Puzzling Draft Problem

Felix the Cat
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Post by Felix the Cat » Wed. Oct. 22, 2014 6:37 pm

I have a Harman Mark lll hand fired coal stove. Double wall insulated chimney pipe. Stove has a barro dampner installed on the top of the stove. Stove burns excellent when its cold enough, mostly burn pea coal. Spring and fall gives me a hard time burning. Usually have to keep the ash pan door open with the barro dampner fully closed to keep a small fire burning. When I go to bed at night I close the ash pan door, and naturally the fire goes out. I do have a manometer installed I'm pulling around 4-5 on the meter. I figured i'd try a ad-1 draft inducer to help me in burning the unit during the spring and fall. I installed one on the stove above the barro dampner. Now with the ad-1 draft inducer turned on high and the ash pan door open and the barrow dampner fully closed the manometer reads 10, wow great draft, only 1 problem stove still doesn't want to burn. If I close the ash pan door, with the barrow fully closed, the manometer reads 18, wow really good draft, still 1 problem the stove still doesn't want to burn. I am really lost here, have no clue. Anybody have any ideas.

Any help or input would be greatly appreciated.


OK first of all I made a mistake on the draft numbers, numbers are not 4-5. My draft usuall runs around half of .10 thats 5 little Iines after 0. I don't know what the small lines represent, would that line represent .05 they give you no book with the manometer explaining what the lines mean. My stove burns at that setting all winter with no problems. Problem is this time of the year (shoulder time) the draft is not enough to keep the stove burning. Thats why I bought the draft inducer to give more draft. The draft inducer on high with the ash pan door closed will take the draft up to just about .20 this seems like alot of draft to me. And at this setting the fire still doesn't seem to want to burn. Maybe its to much draft and is sucking the fire out. I tried to turn draft inducer down on low and the fire goes out anyway. On low the manometer says .o8-.09.

Gaskets around both doors are new and not leaking, also did dollar bill test.

I start out with building a wood fire which doesn't seem to burn very well either (thats why I bought draft inducer), I thought it would help solve this problem once I get fire established with wood I will start adding coal and naturally the coal doesn't like to burn to well in the shoulder months I thought the draft inducer would help with this. I understand that the firebox has to be filled to the top. and that the stove should be raked at least once a day. I have been using this stove for 10 yrs now. Never had any problems with it. I am just trying to burn it a little more in the sholder months. Maybe the draft inducer is not the answer to my problem, I thought maybe it would help.

I burn nut coal and pea coal in this stove. I burned pea in this stove all last winter at 500 degrees, yes the pea coal does pack pretty good creates alot of ash, then the fire seems to want to die because its not getting enough of air. Maybe the nut might be the answer to that problem. I am using nut right now trying to get this to burn. The coal is good quality I burned it all last year.

Top of the baffles are clean, the jacket on the back of the stove inside is clean. I clean the stove myself and the chimney is clean.

Gaskets are on the sides of the glass.
Last edited by Felix the Cat on Wed. Oct. 22, 2014 11:18 pm, edited 2 times in total.

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Post by coalder » Wed. Oct. 22, 2014 6:49 pm

In all due respect, whatever you do, DO NOT!!! run with the ash pan door open!!! I am extremely suspect that the problem lies in the fact that you are burning pea coal. With this being the "Shoulder season", The draft on your chimney is minimal, and pea coal packs tighter then nut or stove coal, therefore restricting air flow. I would suggest that you get some nut and see where it goes. But whatever you do " DO NOT EVER" run with the ash pan door open.

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Post by michaelanthony » Wed. Oct. 22, 2014 7:39 pm

Ok first ditto^^^^ TWICE^^^^ Please do not play with fire you will get burned! I'm glad you are here to type Felix the Cat...ok you have 8 left. If I ran any of my stoves at that manometer reading with the ash pan open I would have a puddle of steel on my hearth. Oh and I would be taking a dirt nap. Have you changed the batteries on your C.O. detectors! I would negate some of the add on's in order to find the trouble, like aluminum foil over the baro and remove the draft inducer because you were pulling a (your words) 4-5. Check the gaskets, do the dollar bill test by closing the doors on the dollar bill and tug, if the bill slides out easily replace the gasket. Check you flue pipe at the breech the mano is measuring your chimney not the stove, oh and have you changed the batteries on your C.O. detectors!
Enough of my rant...after all that try larger coal than the pea as a matter of fact try some wood and see if it stays lit.

