Magnehelic Question

jrn8265 · Post by **jrn8265** » Mon. Aug. 24, 2009 8:12 am

I only switched because of the cheap find on Ebay and the magnehelic allows me to set it and forget it so my wife can see the draft without worrying about her needing to reset and remove hoses each time.

Yanche · Post by **Yanche** » Mon. Aug. 24, 2009 10:13 am

jrn8265 wrote:I had a dwyer II manometer that was .03% accurate to scale. The Magnehelic says .02% accurate to scale.

True, but a Magnehelic is much more expensive. I qualified my opinion with "the same dollar spent". Also at the draft values we are normally measuring the 2% accuracy degrades to 3 or 4% depending on Magnehelic model. You should also realize the accuracy is + or - of the full scale value not the actual reading value. That's why it's important to match the instruments full scale range to the value you are trying to measure.

jrn8265 · Post by **jrn8265** » Mon. Aug. 24, 2009 12:39 pm

Yanche, yep!

I have the 0 to .25 Dwyer which should be at 2% and stay there for the whole range.

This will work better for my application.

Could not pass up $25 as my manometer cost me $45.