Hearthstone Shelburne 8372 Operation

[velocity1]

I pulled it all off, added the additional height and then put it back on. It was not as easy as that though. Total weight is probably only 60lbs but cantilever stuff out 9.5 ft and you can imagine how you have to wrestle with it. Disclaimer, if I didn't go to the gym religiously it would have been a lot harder.

These don't twist together. It's 3 screws per connection. The slip fit is pretty tight though. They came apart relatively easily after a year.

Ah yeah i can imagine it’s a little sketchy when dealing with the full length of it all. I’ll probably convert mine over to a similar setup as yours next spring, anchor plate for the class a. I want to add another couple feet for good measure and need to add a brace as well. Just a tricky spot on the roof for a ladder

 

[neverstop]

Ah yeah i can imagine it’s a little sketchy when dealing with the full length of it all. I’ll probably convert mine over to a similar setup as yours next spring, anchor plate for the class a. I want to add another couple feet for good measure and need to add a brace as well. Just a tricky spot on the roof for a ladder

I had put together a roof ridge stand, so basically a platform that hugs the ridge of the roof. Even though it was pretty stable it was too sketchy for my liking, so I didn't use it in the install. Honestly, if I have to do anything with this chimney system again I'll just rent a scissor lift for the day. I have the sooteater chimney cleaner with the white rods so I'm fairly confident I'll just clean bottom up from now on.

When I cleaned out the system most creosote I found was in the adjustable elbow right off the back of my stove. I'm getting rid of that and elevating the stove to meet the rear exit pipe so I suspect the entire system will get a draft improvement from that as well. I was told that having the adjustable right off the back shouldn't impact draft much, but based on my recent cleaning it definitely contributed to my less than ideal draft.

 

[begreen]

I had put together a roof ridge stand, so basically a platform that hugs the ridge of the roof. Even though it was pretty stable it was too sketchy for my liking, so I didn't use it in the install. Honestly, if I have to do anything with this chimney system again I'll just rent a scissor lift for the day. I have the sooteater chimney cleaner with the white rods so I'm fairly confident I'll just clean bottom up from now on.

When I cleaned out the system most creosote I found was in the adjustable elbow right off the back of my stove. I'm getting rid of that and elevating the stove to meet the rear exit pipe so I suspect the entire system will get a draft improvement from that as well. I was told that having the adjustable right off the back shouldn't impact draft much, but based on my recent cleaning it definitely contributed to my less than ideal draft.

It's fairly common to see accumulation in the horizontal run off the rear exit and where it hits the wall of the cold outside tee. Flue gases move slower there.

 

[neverstop]

It's fairly common to see accumulation in the horizontal run off the rear exit and where it hits the wall of the cold outside tee. Flue gases move slower there.

ok good to know, everything else just had powder on the walls of the flue

 

[neverstop]

Welp, after installing thermocouples on the flue / stove top I've realized that I've been using the incorrect emissivity settings on my IR gun for the past couple of years. I've also confirmed the bi-metallic temperature gauges aren't very precise. I have been using 0.7-0.8 for emissivity for the black stove/flue, but I should have been using 1.0 because it's more or less a black body (OMEGA reference).

Using the lower settings the IR gun was reading ~407 F while the thermocouple was reading 260 F. With the correct setting the IR gun is reading ~330 F while the thermocouple is reading ~305 F (can't measure at the exact same location because the thermocouple is being held down by the bi-metallic gauge). For the flue measurement, the IR gun is +/- 5 F from the thermocouple.

Aside from the other problems I've had I feel like this also explains why I've found it so hard to control the temperature of the stove for the past couple of years. I've been reading artificially high flue/stove temperature values with my IR gun. Hopefully this makes controlling the stove easier going forward.

