Idling the Mark II
- lowfog01
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- Location: Springfield, VA
- Hand Fed Coal Stove: Mark II & Mark I
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Hi everyone,
I'm looking for answers about idling my Harman Mark II. I can't seem to get it to idle below 300*. The air intake is at one complete circle and then back an eighth of a turn. It starts to go out and we have to refresh it and up the air. I have the baro on and it seems to be working well. I was hoping to set it with the manometer this week end but the warmer weather may preclude that. We'll see. I know from reading various posts on the forum that some people can get their stove temperature way down. What's the trick? May be I'm as low as I can get with the Mark II. Any thoughts will be greatly appreciated. Lisa
I'm looking for answers about idling my Harman Mark II. I can't seem to get it to idle below 300*. The air intake is at one complete circle and then back an eighth of a turn. It starts to go out and we have to refresh it and up the air. I have the baro on and it seems to be working well. I was hoping to set it with the manometer this week end but the warmer weather may preclude that. We'll see. I know from reading various posts on the forum that some people can get their stove temperature way down. What's the trick? May be I'm as low as I can get with the Mark II. Any thoughts will be greatly appreciated. Lisa
- PC 12-47E
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Hi Lisa, Try using the dead coal in the front portion to your advantage. All the Harman hand fired stoves get the dead section by the loading door. Let that coal die and do not poke that section. Use the back section to add coal and keep the fire going in the back of he stove. Also you may be able to reduce the size of the firebox. My Harman SF-250 has 5 grates and we are reduced to 3 grates at the moment. This cuts down on the coal and heat output. Hope this helps.
RS
RS
Probably the most difficult thing to do with a hand fired stove is to get it to idle real low (usually Fall & Spring, during the day when it's warm out & the draft is poor) but not let it go out. Some people do it by reducing the size of their fire box so there' less coal burning (for a cooler stove output but that shortens burn times too) while others reduce the amount of coal in the stove, while other just close off most of the air. Keep in mind, when burning cooler fires you will always be right on the edge of losing your fire completely. One "Toy" I highly recommend is this http://www.smarthome.com/3219/Redi-Chek-ET-73-Rem ... ter/p.aspx remote smoker thermometer which will remotely alarm if your fire gets to hot OR TO COOL. (I keep the receiver on my headboard & it has saved many fires for me that I would not have gotten to in time to open the ash door & save it. I keep the low temp alarm at 125*)
- PC 12-47E
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Hi Dev, I am not sure that reducing the firebox shortens the burn time. The depth of the coal bed determines how long the fire will burn at a specified air setting.Devil505 wrote:Probably the most difficult thing to do with a hand fired stove is to get it to idle real low (usually Fall & Spring, during the day when it's warm out & the draft is poor) but not let it go out. Some people do it by reducing the size of their fire box so there' less coal burning (for a cooler stove output but that shortens burn times too)
Our stove has burned 19.5 hours on a reduced firebox without adding or shaking.
RS
Hmmmm...You may be right......I always figured the lower volume of total coal would shorten burn time??PC 12-47E wrote:Hi Dev, I am not sure that reducing the firebox shortens the burn time. The depth of the coal bed determines how long the fire will burn at a specified air setting.Devil505 wrote:Probably the most difficult thing to do with a hand fired stove is to get it to idle real low (usually Fall & Spring, during the day when it's warm out & the draft is poor) but not let it go out. Some people do it by reducing the size of their fire box so there' less coal burning (for a cooler stove output but that shortens burn times too)
Our stove has burned 19.5 hours on a reduced firebox without adding or shaking.
RS
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Have you shut off the blower?I can't seem to get it to idle below 300*.
I can get the stove to putt along at 225*!
Killing the blower will put more heat up the chimney and keep the draft going.
I have a 8" Metalbestos 15' chimney that will keep the fire to 65* outside temps.
Last edited by CapeCoaler on Fri. Mar. 06, 2009 7:25 pm, edited 1 time in total.
Try this thread Lowest Warm Weather Stove Temps?
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Maybe you only THINK it is starting to go out. Seriously. In warm weather (50-60 degrees) last Spring, I could easily idle my Mark I for 24 to 30 hours at slightly less than 1/2 turn open. Yes, it looked like it was going out, but it never actually did. At first I was just like you, kept upping the air to refresh and save the fire. Then one day I WANTED to let it go out, so I left the air at one-half turn and just waited. Damned if it wasn't still burning 36 hours later, and I was able to revive the fire though it wasn't easy. All this time the stove pipe temp was about 100 degrees (above the baro).lowfog01 wrote:It starts to go out and we have to refresh it and up the air....
