Author Archives: Ron Walker

Technician Certification

One of the most frequently asked questions I receive is about the EPA certification (HVAC Certification) and the different types of certification. Two items of note: Apprentices are exempt from certification requirements provided they are closely and continually supervised by a certified technician. The EPA exams certify you but do not, by any means, prepare you…

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Coming Soon – HVACTraining.TV

It has been months in development, but we are very close to launching HVACTraining.TV. Throughout the years I have received many requests for stand alone online HVAC training that HVAC contractors can use for group training. While our online courses are designed to help standardize the training of your techs and provide a career path, it…

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Nitrogen Purging and Brazing

Most HVAC installation instructions require flowing nitrogen through the copper tube during brazing. This is an important step in producing a quality HVAC system. Why nitrogen purge? Oxygen in the air combines with copper to form surface copper oxide. We see this on copper tube as a light to dark brown discoloration. You’ve probably seen ACR/medical gas…

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Current Relays Commercial Refrigeration

On start-up, the amp draw of the compressor is near LRA before the rotor starts to turn. The high current in the power leg going from M, through R, to the run winding, energizes the relay coil between terminals L and M. The coil pulls in the normally open (NO) contacts L and S. Line voltage…

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Motor Starters – Video

A motor starter is basically a contactor with overloads . The overloads in the starter are selected according to both the voltage and the RLA of the compressor. These protectors respond to a change in heat caused by voltage drop and amperage increases. If the starter senses an overload condition in any one of the motor…

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