worried about Mansfield stove temps

[ditchrider]

This is the second time this has happened this week.

Hearthstone Mansfield. One year old. I recently changed its location and "mounted" the OAK (I haven't finished the plumbing part yet.

On a reload for the evening fire, I packed it full of seasoned elm. It was about 250-300 degrees on the reload, so I left the air closed down. An hour and a half later it was cranking at 700 degrees. This is the second time it happened this week.

When I moved the stove, the new location of the chimney went through the roof at a lower point. I have a 6/12 roof, so I needed to add two feet to the chimney height. It sticks out of the roof 4.5 feet. Even so, the chimney needs another foot of height according to the installation instructions. It's about six feet from the ridgeline horizontally, but about six inches above the ridgeline vertically, so I thought I would test it out. Overall I have a 19 foot chimney. I thought installing an OAK may reduce the flow of combustion air. I see that I'm wrong. I know reducing the chimney height will reduce draft, but what other concerns would that create?

My fear is overfiring the stove. It was a little over 700 for a few minutes. I turned on two fans and the stove immediately cooled and was down to 650 in 10 minutes. Now 30 minutes after peak it's cruising at 550-600. Any comments or suggestions would be helpful.

 

[pen]

Sounds like you have really great draft.

If this only happens occasionally, part of the issue may be that you reloaded too soon, on coals that were too hot. As a result, your entire fuel load caught and burned at once. One option for you in you need a reload when you are still in that 300 degree range, would be to open the air up fully, rake your coals to the front of the stove, and let it set with the air wide open for a 1/2 hour or so before you reload to help burn those coals down. Also, simply moving the active coals to the very front of the stove, so that they are not spread all over the bottom to ignite the entire load at once, may help too.

If you have this problem consistently, you may consider a pipe damper or perhaps even blocking a bit of your secondary air inlet (but this takes some experimentation to get it right if indeed that is your problem)

pen

 

[ditchrider]

Thanks, Pen. I'll give those things a shot.
I'm hoping the stove thermometer is reading too high.700 on a Mansfield is pretty darn hot. It would really chap me to ruin a year old stove. The owner's manual says 600 is plenty hot. It says don't overfire the stove. It doesn't say what temp is overfire. I'm concerned. The burn last night really made my yarbles hurt.
I've read a couple other posts here on Hearth from Mansfield owners that state it's a good, safe, "knows how to keep a leash on itself" stove. Mine is not the case. Never has been.

I thought about a PM to a reliable source of info here for fear of revocation of my man-card in the public forum and public knowledge of voiding my warranty. But maybe the replies can help someone else with the same issue. I don't have the original man-card anymore, either. It's been suspended several times.

I'm trying to find the root of the problem - me, stove, draft? The burn time is 6-7 hours max. Once I find the draft problem it think the burn time will lengthen.

Just some thoughts.

 

[firecracker_77]

My guess is all that fuel is taking at once. Larger splits take-off slower than smaller pieces. If loading on a hot coal bed, you could put in some larger pieces to slow things down.

 

[kingquad]

Edit:nevermind, Pen already asked the question. Good Luck

 

[Corey]

Sounds like you have several things going on. A taller chimney and OAK would make it easier for the stove to 'breathe' as you have more draft and less restriction by not pulling air from inside the house. You're also pulling in colder/denser air which means more oxygen per unit of volume.

Some have talked about the 'summer bungalow' effect. Means passing EPA tests require stoves set up to burn cleanly in warm temps and with short flues. But these same stoves overdraft in cooler weather and longer flue lengths.

If you think you're over-drafting, two simple solutions would be to either damper the flue or damper the OAK.

 

[pen]

I thought about a PM to a reliable source of info here for fear of revocation of my man-card in the public forum and public knowledge of voiding my warranty.

No worries of that happening around here. Glad you made the post. Keep us posted as you try stuff out and let us know how you are doing.

That said, if it were me. I'd head to the hardware and get a pipe damper if you have single wall pipe and put it in.

If you have double wall pipe, and / or a teloscopic connection, you may be able to buy a short section that contains the pipe damper for an easy install. Costs more, but keeps you from messing around.

pen

 

[Dakotas Dad]

Ours is on 24' of triple wall chimney, nearly a straight shot up, inside a warm chase... I ended up cutting a couple squares of sheet metal, bending an edge to grasp, and setting them over the secondary air holes, held in place with small, very strong, magnets. I slid them open and closed until I felt I had pretty good control of the stove, and it wouldn't go nuclear on a big dry reload. My instal will not allow room for a standard flue damper.

I actually looked at getting an OAK, just to use it as an intake manifold/carburetor arrangement by adding a sliding damper of some sort...

 

[ridemgis]

How are you measuring the temperature? I tossed out my stovetop thermometer upon discovering that it read high by 150 degrees. I go strictly by the IR now and with a similar chimney height the hottest I've seen is 550.

 

[ditchrider]

How are you measuring the temperature? I tossed out my stovetop thermometer upon discovering that it read high by 150 degrees. I go strictly by the IR now and with a similar chimney height the hottest I've seen is 550.

