Harman Mark 3

godsgirl81 · Post by **godsgirl81** » Mon. Jan. 10, 2022 8:41 pm

Hi, I recently bought a Harman Mark 3 coal stove that was totally redone. They actually did an incredible job on the restoration (sandblasted, repainted, new shaker grates, glass, fire brick ect... So the stove would be hard to tell apart from a new one. I been running it for about 2 weeks heating 2500 sq ft very well. At first I had some issues working the shaker where id get coal stuck and lost my coals twice but since figured all that out, no biggy. My question is do any of you have a Harman mark series and if so what if any issues have you had with it over the years, how does it heat ect..
After using it the past two weeks burning nut i'm very pleased as it warms the entire building to a comfy 74 degrees even on days when it gets down below 20 degrees. I live in the coal region of PA so good Anthracite is available for $165 a ton right near my house but im curious what kinda coal you had the best results with? I thought of getting some stove coal but not sure its needed. Sometimes I started mixing nut and pea together which really seemed to work even better than just nut but im curious what you all burn ect...
Thanks

Arlon · Post by **Arlon** » Mon. Jan. 10, 2022 11:06 pm

Greetings, I've had my Mark III for two years and do like it, although I still miss my Estate Heatrolla. The few things I don't care for are; as you said it's easy to dump the fire when shaking, the lip at the opening for the ash pan, and an issue I had with the glass in the door.

The shaking the ash you'll get use to. If you have a chunk REALLY stuck, let it go and walk away. Most times I find when I come back the chunk has burned and the grate will free up. Because of the lip at the ash pan I found it easier to remove the pan and just shovel the ashes into a metal coal bucket.

Now for the glass in the door. Mine was refurbished also. Unfortunately the monkey who refurbished it REALLY screwed up. Mine is an older model and the gasket goes totally around the glass. There are 4 studs that hold the glass frame. When I got my stove I could not keep it running for more than a day or two. It was like it was banked all the time. One night I added coal and (thank God I had gloves on) the glass just slid right out of the frame, but I was able to catch it. What I found was, the studs must have broken out and the guy who refurbished it just used JB Weld to replace the. The epoxy, of course, could not take the heat and gradually left loose. It was an easy fix by drilling out the studs and just replacing them with bolts and nuts through the door and frame. Ever since it has run like a top.

I was using pea/nut mix, but just recently went to all nut. I find I could hold it longer and lower with the mix then I can with the nut. I have a manual damper in my stove pipe and between that and the draft control on the bottom I can get 12 hours easy without having to add coal. Just make sure you keep a DEEP bed of coal, but don't go over the fire brick. I put a whole coal bucket on each time.

When I add coal I draw up the fire, then shake the ash. I add the coal and wait for the blue dancers (the blue flames that is the coal gas burning off) the close the draft and let it go.

One more thing. Don't open the draft and forget about it. I've done it twice and the temp reached close to 500 F. I now set an egg timer for 15 minutes when I'm drawing up the fire.

waytomany?s · Post by **waytomany?s** » Tue. Jan. 11, 2022 7:00 am

Arlon wrote: ↑
Mon. Jan. 10, 2022 11:06 pm
Greetings, I've had my Mark III for two years and do like it, although I still miss my Estate Heatrolla. The few things I don't care for are; as you said it's easy to dump the fire when shaking, the lip at the opening for the ash pan, and an issue I had with the glass in the door.

The shaking the ash you'll get use to. If you have a chunk REALLY stuck, let it go and walk away. Most times I find when I come back the chunk has burned and the grate will free up. Because of the lip at the ash pan I found it easier to remove the pan and just shovel the ashes into a metal coal bucket.

Now for the glass in the door. Mine was refurbished also. Unfortunately the monkey who refurbished it REALLY screwed up. Mine is an older model and the gasket goes totally around the glass. There are 4 studs that hold the glass frame. When I got my stove I could not keep it running for more than a day or two. It was like it was banked all the time. One night I added coal and (thank God I had gloves on) the glass just slid right out of the frame, but I was able to catch it. What I found was, the studs must have broken out and the guy who refurbished it just used JB Weld to replace the. The epoxy, of course, could not take the heat and gradually left loose. It was an easy fix by drilling out the studs and just replacing them with bolts and nuts through the door and frame. Ever since it has run like a top.

I was using pea/nut mix, but just recently went to all nut. I find I could hold it longer and lower with the mix then I can with the nut. I have a manual damper in my stove pipe and between that and the draft control on the bottom I can get 12 hours easy without having to add coal. Just make sure you keep a DEEP bed of coal, but don't go over the fire brick. I put a whole coal bucket on each time.

When I add coal I draw up the fire, then shake the ash. I add the coal and wait for the blue dancers (the blue flames that is the coal gas burning off) the close the draft and let it go.

One more thing. Don't open the draft and forget about it. I've done it twice and the temp reached close to 500 F. I now set an egg timer for 15 minutes when I'm drawing up the fire.

The gasket is only supposed to cover the sides. The horizontal sides are left open for overfire air and as an airwash to keep the glass clean.