 

[N_Weeks]

Good morning, fellow Shelburne burners (tried hard not to write a pun there),

Bringing this thread back to life to ask some questions on your collective experience since this thread started re: controlling STT and the top end of the acceptable range for this stove, hot reload methods, etc. I've poured over this thread on many evenings recently while laying on my as my stove "rages" behind me. I attribute most of my nervousness to being a new stove owner/operator and a slight perfectionist, but since y'all have been burning for a bit I wanted to get your opinions

I'm new to this stove - and stoves in general - and have been learning how this thing works for the past couple months since installation. Quick notes on setup:

- Double wall stove pipe w/ (1) 45* bend
- 21' interior chimney, straight up
- Wood is what I would call "fine" - I just moved in and am picking through a load of seasoned wood delivered in summer. It's mostly 18%-20% MC...so acceptable, but not ideal. I have an extra 3 cords I split last summer sitting in wait for next year, so I'll be ahead of it after this.
- Live in Bartlett, NH, so it's cold, humid, and windy most of the time between 12/1 and 3/31.

Loving the stove so far; my only concern is that I'm unable to burn it at an acceptable temperature on fuller loads. I haven't installed flue probe yet, but it's in the works, so I'm working with magnetic stovetop thermometer placed directly against the stove pipe collar, right in the center. I also put another in a corner of the stove to see the difference between what I deem the hottest part of the stovetop vs. elsewhere, and it usually reads -150 F. The manual lists 600F as the max STT, which in my experience is nearly impossible on hot reloads. I've had better luck on cold reloads keeping it below 600 if I want, but since it got consistently cold out (highs below 30) I've noticed that burning at 500, 550, etc. doesn't cut it. I've maxed out at 675F - 690F a couple times and a typical bed time load hits 650 and hovers there for a bit before slowly falling.

I don't need or want to burn at 700 all the time, but my house is a 1981 saltbox with 2x4 walls, so 600 - 650 seems to keep the place more comfortable on colder days and long nights. It's currently 20F and calm; I woke up to 63F house with a good bed of coals. Pulled coals to the front, created opening at doghouse, and reloaded to +/- 75% capacity with a couple 4-5" splits infilled with small/mediums above. Tried to keep splits from interlocking, as I've noticed this slows down startups/is annoying. Front log on coals was placed on sleepers. Proceeded to cut air down as quickly as I could and reached acceptable burn in 20-25 mins (pics below). STT reached 650 within another 15 mins and peaked at 670 or so before dropping down to +/- 650, where it's been for the past hour and a half. House is slowly warming up (66 and climbing now, 2.5 hours later), and the fire looks good with mellow primary and secondary burn.

Are these temps/burns normal for this stove on hot reloads? It seems the 600 max STT in the manual is a total farce, but I would hate to find out I've been burning too hot for this stove and cause unnecessary damage. If the 600 max is indeed a max, can I set these burns up differently to keep max temp lower?

Should I even be worried about any of this? Am I wasting my time writing this post? Just trying to make sure I'm burning responsibly and efficiently.

Thanks in advance.

 

[neverstop]

I have it setup with a rear exit, but the area circled in purple below (as well as it's mirror on the other side of the mid-line) seems to be the hottest area of the stove top in my experience. There is a significant drop-off in temperature moving away from this area. Moving an inch to the right can translate to ~75 F difference lower in temperature.

If I stuff the stove full it's basically impossible to keep it below 650F. The 600F in the manual is a ridiculous #, I assume they put that in there just so they could deny warranty claims. General recommendation for cast stoves seems to be 725-750F max; Woodstock (soap stone stoves) say 700F max. So, aiming to keep it below 700F and the occasional peak to ~725F is most likely the real answer. I doubt you see any real damage until you're actively running the stove above 700F consistently, and not just peaking there.

The magnetic thermometers are not very precise or accurate. IR guns are better, assuming you have the settings correct for your stove material. I've been using a k-type thermocouple, I trust that over the other 2 measurement devices.

Various things will effect the peak temperature of a burn. One thing I actively try to do is I try to avoid putting too many splits with bark in, I've seen large spikes in temperature when I've done that, and not necessarily at the beginning of the burn either.

I don't use sleepers on hot reloads, and I only leave a path behind the primary air inlet for the first column of splits. When I've left a path for the entire load I've noticed more of a chance to have all of the wood off gas at once.