The only way you will know is to try it! Just set the air down low and resist the temptation to save it. Let us know what happens.
P.S. My technique -- don't know if it was necessary or not -- was this: Each night I would shake down thoroughly, reload, and give it lots and lots of air for awhile until I had the ENTIRE coal bed glowing red. Then I would shut down the air to 1/2 turn, walk away and REFUSE to worry about it for another 24 hours.
P.P.S. And never mind the baro. At those low stove temps and high outdoor temps, your draft will never be high enough to open the baro unless the wind blows.
Last edited by rberq on Fri. Mar. 06, 2009 7:00 pm, edited 1 time in total.
Excellent point! Even if your fire gets very low, you'll still be able to refresh it (at night when it gets colder) by opening your ash door & leaving it open for however long it takes. (Obviously your fire must have some little life left in it & the real danger is opening the ash door & forgetting to close it. I use an egg timer that I'll carry with me & set it for 10 minute increments)rberq wrote:Maybe you only THINK it is starting to go out. Seriously. In warm weather (50-60 degrees) last Spring, I could easily idle my Mark I for 24 to 30 hours at slightly less than 1/2 turn open. Yes, it looked like it was going out, but it never actually did.
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Key thing is to wake it up for the cooler night time.
You need the heat at night and better draft too.
Then just let it coast along during the day.
You need the heat at night and better draft too.
Then just let it coast along during the day.
- Razzler
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I can idle my stove down to 150* (that's over the fire temp) you can just about keep your hand on the side of the stove. When it's really low like that and you look in the stove you would think it was out, you have to look real hard to see a orange glow from spots about the size of a pencil eraser maybe four or five across the top of the bed. That's with the draft knob opened 1/16 of a turn. The only way to see how low you can go is to try it. Set it leave it for a day then the next day go a 1/4 turn lower and so on.
- lowfog01
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Rberq wrote "Maybe you only THINK it is starting to go out."lowfog01 wrote:It starts to go out and we have to refresh it and up the air....
I have been thinking along those lines, too, so last night I set the draft way low (for me) - a 3/4 turn. I also used a pea/nut mix of coal. When I got up this morning the stove was simmering away at 200* stove top and 125* after the baro and most of the coal was still untouched. It was 45* outside last night and at 200* the stove kept the house a comfortable 75*. After 10 hours the fire obviously had a good bed of red hot embers and did not show signs of going out. I would think that if I wanted to I could refresh it and get a roaring fire going with little trouble. After the sun comes up I'm going to turn the draft down to 1/2 turn and see what it does. I think the trick is going to be not touching it when I think it looks ready to die. This will be hard for me. My husband always says I've never had a microwave oven that's fast enough! Patience is not my strong suit.
I'm also going to try to implement using the dead coal zone that the Mark II gets up front as a natural firebox reducer. I have been thinking how to reduce the firebox on the Mark II but couldn't get past the shaker system. I'll let you know how things work out this evening. Thanks to everyone for their ideas and input! Lisa
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lowfog01 wrote:200* stove top and 125* after the baro .... the trick is going to be not touching it when I think it looks ready to die. This will be hard for me .... I'm also going to try to implement using the dead coal zone that the Mark II gets up front as a natural firebox reducer.
It will make you upset to watch the coal, so look only at the stove pipe temperature. As long as that holds up, you know the fire is OK. My rule of thumb -- instructions to my wife when I went off to work -- were to open the air a little bit if stove pipe temp dropped below 100 (after the baro). Your stove is the next size up from mine, but I'll bet the spin draft is identical, so maybe my 1/2 turn equates to your 3/4??? Or maybe not.
I don't know what to say about reducing the firebox. I have read on this forum that having a large mass of coal burning works best, even if it's burning at a very low rate due to low air input. Be careful about trying both experiments at once -- low air AND reduced firebox -- because then if it goes out you won't know which one caused the failure.
- lowfog01
- Member
- Posts: 3889
- Joined: Sat. Dec. 20, 2008 8:33 am
- Location: Springfield, VA
- Hand Fed Coal Stove: Mark II & Mark I
- Coal Size/Type: nut/pea
Good point! Thanks for the advice. Lisarberq wrote:lowfog01 wrote: Be careful about trying both experiments at once -- low air AND reduced firebox -- because then if it goes out you won't know which one caused the failure.
- grizzly2
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I have read on this forum that having a large mass of coal burning works best, even if it's burning at a very low rate due to low air input.
Is it a large mass of coal, or a deep bed of coal that promotes a good burn
Is it a large mass of coal, or a deep bed of coal that promotes a good burn