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Tech Tips:

Evaporator coil leaks are a fact of life in the industry. (We could have a long and lively discussion about how evap coils aren’t made like they used to be, but that’s for another day.) When you have an evaporator leak on a system, you’ll have two choices to fix the problem: replace the coil […]

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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.

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In this episode of the HVAC School podcast, Bryan sits down with Ray Wohlfarth, a seasoned HVAC contractor and prolific author who has dedicated over 30 years to mastering the art and science of boiler systems. What began as a competitive disadvantage—competitors claiming he knew nothing about boilers—became Ray’s driving passion. Through daily reading, countless mistakes, and an unwavering commitment to learning, Ray transformed himself into one of the industry’s most respected voices on hydronics and steam systems.

Ray shares the personal story of how legendary author Dan Holohan literally “saved his marriage” with his book on one-pipe steam systems. When Ray and his wife moved into their first house with steam heat, mysterious banging sounds threatened domestic harmony until Dan’s book provided the answers Ray desperately needed. This experience inspired Ray to pay it forward, eventually authoring 14 technical books himself—all written with the vision of a technician stuck in a boiler room at 9 PM on a Friday night, frantically searching for solutions.

The conversation dives deep into practical wisdom earned through experience. Ray emphasizes the critical importance of safety in boiler rooms, recounting a harrowing story of a hospital engineer who bypassed safety controls and manually lit a boiler with a flaming broom—resulting in dangerous explosions. He stresses that technicians should always identify escape routes before beginning work, as a lifting relief valve can quickly fill a room with steam, displacing oxygen and eliminating visibility. Beyond safety, Ray shares diagnostic techniques like listening for dripping, hissing, or the “Rice Krispies” sound that indicates scaling, and visually inspecting for soot streaks that reveal combustion problems and potential carbon monoxide issues.

Throughout the episode, Ray’s philosophy shines through: humility, continuous learning, and the joy of solving complex problems. Whether discussing the holistic nature of steam system troubleshooting, the importance of water quality treatment, or the surprising efficiency of properly designed steam systems (like the LEED Gold-certified Empire State Building), Ray’s expertise and passion are evident. His advice for aspiring boiler techs is simple but profound: read 15 minutes daily about your industry, engage with online communities like HeatingHelp.com, and never stop learning from every service call.

Topics Covered

Ray’s Journey: Transitioning from Carrier air conditioning to boiler expertise over 30+ years
The Writing Process: Creating 14 technical books designed specifically for technicians in the field
Dan Holohan’s Influence: How Dan’s books and mentorship shaped Ray’s career and literally saved his marriage
Boiler Room Safety: Critical importance of identifying escape routes and recognizing dangerous practices
Diagnostic Techniques: Using your senses—listening for dripping, hissing, and scaling sounds; looking for soot, leaks, and discoloration
Near-Boiler Piping: Why 90% of steam boiler installations have incorrect piping and the importance of proper insulation
Steam vs. Hydronic Systems: Key differences in troubleshooting approaches and why steam operates more like air conditioning than hydronic
One-Pipe vs. Two-Pipe Steam: Fundamentals of steam system design, traps, and venting behavior
Condensing Boilers: The reality of “conditional condensing” and why 95% efficiency requires specific return water temperatures
Radiant Heat Comfort: Why hydronic radiant heating provides superior comfort compared to forced air
Water Quality Issues: The critical importance of water treatment, the mystery of deteriorating fittings, and potential chlorine impacts
Learning Resources: The value of HeatingHelp.com, reading 15 minutes daily, and engaging with online communities
Ray’s Book Series: Overview of his “Lessons Learned” series and specialized books on brewery boilers and wiring diagrams
Common Mistakes: Real-world troubleshooting stories including the mystery of the 2-degree delta T and lessons in humility

Check out some of Ray’s boiler books on Amazon HERE. His latest book, Lessons Learned: Understanding Boiler Wiring Diagrams, is available HERE.

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.

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

Search Episodes

Learning Hydronics, Boilers and Steam w/ Ray Wohlfarth

11/06/2025

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How Duct Tape Got Its Name (and Why It Shouldn’t Be on Ducts) – Short #264

11/04/2025