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. Although we primarily work with our hands, our eyes are one of our most valuable assets in the industry. After all, […]

To answer the question in the title, we use it as a measurement of pressure. REALLY, it is a measurement of distance. First, any scale CAN be used to measure vacuum (negative pressure) and positive pressure. The trick is knowing which is best suited for which and the size of the scale. Larger units of […]

We all see a lot of questions about dyes, leak stoppers, lubricants, inhibitors, and snake oil. All of those were designed to go into the refrigerant circuit and “improve” something. I just go back to what Ray Johnson always said. (Ray is one of my early heroes in the biz, and he taught me a […]