As we have mentioned in several previous articles (such as this one HERE), many blended refrigerants have glide, which simply means they boil and condense over a range of temperatures instead of just one temperature. As an example, consider refrigerant R407c. It is a zeotropic blend, which means it has enough glide to make a […]

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 […]

When I first started in the trade, we used to run into shielded control wires on the Carrier Comfort Zone 1 zoning systems and also on a Carrier VVT system I used to maintain at a bank. I knew it has something to do with electrical “noise” and that communicating systems often called for it, […]