I have a "Rutland" magnetic thermometer. I normally leave it on the center stone, near the flue exit from the stove. Occasionally I stick it 18 inches above the exit on the single wall pipe to see what the flue temperature is.
I'm old school. I like mechanical guages. It wouldn't pain me to get an IR thermometer, but the nostalgia of a wood stove in a farm house would be minimized. I can live with that. It's a much better choice than cracking up my hot rock, or burning down my house.

Another reason I'm posting is because it seems the peak temp doesn't really last long (minutes, and then a 100 degree drop over the next thirty minutes or so), and I'm not sure if my burn time is what it should be. Am I going through wood to quickly and wasting fuel? Do I have draft issues I can safely resolve? Will modifications of my existing install extend my burn time AND not result in other issues or a failure of my system. I'm all for wood heat. It's a renewable resource. But I want to do so safely and have sound advice for others contemplating wood heat.

 

[ditchrider]

Sounds like you have several things going on. A taller chimney and OAK would make it easier for the stove to 'breathe' as you have more draft and less restriction by not pulling air from inside the house. You're also pulling in colder/denser air which means more oxygen per unit of volume.

Some have talked about the 'summer bungalow' effect. Means passing EPA tests require stoves set up to burn cleanly in warm temps and with short flues. But these same stoves overdraft in cooler weather and longer flue lengths.

If you think you're over-drafting, two simple solutions would be to either damper the flue or damper the OAK.

I think I stated the OAK is mounted on the stove, but no plumbing has been done to complete the install. In other words, I'm still combusting air from inside the house so far.

Damping - I was contemplating the install of a damper. I wasn't sure if installing one in either position you mentioned would encourage a creosote buildup. I was hesitant to consider one on the OAK for fear of "double damping on the intake side. However damping the flue would complicate brushing out the chimney.

But I'm liking your input. Thank you.

 

[BrowningBAR]

• I agree with Pen, the damper is a nice, cheap (about $8) solution to bring temps under control when you feel you are running too hit.
• Based on your stove top temps just before reload, I don't think your coal bed is the issue.
• I agree that your stove top thermometer might be giving you a false reading. The Rutland stove thermometer on the 30 is running about 200 degrees hotter than actual stove top temps.
• Check your door and ash pan gasket to get that out of the way.
• You are in Colorado, so I am assuming you are using soft wood or pine which can run hot. Test out your loads and add less fuel on reload to see how it runs.
• Lastly, describe how you are working the air controls.

 

[BrowningBAR]

Also, what does your fire look like when you are running that hot? Is it a violent mess or is it just a high degree of secondaries?

 

[ditchrider]

• I agree with Pen, the damper is a nice, cheap (about $8) solution to bring temps under control when you feel you are running too hit.
• Based on your stove top temps just before reload, I don't think your coal bed is the issue.
• I agree that your stove top thermometer might be giving you a false reading. The Rutland stove thermometer on the 30 is running about 200 degrees hotter than actual stove top temps.
• Check your door and ash pan gasket to get that out of the way.
• You are in Colorado, so I am assuming you are using soft wood or pine which can run hot. Test out your loads and add less fuel on reload to see how it runs.
• Lastly, describe how you are working the air controls.

-Door gaskets are fine
-Deciduous woods. Cottonwood, Elm, Ash and Silver maple. I'm not a fan of pine.
-Normally, with mild coals - Air open full. Throttle down in thirds or so over about 30 minute time frame.
In the case I described in the beginning - The stove was at 300 or so and the coal bed was ripe when i reloaded. I did not rake the coals to the front. I left the air at the closed position. I had a feeling it may have been a little early, but I had no clue it would go nuclear.

 

[ditchrider]

Also, what does your fire look like when you are running that hot? Is it a violent mess or is it just a high degree of secondaries?

It was a high degree of secondaries as it climbed and peaked, however when the temp got down to 550 or so the flames seemed to come from the wood, not necessarily from the smoke. Makes me question the secondary action.

 

[BrowningBAR]

Did the stove feel like it was 700 degrees?

 

[ditchrider]

Did the stove feel like it was 700 degrees?

The wind was a little crazy and very cold last night. My home is still a little drafty. That has an impact on my opinion. The stove was going nuclear, that also has an impact on my opinion. So I'm gonna ponder a moment to be realistic....

I could stand close to the stove and not be driven back by the heat. The glass WAS pretty intense . Honestly I'm still putting the soapstone into perspective versus steel. It wasn't singe-ing my pants, no. I was able to smell the stove, like in the break-in fire on a new stove. I did not hear any popping or cracking from the heat expansion of the stove. Does this help?

 

[ditchrider]

Another note.. If there is an experienced soapstone user, or an industry rep that has an opinion about how these temps affect the stove - talk to me. If you don't want to post, please PM me. I'm not out to hold anyone accountable but myself. It would be good to have a greater understanding. Thanks.

 

[BrowningBAR]

The wind was a little crazy and very cold last night. My home is still a little drafty. That has an impact on my opinion. The stove was going nuclear, that also has an impact on my opinion. So I'm gonna ponder a moment to be realistic....

