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The place to learn some things you've forgotten
along the way, as well as remind you,
of some things you forgot to know in the first place.


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Bryan Orr

BRYAN ORR

Co-Founder and President at Kalos Services, Bryan has been involved in HVAC training for over 13 years. Bryan started HVAC School to be free training HVAC/R across many mediums, For Techs, By Techs.


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Check our latest Tech Tips

What does "RES" mean on a contactor or relay?
Go to your truck, pick up a contactor, and look at it closely. You may find some interesting ratings you never noticed—things like terminal ambient temperature ratings and torque specs. One reading you may overlook is the RES AMPACITY of the contactor or relay. The RES rating is the RESISTIVE LOAD AMPACITY (amperage capacity) or rating. […]
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The Unexpected Result of Series Circuits
When I teach electrical basics, we do this exercise where we sit down and connect a 10-watt bulb to a power supply and through a switch. It's a SUPER SIMPLE circuit—the kind you might have learned about in a high school science class. But then I grab another 10-watt bulb and tell them to connect […]
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The Friction Rate Chart (and What it Means)
A lot of proper duct design comes down to an understanding of available static pressure and friction rate. We've covered this topic several times on this site and the podcast, but I wanted to focus on this ACCA chart specifically (shown above). If you want a deep dive, I highly recommend listening to my podcast […]
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