#Superheat

So many techs are OBSESSED with how to set the charge rather than understanding all of the readings, specs, and system conditions that go into optimum system performance. Before “setting the charge,” I suggest (nay, I REQUIRE) that you do a full visual inspection of the system, have an understanding of the initial factory charge […]

As we discussed in an earlier podcast, a TXV maintains a specified and constant superheat at the evaporator coil outlet. It does this through a balance of forces between the bulb pressure (opening force), equalizer pressure (closing force), and spring pressure (closing force). We can actually adjust the spring pressure on some valves. But why […]

First off, if you've never heard the term “beer can cold,” you are either not in the trade, or you have been living a pretty sheltered existence. I started as a tech apprentice when I was 17 years old, and on my first day in the truck, my trainer grabbed the suction line of a […]

I was fresh out of school, working as an apprentice at my first real HVAC job, and I was listening in on a shop conversation between a few techs. They were talking about finding so many overcharged systems. One of the techs turns to me and says, “I had a unit yesterday that was so […]

  The most common—and often most frustrating—questions that trainers and senior techs get asked sound something like this: “What should my ______ be?” or “My _____ is at ______. Does that sound right?” Usually, when the conversation is over, both the senior and junior techs walk away feeling frustrated because the junior tech just wanted […]

Suction pressure, head pressure, subcooling, superheat, delta T. Taking all five of these calculations into account on every service call is critical. Even if you must do further diagnostic tests to pinpoint the problem, these five factors are the groundwork before more effective diagnostics can be done. I would also add static pressure as an […]

Jim Bergmann and I recorded a podcast for HVAC School that covered when and how to check the refrigerant circuit without connecting gauges. Listener Joe Reinhard listened several times and wrote up this summary of what he gained from the episode. I edited it lightly, but most of this is his work. Thank you so […]

In this episode of HVAC School, Bryan talks to Leslie about the deceptive TXV. Thermostatic expansion valves, also known as TXVs or TEVs, are metering devices that maintain superheat. They contain an external equalizer. External equalizers give the pressure reading that you would normally take with a suction gauge at the end of the evaporator […]

In this episode of HVAC School, Bryan covers the “5 pillars of refrigerant circuit diagnosis” and why they matter. They are: Superheat Subcool Suction pressure Head pressure Air temp split (delta T)   These 5 readings give you a holistic idea of the A/C system. Instead of getting hooked on checking only superheat and subcool […]

In this episode, Bryan goes back over the basics and stresses the importance of diagnosing the whole system. I'll cut to the chase: inspection is NOT overrated. Inspections help you become more familiar with HVAC systems and can help you catch on to minor issues before they spiral out of control. Check air filters, check […]

In this episode of the HVAC School Podcast, Bryan talks with Jeremy Smith about refrigeration tips, terms and processes. They also cover the similarities and differences between A/C and refrigeration. Being on-call as an A/C tech is not all that different from being on-call as a refrigeration tech. Similarly, the principles of heat transfer don't […]