Understanding Fundamental HVACR Concepts

I thought Mike Murphy’s column on Superheat and Subcooling (“Murphy’s Law: Superheat and Subcooling Important”) in the July 27 edition was great.

I have been in HVACR for about 40 years. The last 10 years I have been teaching at Northern Virginia Community College and our local NAPE (National Association of Power Engineers) chapter. I also wrote a book on commercial refrigeration.

Superheat (SH) and subcooling (SC) is probably the most important, yet least understood, concept in HVACR.

Murphy’s article was interesting, factual, and instructive without being condescending. I think he did a super job of encouraging techs to learn about SH and SC by suggesting “refresh your memory.”

I was shocked by Pat Murphy’s statement that 75 percent of those doing HVACR do not have any formal training. That is worse than I thought.

Dick Wirz
Refrigeration Training Services LLC
Clifton, VA


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Publication date:10/26/2009