Glide at Static Pressure
Source: Refrigerant Slider in the Ref Tools App We've been pretty spoiled in residential and light commercial HVAC in the USA because we haven't needed to deal with glide much. In HVAC/R, glide is the window of difference between the boiling points in blended refrigerants; when you have a refrigerant blend made up of different […]
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Avoiding and Eliminating Callbacks
Callbacks are horrible. They kill the trade from every possible angle. They destroy customer satisfaction and reduce technician morale by causing long hours, resulting in unprofitability for companies and less earning opportunity for everyone. Possibly worse of all, callbacks tell customers that you are no better than their cousin the maintenance man, or worse, the […]
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Laws of Energy and Matter
It's always good to reaffirm some of the basics of energy, work, and matter, as these five rules are some of the most basic and important. The First Law of Thermodynamics States that energy cannot be created or destroyed. It can only change forms or be transferred from one object to another. If you'd like […]
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How to Set a Charge by Superheat
So many techs are OBSESSED with how to set the charge rather than understanding all of the readings, specs, and system conditions that go into optimum system performance. Before “setting the charge,” I suggest (nay, I REQUIRE) that you do a full visual inspection of the system, have an understanding of the initial factory charge […]
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Unconformed Free Chapters
Unconformed Signup * indicates required Email Address * Click HERE for the FPEA Presentation Expanding Your Child's Career Opportunities Here is two free chapters of Unconformed Chapter 1: Papa and Wrecked Planes I’ve got this mental image of my grandfather engraved in my mind's eye. He’s in his office at his aircraft hangar, leaning back […]
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Does Mass or Volume Move Heat?
I once heard someone say, and have since repeated many times that BTU's ride on the back of Cubic Feet of Air or CFM. As I've learned more I've come to the conclusion that the weight or mass of the air passing over the evaporator coil is far more important to understand both in terms […]
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Why is the Air Dry at Altitude?
So, here's the thing. When I was a kid, I got to go skiing in the Rockies a few times. Sounds great, right? Well, yeah, the skiing was fantastic, but the dry air at those higher elevations? the dryness and the lack of oxygen combined felt like breathing vapor beef jerky. Cut to me getting […]
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The Strange Behavior of Moisture in Stuff
Water is weird and water vapor is even weirder – before we dive down this rabbit hole lets define some terms To better understand the behavior of moisture in materials, we need to first define some essential terms and concepts: Relative Humidity (RH): The ratio of the amount of water vapor in the air to […]
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Impacts of Decreasing Evaporator Airflow
Airflow, airflow, airflow… When we set up and commission comfort cooling and heating systems, we need to pay more attention to airflow before worrying about the fancy controls or the refrigerant circuit. One way to do that is by checking out Bill Spohn's Airflow 101 webinar on ESCO Group's learning network, which you can access […]
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