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Post by franco b » Wed. Oct. 22, 2014 7:57 pm

There is no way that the stove can lose that much draft through it.
The only possibility that I can see is that the draft is bypassing the grates. How this could be with a Harman I don't know, but it is not going through the coal.

Another possibility is that the coal is not completely covering the grates which again would bypass the coal. Pea coal wants at least 4 inch and better a 6 inch bed.

Assuming you start with a wood fire, how well does it burn? Do you then completely cover the entire fire pot area with coal once the wood is going well and is maybe half charcoal?

Is your coal a known good quality?

If one of these turns out to be the problem, then be aware your draft is much too high and you must lower it to .04 to .05 to avoid the coal burning like a blowtorch.

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Post by McGiever » Wed. Oct. 22, 2014 8:11 pm

No mater that is not very cold outside, you must, as *franco b* said, fill coal to top of bricks and from wall to wall and front to back solid with coal...this ain't wood here.

You need to study the beginners handbook.
Basics of a Hand Fired Coal Stove

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Post by Lightning » Wed. Oct. 22, 2014 8:33 pm

Are you shaking the grates thoroughly? There should be red embers falling into the ash pan at every shake down. Try shaking down every 12 hours just to be sure you are clearing ash properly. And as others have mentioned, fill it to the top of the fire brick after every shake down. Your coal layer should be 8 or more inches deep all the way around the fuel bed area.

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Post by SMITTY » Wed. Oct. 22, 2014 8:45 pm

Make sure you have 2 strips of insulation (rope gasket) on the left and right sides of the glass - that would be the only way excessive draft could bypass the fire .... but I doubt it would bypass that much, even with no gasket at all. It's normal for the top and bottom to have no gasket - this is to keep the glass relatively clean & cool, and provide a little over-the-fire air to aid in burning volatiles at startup/reload.

My chimney used to pull a .04, and I would have a hell of a time reloading while burning nut. Took quite a while for the layers to catch. If I were burning pea, it would never get going! I would have been better off burning stove ... but I've since moved on to a stoker boiler, and I ain't lookin' back! :D

Another thing ... make sure the top of that baffle plate, and down the back to the flue exit on the stove is CLEAR of flyash - LOTS of ash can accumulate there. If it hasn't been cleaned back there, that could be your problem. :idea:

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Post by dlj » Thu. Oct. 23, 2014 7:45 pm

I'm with Smitty with this one. The draft you are measuring is not going through your stove. You must have some kind of blockage.


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Post by davidmcbeth3 » Fri. Oct. 24, 2014 1:13 am

dlj wrote:I'm with Smitty with this one. The draft you are measuring is not going through your stove. You must have some kind of blockage.

That's my guess too ... a pain to track down sometimes ...

http://www.ebay.com/itm/USB-VIDEO-INSPECTION-Bore ... ls&vxp=mtr

Video inspection cameras are easily gotten today.

I always like to know .. not just base a conclusion on limited information.

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Post by freetown fred » Fri. Oct. 24, 2014 7:27 am

Personally, I'd get a few bags of NUT & give that a try. AFTER checking for any kind of blockage--put a match up by your outlet & if the flame is sucked in, go with the NUT experiment.

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Post by blrman07 » Fri. Oct. 24, 2014 8:30 am

Where are you located? There might be a forum member nearby that can come by and lend a hand.

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Post by ddahlgren » Fri. Oct. 24, 2014 11:46 am

Why not take a draft reading at the ash pan door?

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Post by Dallas » Fri. Oct. 24, 2014 4:24 pm

I'd open a window near the stove to see what effect that has on the burn. Have you closed anything off? The stove may be starving for combustion air.

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Post by Lightning » Fri. Oct. 24, 2014 7:39 pm

I saw your edit in your first post. Please use the "reply" Button to add another post so people will see the new information...

Something doesn't make sense. You have a manual damper?? Maybe it got misaligned and you think it's open when it's really closed.. a draft that strong should melt the stove. Your draft should run around .04 during normal operation..

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Post by franco b » Fri. Oct. 24, 2014 8:18 pm

I read your new info. A partially blocked chimney could have this effect. Good draft number but unable to handle any volume, just like an undersized chimney. You mentioned a reading with the door closed. Open it wide and see if the reading drops. Certainly is a puzzlement since you have experience with the stove. Check the chimney visually with a mirror at the bottom in daylight. And yes use the POST REPLY button just below the post.

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