Does Anyone Know Anything About This Harman Stove?

I heat with a Mark III in a 1800 sq ft home. New one though. In the basement. I use at least 4 to 5 tons here in Northern NH. A Mk I is alot smaller and wouldn't heat my home very well here. Maybe if I ran it so hot that I"d have to shake and reload every few hours. Right now I just do it 2 times a day when cold. 1 time a day in fall or spring temps.

My stove is located on the first floor of a two story house. The wood stove that we currently use heats the living room and bedrooms upstairs; however, because the stairs are in the middle of the house, they block the heat from reaching the dining area and kitchen. The stair wall on the living room side is open, allowing the heat to rise up the stairwell to the upstairs; the wall on the dining room side is solid, with two door ways, so the heat is blocked. So, even if I move the Mark 1 into the living room, we would still need a smaller secondary source for the rest of the house. There is duct work, from the oil furnace we do not use, that runs from one end of the house to the other (starting right above the wood stove and ending in the dining area) . My father-in-law suggested cutting a hole in each end and putting in a fan to blow the hot air into the colder rooms. I will hook up the Mark 1 and keep it to a low simmer in the kitchen this year, re-evaluating after this winter which stove to have as a primary heat source next year.

I have been told that a local Amish feed store may sell coal, so I will check it out and see about getting a small amount to play with once I get the Mark 1 hooked up.

Thank you for all of your help and words of wisdom so far

I will hook up the Mark 1 and keep it to a low simmer in the kitchen this year, re-evaluating after this winter which stove to have as a primary heat source next year.

Next year the Harman will be the primary heat source.

I live in a drafty old farmhouse also, approx. 2000 sq ft. My Mark I heats the entire house until we get winter temperatures, then more heat is needed. I'm currently installing a coal fired boiler feeding a heat exchanger in the duct work for the oil fired hot air system. I'm going to use the blower in the oil furnace to circulate the hot air.

I tend the Harman twice a day, takes less then 10 minutes each time. A lot less work then firewood, this I know from experience. I heated with wood using 2 stoves for 16 years, I still have a Fisher insert in the fireplace.

As others have said fill the firebox completely with coal. The amount of heat you get is controlled by the amount of underfire air you give the coal as opposed to wood where the amount of firewood you add controls the amount of heat you get.

I would look into tapping into that existing ductwork. I had a heck of a time in my previous house with this stove.

It was 1200sf on a slab. I would have to run the living room at 90* to get the bedrooms to 65*.

Then I put a 14" cube in the attic above the stove and some of that flexible HVAC duct down to the bedrooms. It made ALL the difference.

After that, I had no more than a 10* difference through the whole house.

It's all about the circulation. Take a birthday candle and walk around your house to get an idea of how the air flows. I used to be able to lay the flame down 90* from the wick when I was standing in the end of the hallway down by the bedrooms. That's good airflow!

And hold the candle high and low. The air can flow in one direction near the floor and the other by the ceiling.

Congrats on the cool find! You're going to love it. Coal is like wood like wood is like toothpaste. You'll find you just can't compare the two. With wood if you add more wood, you get more heat, with coal if you add more coal you get more time. The amount of coal loaded into the stove has little or nothing to do with how much heat you get. Fill that bad boy up give it a try! You'll find you can keep a very low amount of heat for a long, long time.
I see someone mentioned you should get a CO detector or two.... that should read "You MUST get a CO detector or two". Every now & then a freak thing can happen and a coal stove can cause CO poisoning. It usually happens when the chimney get's clogged. Coal does not make any creosote, but it will fill a horizontal pipe with ash. After you have run the coal for a month, check your pipes for ash build up. By checking after 30 days you will know if it needs cleaning once a month, or once a year. Every stove is different, but it must be checked.
Best of luck!

That looks like a back vent (there also is a top vent model). They like to accumulate fly ash in the area behind the baffle. You can use an elbow out of the back of the stove and have to move the stove every time you need to clean out the flyash or you can install a tee with a cap on one end, you simply remove the cap and vacuum it out. I tried it both ways and found out the tee with cap is definitely easier for some reason.

Once again, thank you guys for your tips! I will definitely look into putting a tee with cap on the back instead of the elbow. Also, I noticed that the ceiling vents downstairs are directly under the baseboard vents upstairs; so, I guess I'll just make sure they are both open and let the heat rise.

Well, the Mark I is hooked up and the learning process begins =) I fired it up the first day and the kitchen was TOASTY...thermometer on the fridge said 90 , but with all of the air leaks in there it didn't seem that hot and was quite comfy where we are usually working. I will need to put some kind of heat shield on the front of the freezer though as it got hotter than I would like to see. The coal burned well all day but went out that night =( In the morning I found that the grates seemed to be clogged with ash. I keep seeing people talking about "shaking" it down, "raking" the coal bed, and such...is there a special dictionary with all of the coal burning terms in it In the previous replies to my posts, I was told that I should use pea, nut or stove...the place where I buy locally sells chestnut, which is what I am currently working with. Is chestnut the same as nut? I have had to almost completely close the damper on the ash door in order to keep really overheating; I do hear the air being sucked in while the coals are nice and hot, even with it nearly completely shut down. Also, at what point do I add more coal? Is there a general guideline, such as when there are 3-4 inches of coal left in the firebox? Are there special tools that you guys use, or do you just use the normal fireplace/wood stove tools.....sorry for the simple questions By the way, I am already planning on moving the Mark I into the living room, replacing the wood stove, to be my main heat source next year; will need to see if I can find a small stove for the kitchen.