Arlon · Post by **Arlon** » Tue. Jan. 11, 2022 7:47 am

"The gasket is only supposed to cover the sides. The horizontal sides are left open for overfire air and as an airwash to keep the glass clean."

Waytomany, That's the NEWER Mark III's. Mine has an air vent directly below the glass that is cast into the door. Common mistake but something that needs to be checked. My old one, according to Harmon, has the gasket around the entire glass.

rberq · Post by **rberq** » Tue. Jan. 11, 2022 3:55 pm

godsgirl81 wrote: ↑
Mon. Jan. 10, 2022 8:41 pm
I thought of getting some stove coal but not sure its needed. Sometimes I started mixing nut and pea together which really seemed to work even better than just nut but im curious what you all burn ect...

I used stove coal for awhile in a Mark 1. It burned just fine and I liked it better than nut. So I think it should work well in your much bigger Mark 3. I stopped using stove coal because it didn't pack together as much as nut, due to the bigger pieces. I found that I could get 15 percent less coal, by weight, into the stove, which reduced my burn time by 15 percent, from 12 hours down to 10. That did not work well with my away-from-home work schedule.

waytomany?s · Post by **waytomany?s** » Fri. Jan. 14, 2022 12:20 pm

Arlon wrote: ↑
Tue. Jan. 11, 2022 7:47 am
"The gasket is only supposed to cover the sides. The horizontal sides are left open for overfire air and as an airwash to keep the glass clean."

Waytomany, That's the NEWER Mark III's. Mine has an air vent directly below the glass that is cast into the door. Common mistake but something that needs to be checked. My old one, according to Harmon, has the gasket around the entire glass.

Hey, learn something new every day. Ill have to see if I can find a picture. I almost think I would prefer a setup like that.

BlackBetty06 · Post by **BlackBetty06** » Wed. Jan. 19, 2022 5:53 pm

I ran a Mark 3 for 16 years growing up. I have a 50-93 currently.

The 50-93 is much faster tending a due to the hopper.

The Harman is built heavier all the way around. The ash door on the 50-93 is flimsy sheet metal. Drop the ash door on the mark 3 and it will break your foot. The Harman grates in my personal opinion are superior to the Hitzer. They always cleared evenly and don’t have a bar running through the middle of them. That said the Hitzer grates work good enough and I just poke where it doesn’t clear right.(partially because area under hopper will clear faster). The Harman has secondary over fire air and I never got a puff back once blue flames were established. This is my biggest complaint on the Hitzer. Why you would build a stove with ZERO secondary air is beyond me. If I load it up with a lot of fresh coal and am running the stove low, I have to keep the load door cracked till blue flames establish, other wise it will puff and blow a nice ash cloud out the bi metallic. I could idle the harman to where it looked like it was out due to the secondary air. Hitzer not so much.

All in all they both heat great! No complaints on either one. The speed of tending the hitzer is really nice for my point in life right now. The hitzer was also more economically priced. The bi metallic thermostat is also a nice feature.

In 16 years with the Harman, the only thing replaced was a piece of door glass and the gaskets once. I’m on season 7 with the hitzer and nothing replaced yet on it other than the hopper lid gasket.

If I was retired and had time to fiddle, I’d run the Harman. Better fire view and has secondary air. For the working man, speed tending is really nice on the hitzer.

Make sure you vacuum out the top of your baffle on your mark3 from the flue collar, fly ash will build up there and can cause your baffle to warp.

Hoytman · Post by **Hoytman** » Wed. Jan. 19, 2022 7:08 pm

For what it is worth...
Hitzers do have secondary air. Just not in the same sense as the Harman or even my double door 354 with door spinners...but it is there none-the-less.

I think those puff backs you and others get is due to something else that we haven’t put out fingers on yet.

Post by **Lightning** » Wed. Jan. 19, 2022 7:15 pm

Hoytman wrote: ↑
Wed. Jan. 19, 2022 7:08 pm
Hitzers do have secondary air. Just not in the same sense as the Harman or even my double door 354 with door spinners...but it is there none-the-less.

If yer referring to the air wash its unregulated and not adjustable... and it may or may not be enough to dilute the gases till they are ready to safely ignite and stay lit. Although, that style of secondary air can be tweaked a little by draft pressure. Personally I'd prefer an independent secondary air control

BlackBetty06 · Post by **BlackBetty06** » Wed. Jan. 19, 2022 7:29 pm

Hoytman wrote: ↑
Wed. Jan. 19, 2022 7:08 pm
For what it is worth...
Hitzers do have secondary air. Just not in the same sense as the Harman or even my double door 354 with door spinners...but it is there none-the-less.

I think those puff backs you and others get is due to something else that we haven’t put out fingers on yet.

