Newbie Overfire Problems.

Hi, I am new here to the forum and new to burning coal. So far I have gotten off to a really rough start. I have a glenwood oak #30 and I also have a much smaller Record foundry Maple stove.. I believe that is the model, no markings. They are both old stoves. I am set them up the way that I would an ordinary wood stove, just normal 6 inch piping with a mpd. I am burning kimmels nut coal.
The problem that I am having is that I can't seem to avoid an overfire. No matter what combination or settings I use, or which stove it is. It starts fine. I will open the ash pan door vents set up the fuel, open the damper wide open and light it up. You can hear it drawing hard through the ash pan vent and in a matter of a couple minutes I am up and running without a hitch. So I will add another thin layer of coal, wait till the flames are dancing above that and then add another.
Up until this point all is well. Then I will drop the damper down to a bit shy of closed, drop the air vents down till there is just a crack open in hopes that limiting the air will give a nice slow burn. It never works out that way.... The entire contents of the stove will burn immediately becoming red hot, glowing and overfiring the stove. It has gone to the point of turning the walls red through the layer of fire stone covering them. I have tried every combination, opening the MPD more, opening the vents in every manner conceivable, it all ends the same way with an overfire. I shut off all the air vents and yet the temp still keeps climbing. The exhaust piping climbs up to about 400 to 500F with the stove being off the charts for my laser therm. at over 610F.
I am having a hard time narrowing down the variable that is responsible. I am not sure if it is because the stoves are old and have so many air leaks. On the record foundry stove even with the vent closed their is a bit of a gap at the ash pan that air can enter the bottom of the stove through, however this is the way the stove is designed and not a defect, so I tend to think it should run as it was designed without issue. I am not sure if I am having overdraft issues. The chimney is a straight masonry chimney without any internal piping that lays on the side of the house. The top is uncapped the house lays nestled down surrounded by woods with trees that tower over the house. I have had a back draft in the past o ridiculously windy days, which led me to buy a cap, but, I am yet to install it. Most of the time I seem to have a good draft though. Not sure if it is too good.
The overfiring happens with both stoves. Not sure if a baro is the answer, I have never used one before. it seems to take a lot of variables away though, that couldn't seem to hurt.
I have seen similar stoves in videos being run with a nice slow burn. The stove registering around 420 ish and the exhaust pipe significantly lower. The videos have claimed to run the stove for hours without refilling, whereas mine has a few hours fully loaded at best before it burns itself out, leaving behind large chunks of partially burnt coal. I am sorry for the long message, I am trying to give as much info up front as possible to help get the full story right away. I would love to be able to experience all the benefits of coal burning without worrying about burning down my house.

Any thoughts on the issue would be greatly appreciated!

Welcome to the board.

It sounds like you have a MASSIVE air leak BELOW the firepot/grates.
Start a decent fire with either kindling or a small amount of coal. Leave the MPD open, shut the primaries and the secondary. Using anything that makes smoke (incents for example), go all the way around the base of the stove and see where smoke is getting sucked in.

Fix that leak.

Repeat the process until you cannot get the smoke to draw into the stove.

Best of luck and keep posting your results.....and pictures.

Welcome.

I Agree. Too much air getting in somewhere below the grates.

The ash drawer door, or the primary air slide damper in it, may have a poor fit from wear and need to be better fitted.
Check for air leaks around the ash drawer base pan in under the base.

Those slide dampers can get worn and/or the spring inside the handle that is meant to hold the slide damper plate close to the ash drawer door gets weak from years of high heat. Try shimming the spring inside the handle with a washer that has a slot cut in it to allow it to be slipped between the handle and the ash drawer door and fit around the damper plate shaft that goes up into the handle.

Another point. I find that the Tractor Supply Kimmel's burns very hot, thus making it that much tougher to control in a leaky stove with a strong draft. If you can get some other brand of anthracite coal give that a try. My Kitchen range, which is about the same vintage as your #30, gets tough to hold back with Kimmel's, but it's very controllable with Blaschak.

After you check for air leaks, if it still wants to burn hot, you may have a strong drafting chimney system. You can try adding a second MPD plate to increase resistance to exhaust flow. I would not recommend using a baro with the #30.

Another old trick to slow a well drafting stove is to sprinkle some ashes over the top of the fire. Not enough to smother it. Experiment by adding small amounts. Just enough to add some restriction to air flow up through the coal bed and slow it down.

Paul

How about some details on this chimney? How tall is it and is it interior or exterior?

I agree, there must be unknown combustion air getting in your stoves. Possible bad seals on the ash pan doors. You can also do a dollar bill test, close a dollar bill in the door seals and see how much effort it takes to pull then out. A smoke test is a great way too.

