I have recently switched to using a Minneapolis Duct Blaster and have noticed that switching the rings has been resulting in varying results. My question is which reading is more accurate? I know…Continue
"Sorry for chiming in so late. Sean’s comment early on in the discussion was the closest to the point. 160 CFM is off the calibration charts on the high end. Your Duct Blaster® Ring 3 may be able to top out at 160 CFM with…"
"Michael, how do you know the tester would not start out with Ring 3, take a reading and assume it was ok?
What this repeated test is pointing to is that there is a problem here, so what is it? Is Ring 3 out of calibration for some reason, was the…"
"If your getting a good reading with the 2 ring on, using a DG 700 and it is not flashing LOW then that is the proper flow range. Sure you could put on a 3 ring and get a different number but why? The 2 ring matches the flow range. The 3 ring has a…"
I suggest checking your gauge and Duct Blaster on a regular basis with this simple set up. You’ll learn a lot and have fun too. The Principle is, if what you are blowing into, a duct or flex with a hole in it, is at the same pressure…"
I have recently switched to using a Minneapolis Duct Blaster and have noticed that switching the rings has been resulting in varying results. My question is which reading is more accurate? I know that each ring is used depending on the amount of leakage in the duct system, however it doesn’t seem clear which ring I should be using. Yesterday I test a 1.5 ton system in a condo and I used the #2 ring. I got a result of 240 CFM then I put in the #3 ring (smallest one) and got 180 CFM. Which one is…See More
A good rule of thumb when you get readings that stretch credibility - or just don't make sense - Break down your (DG) set-up and redo it. That will often make a glitch , like not switching the gauge to match the ring, stand…"
"Thats why I was confused on my readings because I'm still getting a reading outside of what the CFM should be for that ring. If it is out of range does that mean its wrong?
I did a field calibration and I'm slightly higher than the CFM of…"
"It may not be the Blaster but the water vapor presser inside, air speed outside. I have also found duct leaks change with attic temp. I have found return air leaks if in a stud of wall change with Relativity Humidity in wood and sheet…"
"You were testing leakage to the outside and total leakage, and also doing a Blower Door Test on the condo?
If so, what surfaces were your sealed vents on. Drywall? Laminate/tile Flooring? Carpet? How did you seal those?…"
"Just checking all the bases. Did you remember to switch configurations on the dg 700 to account for the different rings? That would certainly make a difference.
I built a test box- 2 ft square where the duct blaster attaches to…"
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