Oil Best Practices for HFC and HFO-based Systems
This tech tip was written by Don Gillis with Chemours. Thanks, Don! The shift to R-410A from R-22 brought some pretty big changes to the industry, including the shift to polyolester (POE) oil. We had been using mineral oil for CFC refrigerants like R-12 and HCFCs like R-22, so we had to update some of […]
Read more
Glide at Static Pressure
Source: Refrigerant Slider in the Ref Tools App We’ve been pretty spoiled in residential and light commercial HVAC in the USA because we haven’t needed to deal with glide much. In HVAC/R, glide is the window of difference between the boiling points in blended refrigerants; when you have a refrigerant blend made up of different […]
Read more
Sizing Return Grilles
A few weeks ago, I spent several days redoing a duct system and replacing a furnace for a friend. I had static pressure readings from before the system was replaced, and with the new furnace that I had picked out, I had created a static pressure budget and felt confident I could significantly lower the […]
Read more
Under Pressure
A few weeks ago, I was hired to consult on a multi-family new construction project.  The building was already framed, and the ducts were roughed in.  The owner of the building was concerned with the quality of the ductwork.  He noticed that the HVAC company was not following the mechanical engineer’s plans. This was my […]
Read more
Refrigerant Recovery Practices
Recovery is the removal of refrigerant from a system. From there, you can either store it and send it in for recycling or reintroduce it back into the same system. Here are some top tips: Make sure your tank is empty and evacuated to 300 microns if you plan to return the refrigerant to the […]
Read more
What Airflow Goes Around HAS to Come Around
Have you ever woken up early on a Saturday morning and thought to yourself, “I really wish I knew how to size transfer grilles and jumper ducts properly?” I know I have. Although come to think of it, I believe it was a Friday morning.  Properly sizing transfer grilles is something I have been wanting […]
Read more
Common Causes of Compressor Failure
This article was written by Don Gillis, the technical training manager at Chemours. Thanks, Don! Refrigerant compressors are essential components of air conditioning and refrigeration systems, as we all know. They work by compressing refrigerant vapor, which then flows through the system and changes state as pressure and temperature conditions rise and fall. Unfortunately, these […]
Read more
Training: Processes or Apprentices?
“It is only through the enforced standardization of methods, enforced adoption of the best implements and working conditions, and enforced cooperation that this faster work can be assured. And the duty of enforcing the adoption of standards and enforcing this cooperation rests with management alone.”  —Frederick Taylor “The objective of education is not to fit […]
Read more
Sales: Techniques or Values?
“The very substance of our existing which has made us leaders in technique, stands as a barrier to any thinking which might be able to comprehend technique from beyond its own dynamism.” -George Grant The odd quote above takes some time to understand but has been rattling around in my brain for weeks now. George […]
Read more

To continue you need to agree to our terms.

The HVAC School site, podcast, and tech tips are
made possible by generous support from