 

[begreen]

It would be very helpful if the manual showed where to read the recommended temperature. The area before the flue exit is where the cat sits. It's no surprise that area is going to read hotter with a 1200º cat sitting under it.

 

[neverstop]

It would be very helpful if the manual showed where to read the recommended temperature. The area before the flue exit is where the cat sits. It's no surprise that area is going to read hotter with a 1200º cat sitting under it.

the cat actually sits directly below the flue. the area above circled in purple is where the bypass door is located. I'm 90% sure the by-pass door is located on a higher plane the cats (which sit vertically below the flue in the back of the stove), and gases just "pool" in front of the by-pass door because it's a high point. Anyway, that's my theory

 

[begreen]

the cat actually sits directly below the flue. the area above circled in purple is where the bypass door is located. I'm 90% sure the by-pass door is located on a higher plane the cats (which sit vertically below the flue in the back of the stove), and gases just "pool" in front of the by-pass door because it's a high point. Anyway, that's my theory

Sounds plausible.

 

[N_Weeks]

I have it setup with a rear exit, but the area circled in purple below (as well as it's mirror on the other side of the mid-line) seems to be the hottest area of the stove top in my experience. There is a significant drop-off in temperature moving away from this area. Moving an inch to the right can translate to ~75 F difference lower in temperature.

If I stuff the stove full it's basically impossible to keep it below 650F. The 600F in the manual is a ridiculous #, I assume they put that in there just so they could deny warranty claims. General recommendation for cast stoves seems to be 725-750F max; Woodstock (soap stone stoves) say 700F max. So, aiming to keep it below 700F and the occasional peak to ~725F is most likely the real answer. I doubt you see any real damage until you're actively running the stove above 700F consistently, and not just peaking there.

The magnetic thermometers are not very precise or accurate. IR guns are better, assuming you have the settings correct for your stove material. I've been using a k-type thermocouple, I trust that over the other 2 measurement devices.

Various things will effect the peak temperature of a burn. One thing I actively try to do is I try to avoid putting too many splits with bark in, I've seen large spikes in temperature when I've done that, and not necessarily at the beginning of the burn either.

I don't use sleepers on hot reloads, and I only leave a path behind the primary air inlet for the first column of splits. When I've left a path for the entire load I've noticed more of a chance to have all of the wood off gas at once.

View attachment 332840

This all tracks with my experience. I've read this entire thread multiple times and watched the realization dawn on everyone that 600F isn't possible with this stove, but I wanted to see if there had been any means/methods epiphanies over the past couple years. I've seen a lot of the things you guys discussed, namely mellow stove temp then sudden raging secondary burn leading to big increase in heat and crazy secondary burn in the air wash against the glass which leads to 700+ STT. Trying my best to take note of what I'm doing when I burn so I can try to figure out what leads to certain burn characteristics. Fun little activity, this is.

One thing I have noticed when the secondary burn is really screaming from the rear tube and primary has died down is that I can see a "haze" of sort floating over the log pile; does anybody know what that is? Are those the gasses from the wood? Does that mean I have an issue with draft leading to a firebox that appears calm at 1200F? I haven't had any back puffs or anything so I think my draft is fine, but the first time I saw the floating haze I was mesmerized. Do you let it roll when primaries die and the secondary burn kicks up, or do you try to bring back some of the primary by introducing more air to burn off some of the excess gasses? Like I said, I'm new to this and didn't grow up with a stove, so I'm learning purely by experience.

As far as @begreen 's note about the manual, I agree. I read the thing front to back before burning a thing and it turns out that it's not very helpful. Great stove, not so great literature.

 

[neverstop]

This all tracks with my experience. I've read this entire thread multiple times and watched the realization dawn on everyone that 600F isn't possible with this stove, but I wanted to see if there had been any means/methods epiphanies over the past couple years. I've seen a lot of the things you guys discussed, namely mellow stove temp then sudden raging secondary burn leading to big increase in heat and crazy secondary burn in the air wash against the glass which leads to 700+ STT. Trying my best to take note of what I'm doing when I burn so I can try to figure out what leads to certain burn characteristics. Fun little activity, this is.

