There is a lot of misunderstanding about the HSO (hard shut-off) or “non-bleed” TXV (thermostat expansion valve) and what makes it shut off, why it exists, and how it “magically” opens. Once you understand the forces inside the valve, it is quite simple, obvious, and sadly devoid of any magic. The Three Forces  The TXV […]

When reading ANY article about electrical theory or application, keep in mind that it will only scratch the topic's surface. You can dedicate years of your life to understanding electrical theory and design the way many engineers do and still know just enough to be dangerous. In HVAC, we rarely need to have a DEEP […]

  I walked into a supply house the other day and looked at a “universal” expansion valve on the shelf. The friendly guy behind the counter saw me and walked over. After saying hello, he said: “That's a great valve; it's even balanced port.” Now, I am a bit of a troublemaker. I should have […]