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HVAC School - For Techs, By Techs

Jun 20, 2024

In this episode of the HVAC School Podcast, Bryan interviews Rachel Kaiser, a chemist with a passion for making science more accessible and understandable, especially when it comes to the topic of combustion. Rachel shares her background of how her family's restaurant business sparked her early interest in chemistry and the science behind mixing ingredients to produce desired results.

Rachel dives deep into explaining the fundamental chemistry behind the combustion process. She breaks down the three key components required for combustion to occur - fuel, oxygen, and a heat source - and how the ideal chemical reaction is represented. However, she emphasizes that in the real world, factors like using natural gas (a mixture of gases) as fuel instead of pure methane and air (also a mixture) as the oxygen source lead to incomplete and imperfect combustion reactions.

The discussion highlights the importance of combustion analysis and monitoring for byproducts like carbon monoxide (CO) and nitrogen oxides (NOx). Rachel stresses that testing is crucial not just for technician safety but to ensure proper combustion for occupants as well. High CO levels, for instance, indicate incomplete combustion and the likely presence of other undesirable compounds.

Topics covered include:

  • The chemistry definition of combustion/flame
  • Ideal vs real-world combustion reactions
  • The three requirements for combustion
  • Natural gas as a fuel mixture
  • Air as the oxygen source and mixing considerations
  • Carbon monoxide and nitrogen oxides as byproducts
  • The role of combustion analysis
  • Using visuals/experiments to teach combustion chemistry
  • Applying chemistry knowledge for troubleshooting


Connect with Rachel on LinkedIn and ask her more about chemistry in HVAC HERE. You can also view her presentation from the 5th Annual HVACR Training Symposium and/or purchase your virtual ticket to all sessions HERE.

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