I could stand close to the stove and not be driven back by the heat. The glass WAS pretty intense . Honestly I'm still putting the soapstone into perspective versus steel. It wasn't singe-ing my pants, no. I was able to smell the stove, like in the break-in fire on a new stove. I did not hear any popping or cracking from the heat expansion of the stove. Does this help?

Then, let's start with the cheap solutions:
Pipe damper
IR thermometer

Pipe damper gives you a security blanket to keep you calm.
The IR thermometer gives you a better understanding as to what the stove is doing when you think it might be freaking out.

A Mansfield at 700 degrees should have been throwing a massive amount of heat. When the Heritage would be at 600+ degrees the heat would make you sweat. I think the thermometer might be giving you some false readings.

I'm surprised you didn't here any creaking. The Heritage would creak as it heated up.

An IR thermomter will run you about $50:
http://www.amazon.com/Kintrex-IRT04...id=1355089743&sr=8-1&keywords=kintrex+irt0421

 

[BrowningBAR]

Another note.. If there is an experienced soapstone user, or an industry rep that has an opinion about how these temps affect the stove - talk to me. If you don't want to post, please PM me. I'm not out to hold anyone accountable but myself. It would be good to have a greater understanding. Thanks.

Hitting high temps like this every once in a while should not cause your stove any harm, but, doing it often or for long periods of time, will cause internal damage to the cast iron parts and could crack the stone.

 

[ditchrider]

Got it. IR is on the way. I stuck a magnet over the OAK tube. I'll play with it a little. Right now the therm reads 575 and I can keep my hand 4 inches from the stove. At two inches away I really don't feel like keeping it that close. My skin starts to bubble.

 

[ditchrider]

I also wonder if my primary air is not shutting off completely. I seem to get a lot of flame from underneath as well as secondary action. When I checked out the slidegate before I installed the OAK the fit of the primary air gate in the slide seemed tight enough that it cause the gate to bend a little outward, maybe 1/16 inch or so. It was definitely not flush with the frame.

Thank you all for your replies. I was thinking along the lines of a damper on my OAK, but I just haven't been burning long enough with EPA stoves. You start messing with the air flow on an engineered combustion system like what we can purchase these days, you don't know what problems you can create by that modification. My old stove was a steel smokedragon. I'm just playing a new game of ball.

 

[Dakotas Dad]

Your primary air control can not / will not shut down all the way. If you ever pull it out, you will find it is shaped or drilled in such a way that it can't close all the way. ( I am not sure of the actual method on the Manny,, have not needed to take it apart yet, did on the Homestead )

On a side note, we ran the Manny near 700 a couple weeks ago, and that was a pretty hot rock. I didn't do the hand test, just took the temp with the IR... But it seemed noticably hotter than usual..

 

[ddddddden]

"Come and get one in the yarbles, if ya have any yarbles. . ."

• I agree with Pen, the damper is a nice, cheap (about $8) solution to bring temps under control when you feel you are running too hot.

+2


Maybe it's a Colorado thing. . .
https://www.hearth.com/talk/threads/secondaries-and-pipe-damper.64699/

My elevation (~4800') is surely a factor too. I wonder how exactly that affects the behavior of the stove. There is less O2 and of course air pressure is lower too. I haven't given much thought to velocities when considering draft through the stove. Could be that my "lighter" air moves too quickly through my stove and that's why the damper helps rather than hinders secondary combustion.

There's just no end to the fascination

I'm not sure if he's talking about his Mansfield or his Englander in this post, but Johnstra had issues with his Mansfield in Colorado too. I think his issue was that he wanted more heat, but still kinda odd that two burners in Northern CO have issues with the Mansfield. . .I'm trying to formulate a conspiracy theory involving the free-breathing Hearthstones at high elevations, but I don't really know enough about the topic. . .maybe send Precaud a msg. I think he is at some elevation in New Mexico, and he has experimented quite a bit with air flow management.

 

[ditchrider]

Thanks, dddddden. Yesterday I placed a magnet over the OAK inlet. MUCH better secondary action and got a much more acceptable burn time. I'm containing more heat. I still have good primary flexibility at startup.

I'm at 4900 feet. Our humidity is terribly low compared what you have out east. 50 percent is a wet one for us, typically 20-30. Over 70 per cent and it's a pretty good chance of precip. We don't get a lot of precip. 15" annual average. I'm thinkin' dry air has better combustion.

It's a nice stove. Everyone tells me what a beast it is. But I wanna unleash the beast and have some advice before I step up to post something in the review section, so I give it a fair chance to shoppers.

Like wise, I started with the Heritage. It was another nuclear stove. No OAK. I upgraded when the dealer gave me the chance because I wasn't sure it had the yarbles to be the exclusive source of heat. Maybe it was but I know I had an immediate stretch of burn time when I stepped up to the Mans. Though if the Manchester was in the lineup at the time I would have seriously considered it. Better rear clearance, side loader. But it just doesn't look as cool. Equinox's little brother lives in my living room.