Often in commercial HVAC and refrigeration, you'll come across a sight glass/moisture indicator on the liquid line. (Oil sight glasses also exist, but those are different from what I'm talking about today.) Sight Glass The sight glass portion is simple; it's just there to show if the liquid line has a full line of liquid […]

Take a look at the screenshots above. The one on the left is for Death Valley at 282′ below sea level, and the one on the right is Denver, CO, at 5,280′ above sea level. Notice the barometric pressure values; they are almost the same. That means that barometric pressure is corrected or “normalized” to […]

This article is written by one of the smartest guys I know online, Neil Comparetto. Thanks, Neil! Recently, I posted a question in the HVAC School Group on Facebook that went like this: “When designing a residential duct system, what friction rate do you use?” As of writing this, only one answer was correct according […]