#vacuum

Tech Tips:

Vacuum: Moisture vs. System Leak
By:Don GillisThis tech tip was written by Don Gillis with Chemours. Thanks, Don! Evacuation helps remove contaminants, like moisture and non-condensable gases, from HVAC/R systems, especially ones that are put into service for the first time or put back into service after a repair. Even though pulling a deep vacuum has always been a best […]
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Two Tips for Tough Vacuum Jobs
By:Matthew BrunerIn the last year or so, I have had a couple of puzzling experiences related to pulling a vacuum. These instances have left me with questions and clues where I thought I had given up on understanding a certain vacuum situation. Typically, if I’ve had a hard time achieving a proper vacuum, I would […]
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Scroll Compressor Pump Down, Megohm Test & Fusite Terminals
By:Bryan Orr This tip will be like an episode of Columbo; we will start with the what and who and then get to the why. Don't pump down a scroll into a vacuum. Don't run a scroll in a vacuum. Don't run a high voltage megohmmeter or Hi-pot test on a scroll (As a general […]
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What is a Micron?
By:Bryan Orr To answer the question in the title, we use it as a measurement of pressure. REALLY, it is a measurement of distance. First, any scale CAN be used to measure vacuum (negative pressure) and positive pressure. The trick is knowing which is best suited for which and the size of the scale. Larger […]
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Which Valve Do I Open First?
Testo 557 vacuum gauge and Appion core removal tools shown I've had a change of heart. Back in the early 2000s, during the big construction boom, I did many system startups on residential units for a large company I worked for. When installers ran the line sets prior to startup, they weren't always very careful […]
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Do You Need to Be Recovering Into a Vacuum?
By:Bryan Orr This topic came up because I was testing out the new MR45 digital recovery machine. That machine goes off by itself when it hits a 20″ Hg vacuum. It's a cool feature, but it is good to know when that level of vacuum is overkill and when it's not enough according to EPA […]
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Does Air or Nitrogen Absorb Water?
By:Bryan Orr There are many examples of teaching using metaphors to help someone grasp how something works without being EXACTLY correct. Some examples are how we often use water flow to explain electrical flow or refrigerant circuit dynamics. It's enough like the way it works to get our heads wrapped around it, but there are […]
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Can Pulling a Vacuum too Fast Freeze Water/Moisture?
First, I want to give credit where credit is due. This post is made possible by the fantastic demonstration video by Neil Comparetto that I embedded below. Before you get bored and stop reading, I want to get the conclusion out in the air. Ice can form in a vacuum, but I still advise pulling a […]
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Testing the Leak Rate on Your Micron Gauge Itself
As a technician gains skill, they will learn that regularly testing your tools is a huge part of success. It isn't long in the field before techs find out that just because a meter or gauge gives a particular reading, it doesn't ALWAYS mean it is correct. Vacuum is one of these areas. Everything in […]
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Videos:

How to Evacuate an AC system, Full Vacuum Procedure
In this first video Bryan goes deep into how to evacuate or “vacuum” an air conditioner in a video collaboration with Paul from The Engineering Mindset channel. We also wrote an article on evacuation for the ACHR NEWS that you can find HERE Article on proper micron gauge placement HERE Can you freeze water in […]
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Testing the Leak Rate on Your Micron Gauge Itself
As a technician gains skill they will learn that regularly testing your tools is a huge part of success. It isn't long in the field before techs find out that just because a meter or gauge gives a particular reading it doesn't ALWAYS mean it is correct. Vacuum is one of these areas. Everything in an […]
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What if you Only Have One Large Hose?
When evacuating, the FASTEST way is to use two large diameter hoses connected to two core removal tools and the cores removed. These hoses are then connected to the pump using a tee or evacuation “tree”. However, when you only have one large hose another acceptable method is to connect the large hose to the suction […]
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Podcasts:

Vacuum and Recovery in an A2L World with Jesse Stewart
By:Bryan Orr  In this podcast, Bryan Orr interviews Jesse Stewart from NAVAC about A2L refrigerants and compatible tools and safety procedures. They discuss how NAVAC has a full line of A2L-compatible tools for evacuation and recovery, including the new NR7 and upgraded models of the NRDDF and NRDD. Jesse explains key features that make […]
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Evacuation 101 w/ Jim Bergmann (Podcast)
By:Jim BergmannBryan Orr In this episode of the podcast, Jim reviews the basics of evacuation and dehydration. He also covers hoses and vacuum gauge placement. Evacuation may just seem like a method to suck air and water out of a system. However, it is an intricate science that lacks a lot of detail in most […]
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Solder Rings, Thermal Imaging, and My Grouchy Brother
By:Bryan OrrNathan Orr In this episode of HVAC School, I talk with my brother Nathan… and he whines a lot about cool tools I like. As you might have guessed, Nathan is in the camp of people who believe that proper training promotes good practices; fancy tools won't make an outstanding tech. Even though I […]
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