One thing I have noticed when the secondary burn is really screaming from the rear tube and primary has died down is that I can see a "haze" of sort floating over the log pile; does anybody know what that is? Are those the gasses from the wood? Does that mean I have an issue with draft leading to a firebox that appears calm at 1200F? I haven't had any back puffs or anything so I think my draft is fine, but the first time I saw the floating haze I was mesmerized. Do you let it roll when primaries die and the secondary burn kicks up, or do you try to bring back some of the primary by introducing more air to burn off some of the excess gasses? Like I said, I'm new to this and didn't grow up with a stove, so I'm learning purely by experience.

As far as @begreen 's note about the manual, I agree. I read the thing front to back before burning a thing and it turns out that it's not very helpful. Great stove, not so great literature.

I'm not 100% sure what you mean by "haze", but my assumption is you're referring to the smoke coming off the wood. If you close off the primary enough you'll effectively stop primary flames on the wood as you said. The result is that the wood "smolders" and releases smoke. This smoke is the fuel for the secondary flames. At this point you've already established the rate at which the volatile gases are being released from the load based on how much you've "charred" the wood so far during the burn. If you were to add more primary air you could possibly lower the stove temperature by sending more air up the chimney, but you'd also be increasing the rate of gas release from the wood by further "charring" it.

Once the primary is fully closed you're at the mercy of the chimney draft because the secondary air inlet is un-regulated. If flue gases increase, draft increases, and you have more air pulled in. So, if you have a large off gassing event that causes a temperature spike and your flue temperature increases you can have a positive feedback loop. This is how you get a run-away stove situation. The more consistent I can be with my loads/timing the more predictable the burn; one of the reasons I don't like burning wood with bark. If it's falling off (which most of it is if the wood is sufficiently dry), then I pull it off. If it doesn't come off easy I just throw it in.

If you feel like the stove is running away from you there are really only have a couple of options.

• Open the by-pass and fully open the primary
  • This will feed more air into the stove and thus more air up the chimney. Although, my experience with this is that the flue/STT just continue to climb if you're early on in the burn.
• in addition to the above, open the stove door
  • this basically turns the stove into an open fireplace introducing A LOT of cool room air into the stove and up the flue. It's counter-intuitive, but it works. Flue/STT will spike for a bit as the fire rages with the extra air but once enough cool air is introduced (and hot air dumped up the flue) into the system things will start to cool down.
• If you think you have a chimney fire the best option is to open the by-pass, close the primary and toss in a Chimfex stick which should starve the system of oxygen.

I found it interesting you used the phrase "appears calm". The secondaries can get pretty aggressive; although the shallow firebox adds to this visual effect. When I get the "gas grill" effect from the secondary air tubes I usually say to myself, "crap, here we go" because I know I'm in for STT that flirt with 700F.

It's all a learning process, and it's hard to read words online and transfer that to stove control without some hiccups. I've had some spikes close to 800F when I didn't pull the coals to the front and the entire load off-gassed at the same time. I've had other off-gas events where the majority of the door glass has become sooted because the wood was close enough to the door and the entire load off-gassed at once. However, at this point I have a pretty good grasp on controlling the stove (knock-on-wood).

 

[N_Weeks]

I'm not 100% sure what you mean by "haze", but my assumption is you're referring to the smoke coming off the wood. If you close off the primary enough you'll effectively stop primary flames on the wood as you said. The result is that the wood "smolders" and releases smoke. This smoke is the fuel for the secondary flames. At this point you've already established the rate at which the volatile gases are being released from the load based on how much you've "charred" the wood so far during the burn. If you were to add more primary air you could possibly lower the stove temperature by sending more air up the chimney, but you'd also be increasing the rate of gas release from the wood by further "charring" it.

