Air Filter Static Pressure Drop
I'm a big dummy when it comes to my own air conditioning maintenance. I talk about the importance of changing air filters to customers and techs, but I never stay up on replacing my own. Yesterday, I walked into my mechanical room, and my 2-ton air handler sounded like a vacuum cleaner about to implode. […]
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What is Flux?
In HVAC, you will hear the word “flux” used in two totally different parts of the trade. You may have heard of magnetic flux before. Magnetic flux is the lines of force that emanate from a magnet. You often hear about magnetic flux lines in discussions of motor theory. Transformers also use electromagnetic flux to […]
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Finishing Trade School? Some Things you Need to Know
So, I hear you're just finishing trade school. Well done. You chose to take an excellent path, and now your journey is just beginning. How this will go is really up to you, and that's a good thing! You aren't going to be forced in one direction or another; you get to choose. Let's talk […]
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Condensate Switch Controversy
Condensate overflow prevention devices or float switches, as they are often called, are such simple devices that you wouldn't think there would be much room for controversy. In my experience, there are few areas of the trade where technician and installer preferences and opinions vary greatly. Let's start with some float switch basics. Float (condensate) […]
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Start Flowing Nitrogen Sooner
My technician (and brother-in-law), Bert, made a good point. (It's hard for me to admit it, but it's true.) When he needs to open the refrigerant circuit to make a repair, regardless of whether he is recovering or pumping down, he pulls out his nitrogen tank and his regulator. (We like the Western Enterprises VN-500 […]
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Fancy Refrigerant Words
The HVAC industry uses all sorts of fancy words to classify refrigerant. As such, there are all sorts of complicated refrigerant acronyms: HFC, HCFC, CFC. Let's also not forget the mythical zeotropic, azeotropic, and near-azeotropic descriptors. Let's simplify those. (Though if you want to go back to the basics first, check out this article on […]
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The Impact of Adding or Removing Water From Air
Air conditioning was about humidity control from the very start. Willis Carrier's very first air conditioning system was all about controlling the humidity with the side effect that it also could reduce the sensible temperature. Theaters caught on that this newfangled contraption could lead to big summer numbers when they installed it to keep patrons […]
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The Sneaky Effects of Radiant Heat Transfer
If you've ever sat close to a bonfire on a really cold night, you may have noticed that your face starts to get really warm. The minute you put your hands up and shield your face from the light of the flame, your face cools off almost immediately. That happens because the flame is heating […]
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Mistakes in Measuring Ohms
In HVAC and electrical school, one of the first things you learn about electricity is Ohm's law: Volts (V) = Amps (I) x Ohms (R) Pretty simple, right? Watt's law is just as easy: Watts (P) = Volts (E) x Amps (I) With this newfound knowledge, the student walks confidently into the real world with […]
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