Delta T is the difference in temperature between two points of the same medium. It is commonly used by scientists and engineers to analyze the amount of heat transfer in a system. In general HVAC terms, it is the measurable change in temperature between an air input and air output. However, it could also be […]

DISCLAIMER: HVAC School is NOT an official OSHA safety training resource! Although we provide safety tips in good faith, our website is not a substitute for safety training from an authorized OSHA training source. Many things may deter people from working in the HVAC industry. Perhaps surprisingly, exposure to heights could be the deal-breaker. (Not […]

You may have noticed that 3/8″ liquid lines are generally the norm in equipment 5 tons and under. We went to a job where the system had a 1/2″ liquid line, and it got me thinking about the ramifications of going larger or smaller on the liquid line. Liquid Line Basics The liquid line should […]

Brett Wetzel and Kevin Compass from the Advanced Refrigeration Podcast join us to discuss commercial rack refrigeration and identify components. In supermarket racks, we typically have anywhere from 2-5 compressors on a single rack (with multiple evaporators, metering devices, and sometimes even condensers). These compressors may come in several varieties (including screw and scroll) and be digital […]

In this live podcast episode, we have a fun conversation talking with Nathan Orr and Kevin Compass about grocery refrigeration. The most common types of calls are those where the machine is “not making temp.” Usually, the cases can't maintain temperature due to frozen evaporator coils or backed-up drains. On low-temperature/freezer applications, we must rely […]