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manometer accuracy


paulmars's Avatar
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Join Date: Oct 2008
Posts: 123
FL

02-12-18, 09:20 PM   #1 (permalink)  
manometer accuracy

What is a good reasonable priced accurate manometer to measure my barometric damper?

My furnace should be 0.025 and my flue should be -0.02. Looking at the gauges for sale i see accuracy (read
inaccuracy) ratings that would make readings in the range that I need almost useless. Exp:

0.3% of full scale 55.00wc (0.003x55=0.165) Does that mean that a reading of 0.02 could be off by as much as 0.165?

+/-0.3% of full scale 83.02 InH2O NKTECH NK-L3 (0.003x83.02=0.249)

1.5% of full scale 4.00wc Dwyer 478A-0 (0.15x4=0.6)

Am I doing something wrong here?


tks,
pa

 
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Pilot Dane's Avatar
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NC

02-13-18, 07:14 AM   #2 (permalink)  
I would look for a instrument that is more appropriate for the pressure you're trying to read. A gauge capable of reading up to 55" WC is way too high for your very low pressure application. It's like using a 3'000 psi gauge to check the 30 psi in your car's tires. There are gauges that max out at .5 so any inaccuracy would be very minimal. Dwyer makes some simple plastic gauges that are quite inexpensive and has the scale expanded at the low end for increased accuracy and probably would be perfect for what you're doing.


 
paulmars's Avatar
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02-13-18, 07:37 AM   #3 (permalink)  
none that Ive found. that dwyer shown +/-3.0 of 3.0 is 0.09, so a reading of 0.02 could be anywhere from 0.11 to -0.07

 
Pilot Dane's Avatar
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02-13-18, 09:25 AM   #4 (permalink)  
I would not over think it. A liquid in tube meter is about as accurate as you can get without spending a lot of money. Much of the accuracy will come from how level you install the gauge and set the zero.

 
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