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A Steam Heat Primer by Dan Holohan (Podcast)

By Bryan Orr

In today's podcast episode, Bryan gives an audio recording of the legendary Dan Holohan's article, “A Steam Heat Primer.”

Read that article HERE.

Check out more about Dan's work at heatinghelp.com.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

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Author:

Bryan Orr

Company: HVAC School

Position: Founder

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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 essential episode, Bryan sits down with Jeff and Tom from Copeland to dive deep into the world of scroll compressors and the critical topic of refrigerant compatibility. As the HVAC industry navigates new refrigerant standards and regulations, understanding how compressors are specifically designed and optimized for different refrigerants has never been more important.

The conversation begins with a comprehensive overview of refrigerant classifications, focusing on the A1, A2L, and A3 categories that technicians are encountering in the field. Jeff and Tom dispel common misconceptions, particularly around A2L refrigerants and their relationship to propane (R-290), clarifying that A2L refrigerants like R-454B and R-32 do not contain propane despite widespread confusion in the industry. They explain how regulatory pressures around Global Warming Potential (GWP) limits are driving the transition to these new refrigerants, with targets under 700 GWP for air conditioning applications.

The technical discussion covers the fundamental operating principles of scroll compressors and why they’ve become the dominant technology in HVAC applications. With over 200 million scroll compressors sold by Copeland, the technology has proven its reliability and efficiency. However, the guests emphasize a crucial point that many in the industry overlook: each compressor is specifically optimized for particular refrigerants. This isn’t just about basic compatibility – it’s about precision engineering to meet efficiency requirements and ensure long-term reliability. The scroll geometry, oil viscosity, and internal components are all carefully matched to each refrigerant’s unique properties.

Safety takes center stage throughout the discussion, with both guests stressing that while A2L refrigerants are “mildly flammable,” they require heightened safety practices that were previously considered best practices but are now mandatory. This includes nitrogen purging during brazing, proper evacuation procedures, comprehensive leak testing, and thorough documentation. The conversation also touches on the practical challenges contractors have faced, including refrigerant availability issues, while maintaining the importance of following proper procedures regardless of supply chain difficulties.

Topics Covered:

Refrigerant Classifications: A1 (non-flammable), A2L (slightly flammable), and A3 (flammable) categories and their safety implications
Compressor Optimization: How scroll compressors are specifically engineered for each refrigerant, including R-454B and R-32 applications
New Compressor Naming Conventions: Introduction of “Y” series compressors for A2L and A3 refrigerants, replacing the traditional “Z” series
Oil Viscosity Requirements: Different POE oil specifications (32 vs 46 viscosity) for various refrigerants and temperature conditions
Safety Protocols: Enhanced safety requirements for A2L refrigerants, including mandatory nitrogen purging and leak testing procedures
Glide Characteristics: Understanding temperature glide in R-454B (2.4 degrees) versus single-component R-32
Refrigeration Applications: Multi-refrigerant capability in commercial refrigeration compressors and natural refrigerant trends
Service Compressor Strategy: LX series compressors designed to cover multiple R-410A applications for aftermarket needs
Regulatory Timeline: Upcoming January 1, 2026 GWP limits for supermarket refrigeration systems
Tools and Resources: Copeland Mobile app for compressor selection, cross-referencing, and technical specifications
Training Importance: Critical need for enhanced technician education and OEM-specific training programs

Visit the EPA’s website to stay up to date on the latest HFC phasedown rulings and information at https://www.epa.gov/climate-hfcs-reduction.

Keep up with Copeland at https://www.copeland.com/ and on their Facebook, LinkedIn, and Instagram.

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 7th 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

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Scroll Compressors & New Refrigerants w/ Copeland

09/11/2025

Bryan Orr

Leaky Ducts = Sweaty Houses – Short #256