Once the primary is fully closed you're at the mercy of the chimney draft because the secondary air inlet is un-regulated. If flue gases increase, draft increases, and you have more air pulled in. So, if you have a large off gassing event that causes a temperature spike and your flue temperature increases you can have a positive feedback loop. This is how you get a run-away stove situation. The more consistent I can be with my loads/timing the more predictable the burn; one of the reasons I don't like burning wood with bark. If it's falling off (which most of it is if the wood is sufficiently dry), then I pull it off. If it doesn't come off easy I just throw it in.

If you feel like the stove is running away from you there are really only have a couple of options.

• Open the by-pass and fully open the primary
  • This will feed more air into the stove and thus more air up the chimney. Although, my experience with this is that the flue/STT just continue to climb if you're early on in the burn.
• in addition to the above, open the stove door
  • this basically turns the stove into an open fireplace introducing A LOT of cool room air into the stove and up the flue. It's counter-intuitive, but it works. Flue/STT will spike for a bit as the fire rages with the extra air but once enough cool air is introduced (and hot air dumped up the flue) into the system things will start to cool down.
• If you think you have a chimney fire the best option is to open the by-pass, close the primary and toss in a Chimfex stick which should starve the system of oxygen.

I found it interesting you used the phrase "appears calm". The secondaries can get pretty aggressive; although the shallow firebox adds to this visual effect. When I get the "gas grill" effect from the secondary air tubes I usually say to myself, "crap, here we go" because I know I'm in for STT that flirt with 700F.

It's all a learning process, and it's hard to read words online and transfer that to stove control without some hiccups. I've had some spikes close to 800F when I didn't pull the coals to the front and the entire load off-gassed at the same time. I've had other off-gas events where the majority of the door glass has become sooted because the wood was close enough to the door and the entire load off-gassed at once. However, at this point I have a pretty good grasp on controlling the stove (knock-on-wood).

This is super helpful, thank you. Yes, the haze is the smoke that just floats there and I suspected that's what feeds the secondary burn.

I've been trying to find the sweet spot with getting a good burn around 600-650 w/o going too far over that, and I've noticed that the fires that get hotter than I'm shooting for are the ones where the gas grill burner kicks in in the background. As you said, once it's done, it's done, so I've been playing with when to reengage the cat and how the fire should look when I start to close the primary air. Still a work in progress, but I'm marginally better at it now than I was a month ago. It seems like the best outcomes, in terms of manageable temps, occur for everyone when the primary air is closed as aggressively as possible, no? Right now I'm just trying to gauge what that looks like--it's somewhere between flames lapping out from under the front split and a box full of flame, and I'm pushing it as close to the lapping stage as I can to try to control off-gassing. Do you have a tell tale visual cue that says "it's time to start closing the primary" or "reengage the cats now"? I know there are a ton of variables, so a visual cue is helpful for me since fire looks like fire, regardless of your chimney height/flue setup/starting STT, etc.

I've also been wondering what I can do in the event the stove gets too hot and looking around the internet, and you solidified my understanding of that. I assume when you say open the door, you mean open it a little bit, not all the way, correct? I hope I don't have to do it, but more knowledge is always good.

 

[neverstop]

This is super helpful, thank you. Yes, the haze is the smoke that just floats there and I suspected that's what feeds the secondary burn.

I've been trying to find the sweet spot with getting a good burn around 600-650 w/o going too far over that, and I've noticed that the fires that get hotter than I'm shooting for are the ones where the gas grill burner kicks in in the background. As you said, once it's done, it's done, so I've been playing with when to reengage the cat and how the fire should look when I start to close the primary air. Still a work in progress, but I'm marginally better at it now than I was a month ago. It seems like the best outcomes, in terms of manageable temps, occur for everyone when the primary air is closed as aggressively as possible, no? Right now I'm just trying to gauge what that looks like--it's somewhere between flames lapping out from under the front split and a box full of flame, and I'm pushing it as close to the lapping stage as I can to try to control off-gassing. Do you have a tell tale visual cue that says "it's time to start closing the primary" or "reengage the cats now"? I know there are a ton of variables, so a visual cue is helpful for me since fire looks like fire, regardless of your chimney height/flue setup/starting STT, etc.

