Conservation of Energy Law
“Electric Motor energy transformation” by coach_robbo is licensed under CC BY-NC-SA 2.0. Many scientists and philosophers contributed to the discovery of the law of conservation of energy. People have been aware of the concept of energy conservation since ancient Greece. These ancient Greek philosophers, such as Thales of Miletus, believed that all substances on Earth […]
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Sweeping with Nitrogen
Two days prior to this article being published, I sent one out about the popular fallacy that nitrogen “absorbs” moisture. That tech tip went out at 7 PM eastern time like usual, and I was sitting on the couch watching something on the Food Network (as usual). At 7:10 PM, I get a call on […]
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5 Install Mistakes that Kill Systems
When we install systems, we should have three main goals in mind: maximizing longevity, efficiency, and capacity. We want our units to work as long as possible, use the lowest amount of energy, and move the greatest amount of BTUs possible with a proper mix of sensible and latent heat transfer. Unfortunately, some installation practices […]
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Learning from the Past vs. Allowing it to Control You
In our line of work, it's all too easy to let your bad experiences inform your present and future experiences. That is especially true if you have a high emotional range. Having “emotional range” is a polite way of saying that you're a bit up and down (maybe even neurotic). We don’t believe that sensitivity […]
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Fan On or Fan Auto
Full disclosure: as a technician, I was guilty of setting the fan to “on” at the thermostat for many years. I never really thought of any of the negative impacts that could happen. I wanted to circulate the air and keep air moving through the high-efficiency air filter that most of our houses had. Later, I […]
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What is Inductive Reactance?
Ohm’s law is pretty straightforward; you multiply ohms by amps to get the voltage. Using variable E to represent voltage, variable I for amps, and variable R for ohms, the equation for Ohm’s law looks like this:  E = I × R  You can figure out the number of amps in a system using basic […]
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What’s the Difference Between 208v and 240v?
The easy answer is 32v. Class dismissed. I’m only joking, of course. Finding the difference between 208 and 240v power supplies may sound quite simple, but there are some pretty sharp fundamental differences. Apart from the obvious differences in overall voltage, 208 and 240v power supplies use the electrical company’s power differently. The motors also […]
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Air Velocity Quick Tips
Recommended Duct Velocities (FPM) Duct Type Residential Commercial / Institutional Industrial Main Ducts 700 – 900 1000 – 1300 1200 – 1800 Branch Ducts 500 – 700 600 – 900 800 – 1000   As service technicians, we are often expected to understand a bit about design to diagnose a problem fully. Duct velocity has many […]
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How to Replace a Condensing Fan Motor
Service calls about condensing fan motor failure are quite common. Even though fan motor replacement is a standard procedure for residential split systems, it requires careful attention to safety and detail.  This article will give you a step-by-step guide to replacing condensing fan motors. Along the way, we will also explain a few best practices […]
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