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Tech Tips:

On an energized, intact circuit, you will read voltage across an OPEN switch when testing with a voltmeter. However, you probably won't read significant voltage across a CLOSED switch. Both sides of a closed switch are electrically identical (or at least very close). Therefore, there should be no movement of electrons between the leads of […]

Open and Closed Case

I know I'm gonna get some eye-rolling here, but it needs to be said. When we teach electricity to new techs, we use a lot of “water” metaphors. We talk about volts like PSI, amps like flow, and watts like GPM (speaking of GPM in HVAC, check out our article on hydronics HERE). Even the […]

Bi-metal & Magnetic Switches – Short #252

In this short podcast episode, Bryan covers some basics on bi-metal and magnetic switches. Bi-metal switches are made of two dissimilar metals that are bonded together and are often integrated into motors. When the temperature changes, the metals bend. In an overload circuit, they're designed to bend and open the circuit in an overheat […]

bennydenham58
#current #switches #volt #voltage #voltmeter

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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 episode from the 6th Annual HVACR Training Symposium, Brynn Cooksey, a home performance contractor from Michigan and technical training business owner, reveals how indoor air quality (IAQ) testing transformed his contracting business from a commodity service into a profitable specialty. Cooksey shares his proven methodology for turning IAQ into an “instant profit center” by implementing systematic testing on every service call.

Cooksey opens with a striking reality check: according to the EPA, Americans spend 90% of their time indoors, yet indoor air quality is 2-5 times worse than outdoor air. This presents a massive opportunity for HVAC contractors, as he explains that consumers are already spending $10 billion annually on air quality products at big box stores – but they’re treating symptoms rather than addressing root causes. His approach involves educating contractors on how to position themselves as the solution providers rather than letting customers self-diagnose with retail products.

The presentation dives deep into six critical IAQ parameters that every contractor should measure: particles (especially dangerous PM 2.5), volatile organic compounds (VOCs), carbon dioxide, carbon monoxide, humidity, and temperature. Cooksey emphasizes his “test in, implement solution, test out” methodology, demonstrating how this systematic approach not only ensures customer satisfaction but also provides concrete proof of value delivered. He shares real-world examples, including a dramatic case where routine IAQ testing during a water heater service call revealed a cracked heat exchanger that could have been life-threatening.

The episode concludes with extensive coverage of ventilation strategies, which Cooksey calls the “silver bullet” for IAQ improvement. He walks through the differences between supply-only, exhaust-only, and balanced ventilation systems, strongly advocating for Energy Recovery Ventilators (ERVs) as the optimal solution. His practical approach includes using DOE’s free REDCalc tool for proper ventilation sizing and emphasizes the importance of controlled ventilation over relying on natural air leakage – debunking the myth that “houses need to breathe.”

Topics Covered

The IAQ Business Case: How testing indoor air quality on every service call creates new revenue streams and differentiates contractors in a commoditized market
Six Critical IAQ Parameters: Detailed explanation of particles (PM 2.5), VOCs, carbon dioxide, carbon monoxide, humidity, and temperature – what they are, how to measure them, and health impacts
Systematic Testing Methodology: The “test in, implement solution, test out” approach that provides measurable results and customer proof of value
Particle Control Strategies: Source control, enhanced filtration (MERV 13-16), duct cleaning benefits, and duct sealing with Aeroseal technology
Chemical and VOC Management: Understanding formaldehyde and benzene sources, proper storage techniques, and why PCO devices aren’t recommended
Carbon Monoxide Detection: The life-saving importance of testing every home, understanding chronic vs. acute exposure, and why standard CO detectors aren’t sufficient
Ventilation as the Silver Bullet: Comprehensive coverage of supply-only, exhaust-only, and balanced ventilation strategies, with strong emphasis on ERV systems
Practical Implementation Tools: Using DOE’s REDCalc tool for ventilation sizing, integrating IAQ testing into service calls, and customer communication strategies
Real-World Case Studies: Multiple examples of IAQ testing uncovering dangerous conditions, from cracked heat exchangers to improper combustion appliance installation
Building Science Integration: How IAQ testing leads to broader building performance improvements, including duct sealing, insulation, and equipment sizing corrections

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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Search Episodes

IAQ for the HVAC Technician w/ Brynn Cooksey

08/14/2025

Bryan Orr

Bi-metal & Magnetic Switches – Short #252

08/12/2025

Bryan Orr