Manometer Part II

[jdonna]

Hey guys, thanks for the direction on the dwyer markII. A few questions...

I installed it and made my own probe out of a piece of brake line to slip inside the flue thermometer collar.

I measured it off the high side of the meter because you have a bigger range. Are you guys using both lines or just one.

At cold flue temps with no fire and outside air temp of 45 degrees I am seeing .01, left the stove door open and shut it again after it had some warm air up it, it went to .02.

After starting a top down fire it went right away to .05 and then fifteen minutes with a wide open fire it was up to .09

Will post more with secondary combusting and some pics.

Is this a normal reading. 16 feet of 6" stainless liner in a center brick chimney and no insulation, flue cap and all.

Thanks guys!

 

[laynes69]

You won't have any issues with draft. I'm not sure about all manufacturers, but some that manufacturer furnaces specify draft. Our furnace requires a .04" for a low draft to a .06" for a high draft. Anything over that and the unit could overfire. For us, a barometric damper is required to keep the draft in line. With it only being 45 and you getting readings that high, you will more than likely see an overdraft. Of course the more heat you feed into the flue the greater your draft. Once a good fire is dampered down and burning well your draft should lower some. I only use 1 tube on the manometer, and its calibrated to zero when disconnected.

 

[jdonna]

With the secondary combustion going, I am measuring .10 with the primary air backed off to barely open. Hard to understand I could have such a strong draft with 16 feet of liner. The total chimney height is about 30 feet, but the liner terminates on the main floor and is capped on top. I did not insulate the liner either because only 3 feet of brick is exposed. Would the readings be higher if this stove had an internal leak somewhere I have been through completely once before last season?

 

[Battenkiller]

Is this a normal reading. 16 feet of 6" stainless liner in a center brick chimney and no insulation, flue cap and all.

Yes, that seems perfectly normal to me. What it is showing is what would be expected with about a 250ºF average flue gas temp over the entire 16' height. That's pretty normal for a wood stove and equates to about a 350-400º temp on a single-wall pipe about 20" or so above the collar. Is that the temp you were seeing on the pipe when you got the .09 reading?

 

[Battenkiller]

The total chimney height is about 30 feet, but the liner terminates on the main floor and is capped on top.

I'm confused. You say that the total height is 30' and not 16'? Is that correct? The liner goes up 16' inside the main flue and then there is a 14' section of unlined flue above that, and there is a cap on top of that? If so, you still have a 30' chimney and you should be getting a reading of .10 inches when the average gas temp difference is only about 150º or so.

 

[jdonna]

The total chimney height is about 30 feet, but the liner terminates on the main floor and is capped on top.

I'm confused. You say that the total height is 30' and not 16'? Is that correct? The liner goes up 16' inside the main flue and then there is a 14' section of unlined flue above that, and there is a cap on top of that? If so, you still have a 30' chimney and you should be getting a reading of .10 inches when the average gas temp difference is only about 150º or so.

First off, thanks for your help guys. Sorry for the confusion as well. There is 14 feet of chimney below it with no liner installed, used to have a basement woodburner and relined the upper part of the chimney with a liner and capped the top.

The oustide wall temp 20 inches up is roughly 400 degrees, and about 800 degrees on the internal probe. This oakwood runs all over the place depending on the stage of the burn. .10 on the manometer when its around 800 degrees on the internal probe.

Trying to diagnose this stove because on a cold day and a good coal bed with a half full load of good dry wood it will over fire the heck out of this stove.

At the end of the day I am trying to diagnose my setup before I think about buying a woodstock fireview.