When I started in the trade, the idea of flowing nitrogen while brazing was nothing more than the punchline of a joke. Like pulling a vacuum with a micron gauge or proper recovery, it was a wink and nod proposition rather than a real practice. I've had to unlearn many bad habits since those early […]

The Four Ps of IAQ I’m not the first, second, or probably even the thirty-second person to write about improving indoor air quality problems using the four Ps approach. It’s a well-known thought process in the building science community—not sure if that’s the case in HVAC circles. The first P is for pollutants. In this […]

The chart above is from a Carrier heat pump, and it lists some common accessories. I have heard this common pressure switch (last on the list) called a low-pressure switch (because it opens on fall in pressure) and a high-pressure switch (because it's in the liquid line), but RARELY do I hear it called its […]