The topic of static pressure comes up frequently in HVAC, and it’s sometimes presented as a test that can be all-knowing and insightful about what is happening with regard to airflow in a system. To use static pressure responsibly, we need to understand what it really is and what it means for an HVAC system. […]

  Flowing nitrogen while brazing and pressurizing with nitrogen are great practices. Putting nitrogen in with the refrigerant? Not so much. Nitrogen is a “non-condensable” gas because it cannot be condensed (under normal conditions). However, nitrogen is just one of the non-condensables. First, let's talk about what a non-condensable gas is. Any gas that does […]

Fan laws and fan curves are a deep subject with a lot of nuance and variation. Just to get our heads around the subject, let's focus on two different types of fans that we see all the time in HVAC: the prop/axial type and the radial/centrifugal type. Centrifugal/Radial As we increase the pressure differential across […]