouldn't be pleased if my stove cracked.
 
I was thinking of using stove cement over the crack area (inside the stove) once summer comes - I probably will just for good measure. It's really a small hairline crack - so no biggie. Thanks for the good wishes BS, and I'm not very happy Waulie, but not to upset either! Cheers!
 
I was thinking of using stove cement over the crack area (inside the stove) once summer comes - I probably will just for good measure. It's really a small hairline crack - so no biggie. Thanks for the good wishes BS, and I'm not very happy Waulie, but not to upset either! Cheers!
I just noticed my first hairline crack. On the back , lower ,center stone , hairline crack going across the stone and a little creosote leakage. I sent a picture to my dealer and he forwarded it on to Hearthstone. A replacement stone is all I'm looking for , I don't want the stove taken apart unless hearthstone insists. Being in the center ,I cut 2 firebricks to fit in the space between the 2 secondary air runners , covering the cracked stone and giving it some protection against being hit. I know I did not hit the stone with a split, I' have been super careful putting wood in . Not happy as the stove is only 4 weeks old but after calming down my wife , I'm over it .
 

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As long as the crack is tight I would not worry too much about it.
 
Interesting, that is the first actual stone crack I've seen. What I've seen, and have, is hairlines in the stone that look to be veins in the stone. Some are a bit darker than others, but I have no real cracks like that. When I first got my stove (the first year) Hearthstone took the stove back during the summer and rebuilt it; they paid the dealer to take and put back too. I got the impression that they think veins are normal, not so sure about actual jagged cracks like that.

And, for the record, I'd cement the heck out of it if you don't replace it; after all that is what seals the much larger seams and holes the cast iron plates bolt through.

Another thing is that I've seen a few Mansfields (and other stone stoves, here lately that have creosote in the fire box. That should not be. Because when the stove is burnt hot enough and the secondaries are firing; all you have is white walls at the end of the burn. So, I think they need to be opened up a bit to avoid this problem; of course very dry wood too.

I find that the stove top runs around 450 when the stack probe is between 600-800 .(inside double wall) With this much colder single digit weather I've been leaving the air control open a bit more and leaving the pipe damper no more than 1/2 shut; this produces stove-top temps of 500-550, much better to heat our large space. Anyway, in both cases above, no creosote in the stove. And, I can burn two years without getting as much as a quart of dust when I brush the chimney down.

I don't know if anyone has played with it but I have a small hole in my baffle, so I have to change it out next summer. I am thinking of having a thick piece of stainless made up to dimension instead of using the fragile ceramic baffle again. I was looking at the new Lopi Cape Cod hybrid and that is what they are using for the baffle, that sucker has to last a lifetime, so I figure I'll give it a try. I also noticed the tubes in the Cape Cod are a smaller diameter than the Hearthstone, but the same gauge stainless.
 
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