Articles by John Tomczyk

The Professor: Going Chlorine-Free in Retrofits

Ferris State University’s Commercial Refrigeration Laboratory has gone totally chlorine-free. By replacing the refrigerant HCFC-22 that was in two medium-temperature commercial refrigeration cases in the laboratory, the students in the associate degree program in HVACR can boast that the lab is now chlorine-free.
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The Professor: Condenser Splitting

This column focuses on condenser splitting. But first, here’s a quick review of condenser flooding before covering condenser splitting to help all better understand both concepts and their advantages and disadvantages.
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The Professor: More Ice Flake Machine Troubleshooting

This article is part two of a two-part series on ice flake machine troubleshooting.  The last article, which appeared in the Feb. 7 NEWS, examined troubleshooting low and high water levels. This article will examine water impurities and mechanical problems.
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The Professor: Compressor Amperage Data

My Feb. 7 column focused on ice flake machine troubleshooting. I will have more to say on that specific topic in my April 4 column. For this column, I want to take a look at amperage as it relates to HVACR compressors.
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The Professor: Ice Flake Machine Troubleshooting

This article is part one of a two-part series on ice flake machine troubleshooting. This article will examine troubleshooting low and high water levels. Next month’s article will examine water impurities and mechanical problems.
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The Professor: Restricted TXV Metering Device

This article explores how a restricted metering device will affect system performance and efficiency. The system is a commercial refrigeration system with a TXV as the metering device. The refrigerant being used is HFC-134a. Very similar results will occur if an automatic expansion valve (AXV) is used.
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The Professor: Symptom Variations With Different Devices

Symptoms for a refrigeration system with an overcharge of refrigerant are (a) high discharge temperatures, (b) high condenser subcooling, (c) high condensing pressure, (d) higher condenser splits, and (d) slightly higher evaporator pressures. However, these are for a system with a conventional TXV. What if the system has an automatic expansion valve or a capillary tube?
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The Professor: Advanced Leak Detection

My Oct. 4 column discussed leak detection and provided details on basic detection methods. This column looks at more advanced methods. The Oct. 4 column outlined various classes of leaks with standing leaks as the most common. This article begins with a discussion of how to test for pressure-dependent leaks.
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The Professor: Basic Leak Detection Methods

Every environmentally conscious service technician should spend time learning how to check for refrigerant leaks in refrigeration and/or air conditioning systems. Ozone depletion, global warming, and the increasing price of refrigerants are forcing technicians to become better and more thorough leak detectors.
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The Professor: Checking on Refrigerant Overcharge

This column discusses refrigerant overcharge. The check sheet shown depicts a refrigeration system with an overcharge of refrigerant. The system is a low-temperature HFC-134a unit with a TXV/receiver.
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NEWSMakers: Jason Vogelbaugh

Jason Vogelbaugh of Alpha Controls drops in to the NEWSMakers podcast to discuss his role with the company, the InsideIQ Building Automation Alliance, and current energy-efficiency projects being worked on. Posted on Sept. 26.

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