Draft Adjustment Problems - Help Please

 
DJWFire
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Post by DJWFire » Sat. Nov. 01, 2008 6:20 pm

I just finished hooking up and firing a KA-6 Keystoker Hot Water Boiler.

Problem is, I installed the factory supplied automatic damper and can not get it adjusted far enough.

Keystokers instructions say -.02 at idle and -.01 when fired.

With the Automatic damper adjusted all the way it is still reading -.04

If I took the damper completely out or held it wide open the reading would go to -.01 while running, but when it went to idle we could smell the sulpher smell.

Thanks for your input!!


 
Complete Heat
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Post by Complete Heat » Sat. Nov. 01, 2008 6:35 pm

You do not want to go higher than a .04 draft because it can lead to a hopper fire. If it is reading .03 to .04 on a high fire, you should be OK. Try that and see what kind of results you have with that. If you still get a sulphur smell, it could be a poorly drafting chimney.

Mike

 
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gambler
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Post by gambler » Sat. Nov. 01, 2008 7:23 pm

DJWFire wrote:Keystokers instructions say -.02 at idle and -.01 when fired.
There is something wrong with those instructions.

You want -.04 when you are firing and have been for a while to make sure the chimney is hot. The -.02 at idle sounds good.

 
DJWFire
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Post by DJWFire » Sun. Nov. 02, 2008 12:45 am

I am not sure what the deal is, I was just trying to adjust it to the manufacturers specifictions.

Maybe they made a typo on the manual.

 
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Machinist
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Post by Machinist » Sun. Nov. 02, 2008 11:44 am

Assuming the instructions are correct, maybe a larger damper is needed. I have a 7" damper on my 6" vent system.

Field Controls has great info about draft control.
http://www.fieldcontrols.com/draftcontrol.php#dctop

 
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gaw
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Post by gaw » Sun. Nov. 02, 2008 5:05 pm

You adjust your damper weight for .02 draft. There is a scale on the damper, .02 is achieved by sliding the weight out (or up depending on how you view it) the ramp all the way. The damper may be wide open at times. If you have a good drafting chimney it may be half to full open much of the time. You confirm your draft setting by taking a reading with a draft gauge through the little hole drilled in the fire observation door. The fire should be well established and boiler water up to operating temperature, the stoker motor must NOT BE RUNNING. When you are satisfied with the draft setting adjust a thermostat to make the stoker run. Under the stoker fan shrouding is an air shutter. A screw secures it from moving. Loosen the screw to move the shutter and open the shutter to the point that you see a reduction in the draft reading taken through the fire door. Depending on the amount of draft your chimney pulls you may open this shutter all the way (strong draft) or have to close it almost shut (poor draft). Moving this air shutter is how they achieve the .01 draft when stoking, by introducing more air. Don't get too hung up on the numbers. If you can't drop the draft much or any by opening the air shutter so be it. You do want to keep the draft at about .02 during idle times. If your damper can't achieve this you may have to put a bigger one on.

 
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Post by Motorbike » Sun. Nov. 02, 2008 9:25 pm

Complete Heat wrote:You do not want to go higher than a .04 draft because it can lead to a hopper fire. If it is reading .03 to .04 on a high fire, you should be OK. Try that and see what kind of results you have with that. If you still get a sulphur smell, it could be a poorly drafting chimney.

Mike
(Not trying to be a wise guy)

If you have a draft of .04 or so, how is that a poorly drafting chimney?


 
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Freddy
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Post by Freddy » Mon. Nov. 03, 2008 6:03 am

Do you have a manomometer hooked up? The settings on a damper are just approximate.

Tell us about your chimney. Height, type, inside size? Is it inside or outside the building? If you are getting a sulpher smell either A: At some point you have negative draft or B: You do not have enough make up air coming into the room.

 
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Post by LsFarm » Mon. Nov. 03, 2008 10:51 am

Follow the directions from member gaw. They are right on the money.

Greg L

 
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Coalbrokdale
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Post by Coalbrokdale » Tue. Nov. 04, 2008 8:12 am

Guys I can't help but notice you numbers are Negative.....

Keystokers instructions say -.02 at idle and -.01 when fired.

With the Automatic damper adjusted all the way it is still reading -.04


That would be positive pressure in the stove and stack not good. Negative draft. The Manometer is reading vacuum not air pressure like a tire gauge. The concept is that the chimney is sucking air out of the stove and the Baro Damper is opening to lower the vacuum. I think it should be reading .02 at idle since the combution fan is not running and the natural draft is pulling air through the fire. when fired the fan is adding air to the fire box and increasing the pressure in the firebox and Stack to the point it is close to neutral but still a vacuume .01 not -.01 Chimneys suck.....

 
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Post by gambler » Tue. Nov. 04, 2008 9:27 am

Guys I can't help but notice you numbers are Negative....
They are supposed to be negative.
The manometer measures pressure differential. A negative pressure is a vacuum.
Most here hook the tube from the flue pipe to the positive side of the manometer so you can have a larger scale. So you are actually sucking on the positive side of the gauge.

 
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Post by WNY » Tue. Nov. 04, 2008 11:00 am

The stove should be under a slight vacuum all the time. The reading should be (-) Negative (If manometer is hooked up correctly). The Heat generated flows up the chimney and keeps it pulling thru the stove. If you have POSITIVE Pressure, you would be leaking out any air gaps in the stove and out the Baro and CO would leak into your house. (Not a good thing).

However, Depending on how you hook up your gauge or the reading on it, it might not have a (-) negative in front of the values. Some draft gauges may only read 0-1" Inches of water or something, but you must know it is reading a Vacuum (Negative pressure).

 
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Post by Machinist » Tue. Nov. 04, 2008 1:23 pm

I use a Bacharach MZF draft gauge. It has no + or - on it so I gently blew air into it to determine what direction the needle needs to move. Pressure on this gauge moves it's needle to left, so Vacuum (- draft) is to the right.

The same method can be used for manometers.

 
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Coalbrokdale
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Post by Coalbrokdale » Tue. Nov. 04, 2008 1:29 pm

Mine is setup A$$ backwards then. I understand the concept of atmospheric pressure and vacuum. I guess I can switch the hose so it read on the other side of the scale. I always assumed inches of water was measured on the positive side of the scale...meaning negaitive pressure.

 
DJWFire
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Post by DJWFire » Tue. Nov. 04, 2008 2:12 pm

Machinist wrote:Assuming the instructions are correct, maybe a larger damper is needed. I have a 7" damper on my 6" vent system.

Field Controls has great info about draft control.
http://www.fieldcontrols.com/draftcontrol.php#dctop
Now that you have commented on that, My KA-6 was special ordered for a 6" chimney even though the standard KA-6 has a 8" chimney.

This may be the reason a 6" damper will not adjust down low enough.

I have about 16-18 feet of 6" Metalbestos chimney and approximately 5 feet of 24 gauge black stove pipe in the basement connecting to the furnace.


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