New Here, Have a Few Q's

OK, here's what I have and what's going on with it. We have a refurbed Harman Mk 3 installed in the basement, with about 20' or so of triple wall chimney and PLENTY of draft.

The stove was missing the gasket around the ash door, which I installed. I misread the parts list and removed the gasket around the glass on the loading door. It heated like crazy and went thru coal like crazy as well. I'm burning Meadowbrook stove coal with a bit of chestnut and rice from the same mine mixed in. I found out about the door glass gasket, and installed one. when fired in that config, the fire went out very easily and seemed to fill up with ash very quickly and extinguished itself. I removed the gasket along the bottom edge of the glass only, reset the baro damper, and installed an MPD. I have a Bacharach combustion test kit and have yet to use it. I have about .06 to .07 draft with the MPD open. I run it with the MPD at about a 45* angle and the air intake spinner about 2 turns out.

I still run into problems with the fire choking up with ash and going out. When I shake it, very frequently the ash gets hung up in the fire and won't shake out. I have taken to stirring the fire with a poker ans shaking it again to get the ashes to fall, and I shake until I can see the glow from above in the ash pan.

I've used about 3/4 of a ton of stove coal so far, which seems like a lot. How is my consumption rate and operational plan? We're heating a 2k sq ft 2 story plus the basement.

Any comments welcome. This forum has been quite an education, thanks to all who post here.

Ops164

The rice may be part of the problem...
Two turns out with stove seems excessive...

Try burning just nut coal, try getting half a ton of Blaschak in Bags.
Partially burnt coal is usually the fault of the coal, not the stove.

Greg L

Rice doesn't burn well in a handfired. Rice is good in a stoker.

Welcome to the forum!!

The first thing I noticed is that the glass is only supposed to have the gasket on the sides, maybe wrapping around the corner about an inch at the most. If I understood correctly I think you have the gasket on the top and sides.

Two turns out on the spinner is about as hot as I would ever run mine and that was when it was very cold. Most times I had it open 1 turn.

Rice coal will clog up the air getting through the coal bed, I only ever burned nut in mine, others here also burn pea to get a longer slower burn than with the nut. Stove will tend to burn hotter and faster than nut because of the easier air flow through the coal bed.

If you are getting ash hung up in the fire box I would first check to make sure the space between the "fingers" on the shaker grates are clear. Rice coal that didn't burn all the way up may have clogged some of that space preventing ash from dropping effectively. Then I would say to make sure you are shaking vigorously enough. It is a tricky process to get the hang of, shaking hard enough and long enough without dumping the fire. We have all probably dumped a fire or two. You should see some hot coals drop through and a good red glow evenly across the ash pan indicating most of the ash has been cleared. I would recommend shaking with the ash door closed and then opening it to see the red glow. I always would get fly ash coming out if I shook it down with the ash pan door open.

I only had to use the poker about once or twice a week to scrape along the front of the firebox against the firebrick to clear the ash there. It would not shake out from across there very well. The rest of the bed would clear pretty well. Maybe once a season I would have to let it go out so I could clean off the top of the baffle plate and behind the firebox of fly ash and then I would clear out the bigger clinkers that would accumulate and not break up. The amount was a result of how hot I had been burning and the coal quality, sometimes more, sometimes less.

Depending on how much you have the stove running, I don't think 3/4 ton is very much coal to have burned so far. There is a thread on here talking about how much people have burned so far and you are not out of whack with what is listed there. In fact you are probably on the low end, but you may not be as far north as some and maybe haven't been burning the stove 24x 7 like them.

You'll get it tweaked correctly with a little trial and error from suggestions made here. Each set up has it's own personality and sweet spot so don't get discouraged.