The little whiff that may occasionally sneak up by a fire brick is completely useless in my opinion. Real secondary air like almost every coal stove on the market has in one shape or form would eliminate a lot of problems. Obviously most that have these stoves it works good for, but I’m one of the odd balls that it doesn’t. When the flap would close my chimney would completely stall and fill my house with CO. Sadly I had to put a stainless liner in to help correct it. (Flue top temps went from 45 degrees pre liner to 146 degrees) prior to the liner if I would leave load door latch “hooked” but not secure there were no problems. Also adding a barometric damper gave the chimney somewhere to draw some air from when the stove would completely slam shut. Ash door vents didn’t help either unless open enough to create a good burn. For me the puff cause is easy. If stove is at temp and bi metallic is closed and I dump a bucket of coal in. I have 30 pounds of fuel starting to off gas from the heat with no oxygen and no airflow through the stove. Stove finally cools enough and bi metallic opens, oxygen flows in and the dust flies out lol. Still a pretty good stove in my opinion. With one simple addition of secondary air this stove would be awfully hard to beat. But In my opinion the lack of secondary air makes the Mark series a better coal burner. (Not to be confused with easier) No hard feelings to the hitzer crowd as I’m one of them. Just my opinions on running a Mark 3 and 50-93

Hoytman · Post by **Hoytman** » Wed. Jan. 19, 2022 7:53 pm

Under fire primary air slips past the bricks and exists above the fuel load and becomes secondary air. It’s just not secondary air in the traditional sense most think of. It certainly isn’t adjustable.

I can easily reproduce this in my 354...which uses the identical grate frame, grates, and brick retainer. I can see no reason the same wouldn’t happen in 254 and the 30-95 even though there are slightly different inside. Air still should slip between the skin of the stove and the grate frame.

Keep in mind these parts must remain somewhat smaller than the stove in order to remain replaceable. This reduction in size makes for gaps and gaps make for air slipping past the grate frame and the fuel load becoming over the fire air...secondary air. It’s there by design.

I wish I knew how to post a video because I would post it.

I have video of blue flames emitting from places other than directly over the fuel load indicating air slipping between the steel skin of the stove and the bricks. This happens in the back, the sides, and the front.

I even have video of blue flames emitting between my front bricks and the door frames while at the same time being lower than the fuel load and/or the top of my front bricks. Some of you may recall that my front bricks are not cut. They are in fact full size bricks laying on their side.

Let me see if I can post a picture of where I am talking about.

Hoytman · Post by **Hoytman** » Wed. Jan. 19, 2022 7:59 pm

BlackBetty06 wrote: ↑
Wed. Jan. 19, 2022 7:29 pm
The little whiff that may occasionally sneak up by a fire brick is completely useless in my opinion. Real secondary air like almost every coal stove on the market has in one shape or form would eliminate a lot of problems. Obviously most that have these stoves it works good for, but I’m one of the odd balls that it doesn’t. When the flap would close my chimney would completely stall and fill my house with CO. Sadly I had to put a stainless liner in to help correct it. (Flue top temps went from 45 degrees pre liner to 146 degrees) prior to the liner if I would leave load door latch “hooked” but not secure there were no problems. Also adding a barometric damper gave the chimney somewhere to draw some air from when the stove would completely slam shut. Ash door vents didn’t help either unless open enough to create a good burn. For me the puff cause is easy. If stove is at temp and bi metallic is closed and I dump a bucket of coal in. I have 30 pounds of fuel starting to off gas from the heat with no oxygen and no airflow through the stove. Stove finally cools enough and bi metallic opens, oxygen flows in and the dust flies out lol. Still a pretty good stove in my opinion. With one simple addition of secondary air this stove would be awfully hard to beat. But In my opinion the lack of secondary air makes the Mark series a better coal burner. (Not to be confused with easier) No hard feelings to the hitzer crowd as I’m one of them. Just my opinions on running a Mark 3 and 50-93

I’m not disagreeing with any of that. What I am referring to certainly is NOT adjustable and I can see the benefits of having adjustable air.

I’m just pointing out that there is some over fire air that comes from below. I’m not sure any of the hopper guys have ever noticed this. I discovered it by accident really.

I have to wonder if the main difference to why hand feds don’t seem to have these puff back issues versus the hopper fed stoves is maybe caused by the fact that hand fed stoves need to be ramped quite a bit more versus feeding thru a hopper.

Anyone ever try cracking the load door before opening the hopper lid? Maybe this might help eliminate this issue. Of course, a secondary spinner or two might help as well.

Hoytman · Post by **Hoytman** » Wed. Jan. 19, 2022 8:07 pm

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I’m the middle picture you can see my finger is pointing to a weld on the stove. There is also a gap all across the front of the stove in line with my finger.

You can also see how I left my bricks uncut laying on their sides. When I close the door my door glass is actually even with the front lip of the stove. This allows the bricks to be seen behind the door glass. I have video of blue flames dancing between the glass and those bricks...below the front of the fuel load.

Hoytman · Post by **Hoytman** » Wed. Jan. 19, 2022 8:11 pm

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You can see the bricks thru the glass. I can produce blue flames there at will. When I do they also emit above the brick retainer between the bricks and the steel. Sometimes they are also not seen in those spots and none above the fuel load until later in the burn.

Hoytman · Post by **Hoytman** » Wed. Jan. 19, 2022 8:16 pm

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For less than $15 a spinner from a Hitzer 55 can get you adjustable over fire secondary air, for those that need it, or in my case, adjustable primary air through the ash pan door, which is why I bought it.