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Hey Ed, Is It Possible to Hold a 500-Micron Vacuum on a Line Set if There Is Moisture in the System?


In this edition of "Hey Ed," Ed discusses if it is possible to hold a 500-Micron vacuum on a line set if there is moisture in the system.

Hey Ed, is it possible to hold a 500-micron vacuum on a line set if there is moisture in the system? That is a very interesting question, and I could answer it either way depending on my mood at any given time. If there's moisture in the system, we're gonna have to quantify the moisture. If there's a very, very tiny amount of moisture, yeah, we could probably hold a 500-micron vacuum, but if we have bulk moisture, we haven't achieved that deep vacuum that we desire, then no, it's not going to. Ultimately, what we can do is valve off the pump and do what they call a decay test, and we can look for the rate of rise. We're gonna see how much that vacuum rises in a short period of time, and there’s again a lot of bulb parking that can be done with that. I’m a big fan of a couple manufacturers that have apps and within a second or two, can measure the rate of rise. I like technology to do my measurements, if possible, but if I’m gonna throw some actual numbers at it, if I don't get a system down to 500 microns and it doesn't rise above 1000 microns in five minutes, I'm gonna call it to go. Again, always go back to looking at the app for guidance but get it down to 500. As long as it’s not going above that thousand number in five minutes, we’re good to go. And that’s the way I see it.

In this edition of “Hey Ed”, Ed discusses if it is possible to hold a 500-Micron vacuum on a line set if there is moisture in the system

Ed Janowiak is the Manager of HVAC Design Education at ACCA.


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Posted In: Hey Ed, Technical Tips

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