I agree, the rice isn't helping a thing. Coal is not like wood. Wood will burn any old way, but when burning coal you have to play by the rules, and coal sets the rules. It is finicky & likes things just right. Any deviation from perfect conditions will lead to a less than perfect experience. From what I read I see three things you've done that deviates from perfect....oops....four. 1: Wrong fuel mix. Use no rice. Most people would be using nut in that stove, but some might use stove or pea, but rice is for stokers only. 2: Never stir a coal fire. Shake, or poke/slice from below, but never stir. 3: Changed gasket placement. The stove is designed well, replace to stock gasket configuration. 4: Not maintaining correct draft. Install a barometric damper & set it with the draft gauge from the Bacharach kit. You will then have a steady, known, draft. As it is now your draft changes as the temp & wind change.

As for burning 3/4 ton, we need more info. Was that this year? This heating season? This week? LOL Awwww, I'm pickin' on you, but we do need more into. I'm going to guess you have used some extra and will see more efficiency once you get into the rhythm .

Two turns and a 45 on the MPD is moving lots of air. With these settings are you running up in the 500 range? You really cannot expect it not to ash over in 8 hours or so if you are pushing that hot. What temp is your stove running like this, what is the draw once it settles in for the burn, and what is the manometer reading?

Are you filling the stove up to the point that the coal is slightly above the top of the fire brick and you absolutely cannot get any more in along the front edge where the brick is shorter? If not, you are not putting in enough and that is why you are not getting long burn times (combined with too much air). To get idle burns 200-25 on the stove,when it is warmer, you should be able to run down to 1/2 or 1/4 on the primary air, but you will need to open up the MPD to do these low and slow burns.

Stop mixing rice coal in. You do not need it, and it could well be part of the problem. You should have plenty of fines in either straight stove or a stove/nut mix. Personally I have run Blaschak in my MKII, and I was not impressed, especially for the price. There is a local supplier around here who has better stuff for less money. The Blaschak had plenty of fine stuff mixed in with it. If you are close and have the truck or trailer consider going to the UAE mine and picking up what you need.

If all you have used so far this year (depending on when you started )is 3/4 of a ton, you are either doing very very well, or not putting in enough coal. Personally I have already gone through a little more than 1 1/4 tons in the MKII, and this has been a much warmer winter than last year. On a cold winter like we had last year, you can easily expect to use 3 tons or so.

The factory design on the front fire brick is a problem on the MKII and MKIII. The coal along the front edge is much shallower than the rest of your coal, hence the front edge burns out first and ashes over, messing up the draw for the rest of the coal. If you can make the brick in the front higher it REALLY REALLY helps. This was what I did with mine, and you can do the exact same thing with the MKL III

Fire Brick Changes to My Harman MKII

Freddie is right. Never "stir" a coal fire. You're just mixing the ash in with the coal and makig it harder to get out. If you have to poker it, gently push on the middle of the pile. You'll see it collapse. Then leave it alone till your sure the coal on top is fresh and burning, (good hot temp) then shake it out. Skip the rice coal for sure. That's like adding fines. You're just blocking the air paths and thats why you have that much primary air to maintain. Go with nut alone and see how that does for you. I'm willing to bet it's just fine.

OK, here's what I have..

.05 draft on the baro alone (thought I mentioned that, sorry) and .03 with the MPD at 45*. Temp rise on the stack is about 350*, and I got only 4* CO2. Effiecncy is about 66 to 70%. We did dial back on the air intake and these readings were at about 1.5 turns open.

I have taken to shake, poke the fire where stuff isn't falling, and shake again until I can see the red glow from the fire above.

I'm surprised at the CO2 reading, as low as that is sounds like maybe too much secondary air over the fire? Too much primary air usually will run a very high stack temp along with low CO2, at least on oil fires.

How's that sound? Is this where I should be with the craft, CO2, and stack temp?

Ops

Ops, Why run any over the fire air? Your using anthracite yes? It only wants under the bed (primary) air. The only time I ever run the secondary (overfire air) is after a big reload to burn off volitiles for 15-20 min or, if I want to slow the the fire sort of like a baro bi-passing air. If you are burning bit coal excuse me, but if anthracite, run with only primary air from below. As far as stack temps, it depends. You haven't stated what the stove temp is, but my stove, once it's up and cruising, stack temps (at thimble) are about 1/3rd of the stove temp.

