Most of the laws we refer to in air conditioning and refrigeration are pretty obvious and practical. Dalton's law of partial pressures is no exception. John Dalton observed that the air pressure was equal to the added pressures of each gas that make up air. That means that the pressure and density of air can […]

Did you know that electrical terminals have a torque value? Yeah, I didn’t either for a long time. “Tight” worked well enough, but I’ve seen a few connections overheat after a while, and now I wonder… Did you know that tightening electrical screw terminals to their torque specs is part of the NFPA 70/National Electrical […]

Measuring airflow is easy. Measuring airflow accurately is quite a bit more difficult. In many cases, when we as technicians measure airflow, we are trying to get to the almighty CFM (cubic feet per minute) volume measurement. You can take CFM readings fairly easily with a hood, like the Testo 420, but even a hood […]