This Is Why You Should Always Measure Your Draft

Matthaus · Post by **Matthaus** » Mon. Jan. 15, 2007 4:31 pm

Look Closely at these two pics, compare the manometer reading to the opening of the barometric damper (and weight location).

It was an eye opener for me!

coal_kid · Post by **coal_kid** » Mon. Jan. 15, 2007 10:11 pm

I found I had bad seal on my feed door on my burner. I was pulling -0.03 normally, if I’d push the door closed I was going up to -0.07. I’m running my damper closed alot more, and have a much more efficient fire, just as you are.

Post by **coaledsweat** » Tue. Jan. 16, 2007 11:10 am

Matthaus
Now take some aluminum foil and completly block the barometric damper with it and see what it reads. Should be interesting.

That's why you always run a baro.

wenchris · Post by **wenchris** » Tue. Jan. 16, 2007 1:25 pm

Question, does the draft stay constent once set? Does fire size, outside temps play a role. I was under the impression that once it is set it stays there. I'm beginning to rethink that thou

Stay warm, Jimmy

Post by **coaledsweat** » Tue. Jan. 16, 2007 1:39 pm

Like you thought, it doesn't remain constant for a variety of factors like the ones you mention. But it shouldn't vary a lot. You need enough draft to maintain the fire and the baro will break it if it starts to get to high. If it gets way up there you risk overfiring the unit and could damage it or an even worse scenario.

Matthaus · Post by **Matthaus** » Tue. Jan. 16, 2007 11:37 pm

Am in Texas right now, when I get back will continue the science project!

I do know that with the coal-trol managing the speed of the combustion blower/stoker in the triburner unit that the static pressure of the stove goes up at high fire rates. This results in about a .02 less draft at max fire, never goes below .03" to .04" WC though.

Good thing about the coal-trol is that max fire is controlled so no worries.

wenchris · Post by **wenchris** » Wed. Jan. 17, 2007 1:21 pm

Picked up a Dwyer Mark II Manometer today, Graingers $31.86 with my friends account. My Harman mag should be set between .04 and .06 I can only get .03

The manual say's to do this on "pilot mode" is this with the combustion fan on or off??? Also states: "with the stove burning and stabilized set barometric damper at .04 to .06. To get the .03 the baro is closed and combustion blower restrictor plate is also closed. This in turn will give me very high stack temps. Maybe the chimney is not high enough. Been my second season with it and was just trying to maybe improve on something that is not broke. Made my own leveling stand out of scrap I have laying around, could not see paying $26 for their stand. Ant suggestions.... Stay warm Jimmy

Post by **coaledsweat** » Wed. Jan. 17, 2007 1:33 pm

When the blower runs you may even get a positive draft #, it is irrelevent. The reading you want is when the blower has been off and the unit is using a natural draft. A stoker doesn't need a lot, .03 should be enough for a low fire and it should increase your draft as you ramp up the fire. Normally you need about 15' for a chimney, but details can change that.

Matthaus · Post by **Matthaus** » Wed. Jan. 17, 2007 10:55 pm

Hey Jimmy, you didn't mention where you have the baro damper weight set.

Set it on .08 and then take a reading. Just a thought, may be off base.

jpen1 · Post by **jpen1** » Thu. Jan. 18, 2007 12:25 am

Jimmy,

I remember reading an older post in which you had problems with CO and fumes on a low fire or at leat I think so. It is hard to tell from those pictures but it looks like your chimney isn't high enough. Your chimney should be at least 2' higher than any roof peaks on your house or that atleast is what the old timers have always told me. My baro is set at .05 and even on a low fire with temps in the 60's outside my damper is at least part way open. Today I once noticed that the damper was wide open when the unit was at the high fire setting. Does your damper open up with it set at .04 or is it stagnet? Is the chimney higher than the highest roof peak?

wenchris · Post by **wenchris** » Thu. Jan. 18, 2007 10:13 am

The chimney is about 2 ft lower than the top of the peak. The problem I had with the CO was a large piece of coal stopped the pusher block and the fire was burning back towards the hopper. The stove burns great and I'm getting plenty of heat. Was just trying to improve it. I can get .03 on the manometer but the baro is all the way closed and so is the restrictor plate on the combustion plate. This gives me stack temps that are way to high taking the heat up the chimney. I guess better is the enemy of good.
Stay warm, Jimmy

Post by **coaledsweat** » Thu. Jan. 18, 2007 10:30 am

I think the chimney top is supposed to be 2' higher than the roof measured 5' from chimney in your case. It looks fine, but for some reason it looks taller today than it did yesterday.

Post by **coaledsweat** » Sat. Jan. 20, 2007 5:11 pm

coaledsweat wrote:I think the chimney top is supposed to be 2' higher than the roof measured 5' from chimney in your case. It looks fine, but for some reason it looks taller today than it did yesterday.

That's wrong it's within 10', not 5'.

Anyway I just noticed my barometric doing it's dance as it's very windy and cold today. So out of curiosity I took some tinfoil and capped it off. Pow! shot right up to .08 and hung close to that, it normally breaks around .055, .06 max. And I don't have a great chimney, just think what a good one would do.

barley master · Post by **barley master** » Tue. Jan. 23, 2007 9:41 pm

i see that you have a chimney cap. also how many ellbows do you have? I had a chimney cap some years ago with two 90*ellbows and could never hit an .05 except on windy days. since then I was able to eliminate one 90 with a 45 and the chimney cap rotted off, since then I have no problems of getting and maintaining .05 on a calm day.

This Is Why You Should Always Measure Your Draft

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