Shaking is the physical act of using the shaker handle on the left side of the stove. Short choppy strokes are key here. Don't try to use the full stroke or you'll end up dumping the fire into the ash pan.

If you can open the intake know and keep an eye out for hot coals dropping down, you'll know when to stop when you see them.

Raking is getting up underneath the fire and breaking up the ash. If you can do it on a Harman, you're a better man than I. If I need to clear ashes, I go in from the top with a regular fireplace poker. Carefully, because coal fires don't like to be turned over.

Chestnut=nut. Any of the 3 common sizes will burn in the Mark, it depends on your personal configuration as to what burns best. Don't be afraid to experiment or even mix. I use stove coal but sometimes, if I want to cut down on the airflow, I'll cover the pile with a bit of nut. Or even pea in the spring.

I have a cheap stamped sheet metal fireplace shovel.

Don't be afraid to load that stove up. I throw coal in until a few pieces start falling out and then I know it's full. Not recommended, but it's working for me.

Another thing I have been doing this year is to take the ash pan out. Seems to help me be more consistent.

If you think of a coal stove as a "breathing" device, then the air under the fire is the lung. And just like you, the larger and clearer the lung, the easier it is to run. I find the pan acts as a baffle to airflow. Especially the front as it is right behind the air intake. I shake the stove, then take the pan out and slide it under the stove to cool off. The next day, I throw the ashes in the trash and shake/load the stove again.

You want to load the stove, at least at this point, when you still see black on top of the pile. If the whole pile has gone gray between tendings, you should probably do it more frequently. Not that all gray is a bad thing, but as a new coal burner, you need to learn just how far you can push things.

Hisarrows wrote on 12/11:
Also, at what point do I add more coal?

This varies from stove to stove and your daily schedule. A coal fire has three stages of life. Stage 1 it will build rather quickly and after a few hrs will completely consume almost every piece of nut coal in the box. Stage 2 will be the warmest as the fire consumes coal and will be bright orange. This stage will last 6 to 10 hrs depending on whether you let the coal simmer or if you fire it fast in order to create more heat. Stage 3 will begin to occur as the ash begins to build from the bottom up. The temperature will also decrease during this period. Ash will also show around the edges of the firebox. If you look directly at the top layer of coal you will see what appears to be crushed ash still bright orange just under the top layer. This is when you know the fire is getting low & it is time to reload. I recommend you reload first, leave your damper open for 10 mins & let the new coal ignite before shaking.

You can reload at anytime if you schedule takes you away from home. I do not agree with the consensus opinion, just fill it to the top. If you do this especially in a hand fired, you will create more heat than if you only filled it half way during the 2nd stage. So if you want less heat, try a partial load but be prepared to check & add more often.

A Harman hand fired coal stove has the ability to *simmer*. In my opinion and from my testing using multiple thermometers, this is the way to receive the most efficient heat from your stove & coal. If you burn hot & fast, much heat will be lost in the flue gases. If you simmer, you can actually have a lower flue temp than your main heat output temps. The baro is important for some folks but I find it most effective simply to control your draft in an automatic way ( to an extent ) as ambient & local weather conditions change. i.e. high humidity vs cold dry air or wind. I manually control the damper. My baro remains closed much of the time. But everyone's setup has slightly different characteristics

trainingHisarrows wrote: I keep seeing people talking about "shaking" it down, "raking" the coal bed, and such...is there a special dictionary with all of the coal burning terms in it

There is a knowledge base link in the very top bar of the forum page. Click on it to find out some of the terms used here. This is continually evolving and definitions are being added and refined. If it isn't clear enough simply add to the entry.

For those in the "know" consider this a friendly reminder to take a minute and add something to the knowledge base for others to learn from.

Well, I now know where I have been making quite a few mistakes...trying to stir up the fire like I do in the wood stove being a large one I had figured that "shaking" was working the lever, but kept getting pieces of coal stuck between the grates. I'll try smaller shakes, and perhaps not shaking as often; I need to get out of the habit of messing with it all of the time like I do with the wood. I also learned a valuable lesson in patience tonight when I tried to rush the fire and smothered it...several times...and when I got it to start burning it kept going out again...my chimney was stone cold and would not draft, the high winds blowing back down weren't helping anything. Finally admitted defeat and started from scratch with a nice hot wood fire to heat the chimney and get a good coal bed, then added coal and am currently waiting to see if it will keep burning. I think it will, there is plenty of orange with blue flames on top. I once again thank all of you for your patience and input.

I only shake once every 24 hrs. Whether you can do the same or not, will depend on the quality of your coal. If it's particularly "ashy" coal, the excessive ash buildup will snuff the fire out long before you hit 24 hours. Cranking the stove all day will do the same. Draft will play into this as well ( i'm sure that was mentioned before).