I've also been wondering what I can do in the event the stove gets too hot and looking around the internet, and you solidified my understanding of that. I assume when you say open the door, you mean open it a little bit, not all the way, correct? I hope I don't have to do it, but more knowledge is always good.

You're going to want to open the door fully. I've seen some suggestions of opening it for a minute or so, then closing it for 50% of that time, and repeating that cycle.

For your other question about when I start to close it down I'll break it down into 3 categories. I'll also lay out how I view the primary lever.

Primary Air Lever:
The control isn't linear because the primary air opening on the bottom of the stove is a circle and the plate that you slide to cover the opening has a straight edge.

• 100% open
• 50% open - brown knob under the ash lip and knob tangent to the ash lip edge
• 25% open - there is the slot on the primary air control plate and a screw (or spacer of some kind) that has a washer on it that you slide the plate on. I usually just stick the tip of my pointer finger in that slot and push the control lever in until the tip of my finger is pressed up against the washer edge. It probably equates to ~0.25" of space between the washer edge and the end of the slot
• 12.5% open - the washer edge covers the entire slot. you need to stick your head under to see it and all other levels
• 6.75% open - half way from the 12.5% position to fully closed. it's a good idea to scratch/marr the lever in it's closed position so you know what is fully closed. I'd mark it against the edge of that washer I described above so you have a visual on how much is left.
• 6.75%-0% open - it's a crap shoot

I've toyed with the idea of creating 2 sheet metal pieces that attaches to the control that gives you a better idea without sticking your head under the stove. Something along the lines of a reference line and a stamped "ruler" that you'd view from the left side of the stove. Something like what I posted about here : https://www.hearth.com/talk/threads/indexing-a-damper-choke.201351/post-2694747 but viewable form the side of the stove so it doesn't stick out into the room like the part would in the link above.

Cold Starts:
I normally never fully load on a cold start. I use it as my "high burn" for the day and to get the chimney fully up to temperature. So I usually leave things fully open until the flue climbs up to 360-380 (external single wall). Then I'll start closing down the primary because most likely the cat isn't in operating range yet. I'll close it down by 50 % increments as described above (50, 25, 12.5 etc). I wait for the flue temperature to stabilize (some upward movement) before further closing it down. I have thermocouples hooked up to the stove top and flue (post about that setup https://www.hearth.com/talk/threads...toring-with-raspberry-pi.200475/#post-2688212) that I use for monitoring the temperatures.

Once the cat is in range I'll close that, and wait for temperature recovery without touching the primary. At some point the flue temp doesn't stabilize and then I'll open the primary half the amount I previously closed it and let it do it's thing.

"Cold Reloads": If the STT is below 200 and there are a handful of coals left I don't consider it a hot reload. I treat this like a cold start, and throw 3 pieces of bark in there with a thin piece of kindling to get things going again. Need to be careful though, if you leave things fully open you can see very high temps quickly with the bark especially if you load too much of it. So that'll burn for 10-15 minutes with the intention to heat the chimney and normally the STT gets back above 300F when I do this.

Hot Reloads: anything with a sizeable bed of coals I consider a hot reload
I normally wait until the flue temp is above 300F to engage the cat, but if it's very cold out or if the fire catches very fast and starts to rage I'll engage it quicker. Same goes for closing down the air. On cold starts I want to throw heat up the chimney to establish a good draft and fully heat the system. On hot reloads my main goal is controlling the amount I char the wood.

For a visual, if I can see the flames being pulled up/around the baffle then that's a sign I should probably close the air down the next increment. You should be able to see a visual impact from the air change in the flame activity within 1.5-2 mins of making the change. You should see the flames become "lazier" and they should retreat from the baffle. If you don't see a change within 2 minutes it's probably a good idea to move onto the next increment of closing down the primary. Then wait for temps/flame activity to stabilize/become less lazy to continue to close it down. Eventually, you'll get to a point where either the air is fully closed or the temps don't stabilize or the flames become lazier. That's when I open it back up half the previous move.