Pitot Tube?

 
dll
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Post by dll » Tue. Jan. 24, 2012 3:59 pm

A pitot tube is used for calculating high velocity air movement in ductwork and as mentioned above it's used mostly on aircraft.

The lowest reading you could take with any accuracy from a manometer with a pitot tube is around .01 inches of water. This would calculate out to a face velocity of 401 ft/min. Even at that reading your error is somewhere around +/- 30%.
If you get a reading of .02 inches the face velocity is 566 ft/min and the accuracy of that reading is +/- 15%.
Also you should be taking readings at 6 or 12 points across the diameter of the duct.

 
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SMITTY
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Post by SMITTY » Tue. Jan. 24, 2012 8:46 pm

jpete wrote:What happens if I hook everything up and the gage barely moves?

I follow the instructions by backing out the zero adjust knob and then turned it in 3 turns before I filled it with oil.

I plugged into the low side and it moves up one line.

Granted, it's mid 50's right now so I would expect it to be low, but not zero.
Mine was at .025" this morning with the fire dying down. Got up to 50° today. It's cranking now & not even drawing .04" . On single digit nights it pulls a steady .06" with the boiler baro flapping.

It's gonna take a while to get that whole chimney warmed up, which will then increase the draft a bit. My chimney has never been cleaned in the 9 years I've been here ... and who knows if it was prior.


 
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jpete
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Post by jpete » Tue. Jan. 24, 2012 9:02 pm

Looks like I'm running at .02" just idling right now.

I have to say, this manometer thing is a bit anti climactic. :)

 
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Poconoeagle
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Post by Poconoeagle » Tue. Jan. 24, 2012 11:36 pm

the first wicked hard gust sucks the red oil way up there and if you look at the fire it really roars....

then when you open the baro all the way and it drops you smile.....thus the delayed climax
after the first big ....

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