Meadowbrook Coal sells anthracite, it is the farthest SW end of the Southern Field in upper Dauphin Co. I don't have a means of measuring stove surface temp yet. We initially ran the stove with the entire glass panel gasketed and the fire would self extinguish. I read somewhere in Harman's literature that the glass wasn't fully gasketed so we ran it without any. We went thru way too much coal and could not control the fire, so I removed the gasket from the bottom. It seems to work the way it is, and it is my understanding that coal needs both primary and secondary air for a full burn.

i used to be an oil burner mechanic and understand something about combustion, just not much about solid fuel. I am getting an education..

Ops

Bein an old farmer, I'm not sure what you mean by primary & secondary--I do know that coal needs under(bottom) draft not over (top) draft. As in none!! Forget all your oil burner mech. stuff, just like many of us had to forget all our wood burning knowledge. This is a whole different ball game. The most impt. things I found, was taking suggestions from fellow FORUM members on how to do this properly.

Ops,

You cannot "adjust" the over the fire air on a MK II or III. You have done part of what the factory intended by removing the gasket for the botttom of the glass. Is your stove the single piece of glass or the 3 pieces? Gasketing the glass is different for these two doors. 3 pane is the older stoves, and single pane is the new stove. I just went through this with a Harman dealer who checked at the factory for me. The single glass pane, you are to only have gasket material on the sides of the glass, leave the top and bottom gasket less. On the 3 pane, you only leave the gasket off the bottom as there are 3 small slots in the door that also allow over the fire air.

Are you loading the coal to the top of the fire brick? If not you need to be.

The temp of 350, is that with a probe thermo going into the stack. If it is that is fine. Flue gas temps will pretty much match your stove temp when you get the magnetic thermo for the side of your stove. During a reload though, you will want to let the flue gas temps get up higher, pushing 1000. If 350 is with a stick on thermo on the outside of the stack, that is rather high for a steady burn.

Harman Mark series will eat some coal when you are asking it to put out real heat. The MK II holds almost 50 pounds with the modification I made to the front brick. I would think your MK III will hold more like 70 when first loaded up. At Idle temps you will not burn that much, but when pushing stove temps 452-500, expect to use 50-70 per day. At least this has been my experience.

Bear, so far we seem to be in the same place. It is the later model with the single panel of glass, and thank you for your research on the door gasket. I have to wonder if removing the top gasket would add too much secondary air to the reaction, low CO2 usually means too much air. I am spot on as to consumption and I do load it up when I load it. It will go for 24 to 30 hours on a low fire with no problems.

Fred, "primary air" is the air that mixes into the fuel prior to combustion, or under fire air. Secondary air mixes in above the fire, and apparently Harman thinks it necessary. Coal is not all that different from oil, it is a hydrocarbon although anthracite has VERY little hydrogen. the flames on the fire bed are volatile gases burning off, and I didn't get the blue flame with the glass gasketed all the way and as in the OP, the fire would go out very easily.

Also part of the problem is the fact that the stove is in the basement. It's about 90* down there, and we don't get enough convection up the stairway to move the heat up here. I did install a bath vent fan above the stove and run the discharge hose into the first floor return plenum. I need to come up with a better way to move the warm air up from the basement. It seems I more or less blundered into semi-correct operation, with the exception of the low CO2 reading. I'll keep experimenting.

Thanks guys.

Ops164

Ops,
This is my first year burning coal. I have a very similar set up, Mark III in the basement and aprox. 1900 sq. ft above. In your last post you mention air movement, when I got this the upstairs stays 72-75* and the basement stays at 84-90*. These fellows will talk about registers (open vents in floor) between the basement and living area. I have 3 and keep the stairway doors up top open. With an incense stick I can watch the air move up and down the stairwell, cool! Depending on the coal I'm burning, My MPD is almost closed and the screw air control is 1.5 and 2 turns open. I burned wood for nearly 30 years in GA, I had to unlearn some things and play with it a little bit. The guys and gals here know whats going on. You will get it.
Cracker