Draft on the Lower or Stronger Side.

I have been burning coal now for 3 years and this question might seem like a dumb one. I would like to know peoples thoughts if its better to have a draft on the lower or stronger side. I know the stronger the draft the more heat goes up the chiminey but will it burn up the coal any better. I have a keystoker koaker and this is the first year that I am burning buckwheat with no problems. I use a manometer to set the draft the way keystoker recommends 2 on the manometer on a full burn. keystoker recommends 2-3 I believe. Thanks for your advice..

Rich

Rich9876 wrote:I have been burning coal now for 3 years and this question might seem like a dumb one. I would like to know peoples thoughts if its better to have a draft on the lower or stronger side. I know the stronger the draft the more heat goes up the chiminey but will it burn up the coal any better. I have a keystoker koaker and this is the first year that I am burning buckwheat with no problems. I use a manometer to set the draft the way keystoker recommends 2 on the manometer on a full burn. keystoker recommends 2-3 I believe. Thanks for your advice..

Rich

From what I've seen they say to set the draft to manufacturer's specs with a manometer when the stove is at peak out put or on high heat. With mine it's .06 to .08 so that doesn't leave too much to fool with.

Yes I know that there isn't much room but my question was does the coal burn better and produce more heat at a stronger draft at full burn I get good draft but at idle I get little to no draft. Wouldn't it be better to have a bit more draft at full burn and more at idle then to have less?

answer to question is its always preferable to have a strong drafting chimney (many ways to tame it, not many ways to increase draft if its not their its a lot of work). having said that... the desired draft through your coal varies by stove, varies according to YOUR needs, varies by temps. for the most part handfired coal stoves suggest a .04 draft but its really up to YOU to learn your stove, house and heat and play with it from their.... here is a sample thread of playing with it...Chimney Draft Failure

I always have my draft set on the lower side. I just checked keystoker's website and they say .02 to .04. I seem to have mine just above .02 on a full burn.

There are some mfg'r that call for their stove's draft to be read over the fire...as opposed to at the breech

The 2 different locations are not the same reading, so be sure where your mfg'r reading is to be taken.

You want to have your draft set based on Keystoker's specs. This will run your stove most efficiently and SAFELY!! Minute changes in draft aren't going to change your burn characteristics, but it will suck more heat our of your stove thus wasting it (if the draft is too high). All your combustion air comes from your combustion blower and that is what controls your burn characteristics. If your draft is so high that it is sucking more air through your coal bed than what your fan is blowing (thus getting a hotter fire), then you are probably guaranteed a hopper fire. If you draft is too low (theoretically keeping more heat in your stove), you will risk CO leaking into your house out the stove. Neither of these circumstances are worth risking just to save a little heat.

If you want a hotter fire, open the shutter on the combustion fan more to let more air blow through coal bed. BUT, watch your manometer and make sure your draft keeps up with the increased air input. If it can't than the fire box will pressurize and leak CO out the door gaskets.

Like the previous poster mentioned, set your draft to recommended number on full burn (and low to no wind also helps). With mine properly set, my draft usually drops down to .02 (kokers are recommended at .025) during low to normal burn. I usually don't need a full grate of coal burning to maintain my house temps. So, in my case, if I was to purposely set my initial draft low to save heat, then I would probably have CO issues when my fire wasn't burning fully because my actual draft would be too low on partial burns.

Also, as per McGiever, make sure you are testing you draft ("over the fire") next to the ash pan door. A lot of stoves need their drafts checked at their exhaust tube termination, Keystoker has a hole next to the ash pan door specifically for draft measurement.

Rich9876 wrote:I always have my draft set on the lower side. I just checked keystoker's website and they say .02 to .04. I seem to have mine just above .02 on a full burn.

Just so no one gets misinformed. I just checked the online koker manual and they suggest between .02 to .03, not .04. So if you are just above .02 then you right on the money. I think my original koker manual (before they updated them a year or so ago) stated a .025 target, which is probably where you draft is sitting.

Thanks WNY I was just about to reword the question. My whole issue with the draft is that when the stove is at idle my reading on the manometer is less then .01 sometimes it doesn't even register. That's when I have a reading just above .02 at full burn. Also if you check the koker manual again earlier it says .02-.03 but later it says after a fire has been going for a while it should be between .02-.04 this is the koker direct vent manual. (Which I assume is power draft if so I don't have this one).

koker with thermostat manual
CHECK DRAFT- After starting a fire and a good fire is established, the chimney will be warm enough to check draft. The draft range should not go lower than -.02, nor above -.03. The air shutter on combustion motor and/or the barometric damper on stove pipe may be used to obtain proper draft readings.
If draft goes above -.03 adjust barometric damper to open a little wider.
If draft goes below -.02 close air shutter on combustion motor.

koker direct vent with thermostat manual

CHECK DRAFT- After starting a fire and a good fire is established, the chimney will be warm enough to check draft. Insert draft gauge into predrilled hole, located in the
side of the ash door frame. The draft range should not go lower than -.02, nor above -.03. The air shutter on combustion motor and/or the barometric damper on stove pipe may be used to obtain proper draft readings.
If draft goes above -.03 adjust barometric damper to open a little wider.
If draft goes below -.02 close air shutter on combustion motor.
When stoker unit is running to satisfy thermostat, you should have a full grate of fire, except for the bottom 2” of grate. The lower part of the grate should have ash covering it.
When thermostat is satisfied, the gear motor will not run continuously, gear motor will only run intermittently. During the time when thermostat does not call for heat, the
timer will turn feed motor on to maintain a small fire approximately 2” in length. Settings of timer may be adjusted.
To increase size of fire bed or to reduce coal feed, adjust white nut (coal feed adjustment nut). To start another fire, it is not necessary to adjust coal feed. Some smoke may be visible when starting a fresh fire, but should not persist.
After a fire has been established and the stove is warmed up, a draft reading should now be taken. Use pre-drilled hole on side of ash door frame and insert draft gauge. Draft gauge should read between -.02 to -.04. The combustion air shutter is preset at factory.
If any further adjustment is needed to obtain proper draft reading . . . slide adjusting rod (located in rear of venter) in or out to obtain proper draft. Secure adjustment rod with set screw.

Last night I increased my draft while it was at idle to .01 solid and today with a full burn I increased it a little more now I am closer to .03 for my full burn draft taken by the ash door port. I just don't want to have a hopper fire or CO issues. I have good digital CO detectors thru out the house. (4 of them)

Again Thank you WNY and thanks to everyone else

You really shouldn't have to fool with your draft once you get it initially set. I am assuming you are manipulating your barometric damper to change your draft?? Once you have your damper weight set based on a full burn and manometer reading, it usually doesn't need to be changed. If you originally had your draft set properly and had low draft readings (you mentioned .01), you probably just needed to close your combustion fan shutter a little so you weren't forcing more air into your firebox than what your draft could handle. Once it gets consistently colder, you can probably open your shutter more since you chimney should draft better.

I haven't really messed with the barometric damper mostly the combustion fan shutter. Just concerned with the low readings at idle. Today I've been tweaking it at a full burn and have the draft set closer to .03. Today is the only time I adjusted both the barometric damper and the combustion fan. I made it a little heaver on the barometric damper and then tweaking with the combustion fan.

Always remember...when adjusting the combustion fan air, as the number approaches zero your stove approaches going POSITIVE and then Carbonmonoxide (CO) will spill out into the room.
CO Detectors must be in use always.