Hi there. You have come to the right place.
Your Glenwood Oak 30 is one of the best stoves ever for burning coal. You should be easily able to control the fire for whatever heat output you want. The obvious answer is that you have a massive air leak or combination of leaks in the stove.
You have to find them and correct them. The stove may need to be taken apart and resealed. Problems of this sort often occur when stoves are used without being properly restored.
Taking the stove apart is not complicated. It's just dirty and tedious. Basically what it entails is replacing all of the bolts and resealing all of the joints with new cement. Also the fit of the doors are crucial. When the stove was made the doors fit with air tight seal and the spring loaded dampers also were air tight. Most often the doors can be fixed by bending the hinge pins back to their proper alignment.
I know it seems like a giant problem but you can solve it.

Sorry, I misspoke above. It's the loading door an a #30 that has the slide type damper.

The two ash door rotary dampers are also spring loaded to keep them sealing tight. They can have heat-weakened springs too.

Sometimes, they just get rusted and need a few drops of oil. Then work the damper back and forth to get the rust to flow out and free up the spring.

Paul

First off I would like to say thank you to all the people that took the time to respond to my question. I didn't expect the fast response I got and from many different people. I seem to have stumbled upon a great online community. I am going to look at the general consensus that their is additional air entering the stove. I think that I am going to go with the incense smoke test. For the person that asked about my chimney I have not made it out to get a more accurate measurement, but it runs attached to the side of the house and goes about 6 feet above the roof which is two stories high, so a rough estimate accounting for the exposed basement would be around 30 ft high. Anyway I will keep everyone updated on anything that comes to light. I will be getting on it a.s.a.p as it is not too pleasant at night in So. NH right now and I despise buying and using oil.
I was also curious about the comment about not using a baro with the glenwood oak. I am just starting to learn all these things and figure them out. Why would you not use one? Is this just a preference or is there some negative consequence of using the combination?
Anyway, again, thank you to all that took the time to answer my question and help me out.

I would expect the manual damper to seriously limit the burn rate of the stove even if air is reaching the coal bed due to leaks. if installed correctly. Are you sure the manual damper is closed?

Yeah, I'm sure. It fits appropriately. Everything is good on that end, with the damper open, there is almost a roaring of the air being sucked in and sucked out the chimney. I almost completely close it and it settles down to a still vigorous fire significantly less so.

Be careful using the unit as it is , over firing can ruin your beautiful stove, locate and reseal all leaks as you find them use a ciggarette or incense while stove is running to locate where air is getting in , than you can install a baro to help with efficiency , keep a bucket of dry sand near stove to smother any runaway fires , maybe try small wood fires while diagnosing . Cover the entire ash door with aluminum foil which will tell you whether slides on door are the cause! Good luck and keep us posted , Shawn

Seal the ash door with self adhesive 1/8" gasket that will stop the underfire leaks (probably). That will stop the runaway unless you have massive cracks elsewhere. Then let's see what happens. Leaks over the fire will be important if you wish to run on low. My Wings Best is great at medium to high fires but below 200* the stove has to be tightened down more.
Most of these cylinder stoves are bit leaky but by running on over the fire air only you can get real control (open the secondary air wide), at least that is what I am noticing. My Our Glenwood #9 taught me that along with my post graduate instructors teachings (thx dlj - thx William). How low can you go? 175* for 36 hours and I am still working on it. The final act will be the Glenwood #8 untended for a week on super low. Big stoves in small rooms - yeah. It just fits my application. Once I master this, Pierres (nortcan) micro gasket rebuild is in my future. I have only just started to play with my base heater menagerie. Have fun with your Oak.

A

I finally got some time to really take a look at my stove and try out a few suggestions. I figured that I would use the record maple for a test pilot, being much smaller, would be easier to control if things went south fast. so I ripped it down completely to start from ground zero. I started by adding a gasket around the ash pan and cemented everything airtight. As was suspected, there was massive air leaks. I sealed them and everything else I could up tight. While taking a peak up the chimney with a mirror through the wall hookup, I discovered that even without a fire going I had what I would consider a pretty heavy draw... not sure being new to it all and not having any means to measure the draw, but it was drawing in a tissue I held in front of the opening. So I attached a mpd followed by a length of pipe then a baro leading into the chimney . . I am running the stove now with Kimmels nut coal. I am a little over an hour into my burn. My ash pan vents are closed, top air vents are wide open, mpd is almost completely closed and the baro is wide open. my numbers are as follows: lower exterior portion of the stove filled with the coal bed: off the charts at + 610°F, upper surface portion of stove (not filled with coal bed) 460°F, pipe beyond the mpd is about 340°F, pipe beyond the baro leading into the chimney is at about 190°F. The coal bed is completely engulfed despite my efforts to slow the burn. I have heard Kimmels nut coal burns hot, are thread numbers considered acceptable? I am happy with reaching below 200° entering into the chimney, but am far from the black coal with blue flames dancing over them I see in some coal burning videos. Should I try new coal? Try a different config, or leave well enough alone? Any thoughts or recommendations are welcome and appreciated.

Did it simmer down at all later into the burn? That still seems like it's running kinda hot. You seem to be making progress but you still should be able to idle it down more. I suspect there is still air getting in under the coal bed somewhere. Have you smoke tested around it to see where else it could be drawing in air?