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Manometer readings too low???

Posted: Mon. Mar. 12, 2018 9:02 pm
by rookiecoalburner2
This is my first winter burning coal with a Harman Magnum stoker stove and I bought a dryer model 25 manometer from other threads that I've seen on this website and I'm wondering if my chimney draw is enough it fluctuates between .03 to.05 on the gauge which I guess would be .03 to .05 inches of water column vacuum. Should I have more draw on the stove and chimney than that or not I've seen threads were guys have had really strong chimney drafter draw and it actually sucks the heat out of the stove I'm getting good heat out of the stove and things seem to be working well should I just let it alone

From the top of the stove is 6 inch black pipe into 8 in thimble throgh wall to a 6 inch by 12 inch chimney flue that is approximately 25 feet high

Should I ask 6 inch the whole way to the top of the chimney

Re: Manometer readings too low???

Posted: Mon. Mar. 12, 2018 9:05 pm
by freetown fred
You got it with that last ditty--Orrrrrr, ya could complicate the hell out of it!! .>)

Re: Manometer readings too low???

Posted: Mon. Mar. 12, 2018 9:31 pm
by michaelanthony
If I read this right, you have a 8" to 6" reducer on the stove pipe from the stove? You can use 6" all the way to the chimney and use fiberglass insulation around the pipe in the thu-wall...just a thought.

...sounds like your chimney is tall enough without any obstructions.

Re: Manometer readings too low???

Posted: Mon. Mar. 12, 2018 9:32 pm
by Lightning
rookiecoalburner2 wrote:
Mon. Mar. 12, 2018 9:02 pm
I'm wondering if my chimney draw is enough it fluctuates between .03 to.05
Well, firstly what port on the Dwyer did you connect the mano probe to? And where are you taking the reading? Then on the manometer itself, which side of zero are you reading?

Re: Manometer readings too low???

Posted: Tue. Mar. 13, 2018 7:52 am
by rookiecoalburner2
lightning,i have the hose that came with manometer plugged into the "low" side port with a piece of brake line in other end at stove. nothing on high side port.im checking draw between the stove and the barometric dampener like owners manual says.the .03 to .05 readings are on the right hand side of "0". in the black not red..

Re: Manometer readings too low???

Posted: Tue. Mar. 13, 2018 8:06 am
by freetown fred
Check PM's--top right corner----

Re: Manometer readings too low???

Posted: Tue. Mar. 13, 2018 8:14 am
by Rob R.
That should be fine. What is most important is the draft in the firebox. Does your stove have a draft port on the front or the fire door?

Re: Manometer readings too low???

Posted: Tue. Mar. 13, 2018 8:23 am
by windyhill4.2
.03-.05 is good.... unless you think your baro needs to work harder.. :)
Seems as tho your baro is doing a superb job keeping the draft in the optimum range. :yes:

Re: Manometer readings too low???

Posted: Tue. Mar. 13, 2018 8:49 am
by freetown fred
If you feel compelled to do something, I would go with MA's suggestion with running straight 6" pipe to & through thimble & pack with fiberglass with deco ring, not that I think it would make any difference. :) Do NOT even think about a liner for the actual chimney!!!!!!!!!!!!!!!!!!!!!!

Re: Manometer readings too low???

Posted: Tue. Mar. 13, 2018 9:24 am
by windyhill4.2
rookiecoalburner2 wrote:
Mon. Mar. 12, 2018 9:02 pm


From the top of the stove is 6 inch black pipe into 8 in thimble throgh wall to a 6 inch by 12 inch chimney flue that is approximately 25 feet high
I seem to be reading this differently than some others have. :?
Explanation...
I read that he has 6" pipe from the stove to the thimble, the thimble is 8",so a reducer is used at the thimble. :annoyed:

Well, at least that is the way i read what i saw the OP post. :)

Re: Manometer readings too low???

Posted: Tue. Mar. 13, 2018 9:27 am
by Lightning
rookiecoalburner2 wrote:
Tue. Mar. 13, 2018 7:52 am
lightning,i have the hose that came with manometer plugged into the "low" side port with a piece of brake line in other end at stove. nothing on high side port.im checking draw between the stove and the barometric dampener like owners manual says.the .03 to .05 readings are on the right hand side of "0". in the black not red..
Perfect ;)

Rob R. wrote:
Tue. Mar. 13, 2018 8:14 am
That should be fine. What is most important is the draft in the firebox. Does your stove have a draft port on the front or the fire door?
:yes:

Re: Manometer readings too low???

Posted: Tue. Mar. 13, 2018 10:19 am
by rookiecoalburner2
Rob..i have matched the draw reading of chimney to the draw of firebox by adjusting combustion motor restrictor plate..
While stove is off pilot mode and making heat.manometer reading is at .05..heat coming out of pipe routed from stove in badement to register in living area,air temp is over 120 deg..pins a outdoor type thermometer

Re: Manometer readings too low???

Posted: Tue. Mar. 13, 2018 10:27 am
by titleist1
I would consider the chimney draft you have to be in the sweet spot.

The port Rob is asking about is between the firebox door and the ash pan door.
There is an allen head bolt there that can be removed with some persuasion.....maybe!
You just need to use the manometer via that port to make sure the firebox isn't pressurized due to the combustion fan cover being open too far. As a first guess the cover should NOT be more than 1/2 open and probably not less than 1/3 open. Use the firebox reading on the manometer versus what you know the chimney reading is to dial in the position of the combustion fan cover.

Re: Manometer readings too low???

Posted: Tue. Mar. 13, 2018 8:53 pm
by rookiecoalburner2
Titleist1,thats exactly what ive done.restictor plate is abot 1/2 open..used port with allen head bolt to take firebox draw..

Re: Manometer readings too low???

Posted: Tue. Mar. 13, 2018 8:54 pm
by rookiecoalburner2
rookiecoalburner2 wrote:
Tue. Mar. 13, 2018 8:53 pm
Titleist1,thats exactly what ive done.restictor plate is abot 1/2 open..used port with allen head bolt to take firebox draw reading