BACK

#Transcritical

Tech Tips:

This tech tip is based on a podcast with Andre Patenaude from Copeland. You can listen to that podcast episode HERE, and we encourage you to check out some of the resources at the end of this tech tip—whether you’re all in on ramping your team up for CO2 or just CO2-curious. Carbon dioxide (CO2) […]

Triple Point In Water and CO2 w/ Andrew G. and Matthew T.

In this episode, Bryan is joined by Matthew Taylor, a supermarket refrigeration specialist whose expertise centers on CO₂ rack systems, and Andrew Greaves, Director of User Experience at NAVAC Tools, for the third installment of their series on triple-point evacuation. The conversation expands beyond water to bring CO₂ into the picture, exploring where the […]

How Do You Ramp Up Your Team to Effectively Service and Support CO2 Applications?

In this informative episode, Bryan Orr speaks with Andre Patenaude from Copeland about CO2 refrigeration systems. They dive deep into the unique characteristics and challenges of working with CO2 as a refrigerant, providing valuable insights for HVAC and refrigeration professionals looking to expand their knowledge in this growing field. Andre explains the reasons behind […]

CO2 Introduction Podcast & Resources

In this episode of the podcast, Bryan talks with Andre Patenaude from Emerson about CO2 refrigeration, and transcritical booster systems. Modern CO2 systems are efficient and effective due to their electrical controls and components, including case and high-pressure controls. Carbon dioxide (CO2) is a good refrigerant to address global climate change. From a sustainability standpoint, […]

Alan Welsh
#co2 #Transcritical

Check out our most recent video

How to Evacuate an AC system, Full Vacuum Procedure

Our latest Podcast

HVAC School – For Techs, By Techs

Real training for HVAC ( Heating, Ventilation, Air Conditioning and Refrigeration) Technicians. Including recorded tech training, interviews, diagnostics and general conversations about the trade.

In this short episode, Bryan and Roman talk about the psychrometrics of a hidden moisture failure… behind the drywall. Roman had an indoor air quality and mold assessment in his own home, and he learned that there were active mold spores in his home; he shares what he learned from the experience.

Roman had a bulk water issue from plumbing (though bulk water issues can also occur outside the building or from condensate drainage problems). Walls are NOT solid; they have plumbing and insulation inside, and the air spaces between the walls support a microclimate when moisture is in there, regardless of whether it’s water vapor or bulk water. In Roman’s case, the bulk water failure came from the plumbing leak; it saturated the slab for half the house. The water was absorbed by the concrete, and any surface that touched the concrete transferred that water over time.

The mold assessor used two different devices. The pin-type meter punctured the surface of wood or drywall and measured the resistance between the probes (water transfers electrons between them); the measurement revealed the water quantity. A pinless meter determined the source of the failure via high-frequency radio waves, and it measured the capacitance to determine whether moisture was present within or behind the surfaces. The results showed that water was behind tile, baseboards, and drywall.

Thermal imaging has also proven to be a useful tool to see the cooling effect that occurs when water evaporates from liquid to vapor inside a wall, but the cold spots go away when the space thermally equalizes. While HVAC professionals cannot assess mold, we can use tools like thermal imaging to help determine when it’s time for a customer to call someone who can help; we are still responsible for our customers’ health and comfort in their homes.

Learn more about building science concepts, especially moisture and its effects on buildings and comfort, from the Building Science Corporation’s many great resources at https://www.buildingscience.com/.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool

Purchase your tickets or learn more about the 8th Annual HVACR Training Symposium at https://hvacrschool.com/symposium.

Subscribe to our podcast on your iPhone or Android.

Subscribe to our YouTube channel.

Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android.

Search Episodes

Behind the Drywall – The Psychrometrics of a Hidden Moisture Failure – Short #298

08/11/2026

Bryan Orr

HVAC Education. What NOT to Do w/ Jim F., Roman B. and Craig M.

08/06/2026

Bryan Orr