Dwyer Mark II Manometer
- tcalo
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I just purchased a Dwyer II Model 25 manometer. I've read through so many manometer posts that my eyes started to bug out... . I want to be sure I hook this unit up correctly. It will be permanently hooked up to my hand fed stove. My configuration is stove, MPD then Baro. Straight flue out the roof. About 6' of single wall black pipe from the stove to the ceiling. Then about 12' of double wall SS through the attic and out the roof. I have some questions:
- Where should the brass fitting for the manometer be hooked up into the flue, between the MPD and Baro?
- Should the brass fitting go straight into the flue or angled either down or up?
Would I be able to install the manometer before the MPD if needed?
Thank you
- Where should the brass fitting for the manometer be hooked up into the flue, between the MPD and Baro?
- Should the brass fitting go straight into the flue or angled either down or up?
Would I be able to install the manometer before the MPD if needed?
Thank you
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I would put it just below the manual pipe damper. You want it to read what the stove feels.
It might be a little hot there for a rubber connector to the brass fitting, but if the stack does not exceed 300 it should be OK. Small pilot hole and then 3/8 drill and and then screw straight in with the brass fitting. Push on 6 inches of rubber and the the plastic tube goes inside that.
It might be a little hot there for a rubber connector to the brass fitting, but if the stack does not exceed 300 it should be OK. Small pilot hole and then 3/8 drill and and then screw straight in with the brass fitting. Push on 6 inches of rubber and the the plastic tube goes inside that.
- Lightning
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I used a section of steel brake line to get the rubber hose away from the pipe about 12 inches. Like Franco pointed out, you need to get the reading between the stove and MPD. It's most beneficial to know what the negative pressure in the stove is.
- tcalo
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I plan on using 1/4" copper out of the flue. It's a bit bugger than the plastic tubing that comes with the gauge, would the size difference affect the reading?
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You can seal it with some hi temp. silicone.tcalo wrote:I plan on using 1/4" copper out of the flue. It's a bit bugger than the plastic tubing that comes with the gauge, would the size difference affect the reading?
- tcalo
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Sorry, I might not of been clear. I have 1/4" copper out of the flue reducing to the plastic tubing (not sure of the size). Would the reduction cause a false reading?
- Lightning
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No. I don't believe the bigger copper tubing would have an impact on accuracy. But like Franco pointed out, sealing it well is a must to make it accurate.tcalo wrote:I plan on using 1/4" copper out of the flue. It's a bit bugger than the plastic tubing that comes with the gauge, would the size difference affect the reading?
- joeq
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I used copper tubing also, (with a brass fitting...wasn't about to use the plastic one supplied in the kit.) I also have 2 provisions of hook up.1 before the MPD, and 1 after. In this pic, it was mistakenly hooked "after" the MPD, but was instructed by the members to use it "B4" the damper. It has since been replaced, and works well there.
- tcalo
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Got everything hooked up, working great. Thanks for the advice! I did overfill it a bit, used a plastic syringe to suck out the extra oil. Pics to follow. Stove is idling ~275 and pulling -.03. It's a piece of mind knowing what my draft is. Better safe then sorry! Trying to push through these warm days, seeing how low I can push my stove on an idle and maintain draft. Another question I've been pondering, would the length of line from the flue to the manometer affect the draft reading...just curious?
- Lightning
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I'm gonna go ahead and say no... Length shouldn't impact accuracy any, at least not with the length supplied with the unit.tcalo wrote:would the length of line from the flue to the manometer affect the draft reading
Another thing most of us do with the Dwyer is hook them up "backwards" so that the negative value is read on the positive side of the scale. You probably ran across that in your research. Its not important, just a matter of preference..
In the pic, the reading actually represents a negative .035"wc. The reason is that the positive side of the scale goes higher than you'll ever need to read while the negative side only goes to a -.05.
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- joeq
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If we ever witnessed a chimney fire, maybe the higher scale reading would be beneficial.Lightning wrote: The reason is that the positive side of the scale goes higher than you'll ever need to read while the negative side only goes to a -.05.
- Lightning
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Yeah, I've seen wind gusts push it up to a -.08 which would be off the scale the other way.joeq wrote:If we ever witnessed a chimney fire, maybe the higher scale reading would be beneficial.Lightning wrote: The reason is that the positive side of the scale goes higher than you'll ever need to read while the negative side only goes to a -.05.