HVAC School - For Techs, By Techs

In this episode of the HVAC School podcast, Bryan Orr sits down with Adam and Matt to tackle one of the most misunderstood aspects of HVAC system design: return air systems. The conversation dives deep into the common myths surrounding returns, particularly the widespread belief that adding returns to rooms will automatically improve comfort and air mixing. The hosts explore why returns are often seen as mysterious - sometimes helping when added to a room, sometimes making things worse - and work to clarify the actual science behind how returns function versus how many technicians think they work. The discussion reveals a fundamental misunderstanding in the industry about the difference between supply and return air behavior. While supply air creates significant mixing effects through entrainment and the Coanda effect, returns have a much more limited impact on room air patterns. According to Manual T, laboratory tests show that return air intake influence is limited to just a few feet around the grille, even at high velocities. This leads to the key insight that returns serve primarily as pressure relief mechanisms rather than air mixing devices, which explains why their placement and sizing strategies differ significantly from supply air design principles. The hosts examine real-world scenarios, including Matt's experience with a two-story home where the homeowner requested an additional return on the second floor despite having adequate return pathways. They discuss the Manual D recommendation for returns on each floor while sharing field experiences where single central returns have successfully maintained temperature differentials within two degrees across multiple floors. The conversation emphasizes that proper system design, including accurate load calculations and right-sized equipment, often eliminates the need for complex return strategies. A significant portion of the discussion focuses on the practical considerations of passive versus active returns. The hosts lean toward passive return strategies (transfer grilles, jumper ducts, and door undercuts) for their simplicity, cost-effectiveness, and reduced ductwork requirements. However, they acknowledge the challenges of proper sizing - passive returns must be significantly larger than their active counterparts since they rely on minimal pressure differentials rather than mechanical assistance. The conversation also addresses privacy concerns with transfer grilles and the benefits of oversized jumper ducts for noise attenuation. Key Topics Covered Common Return Myths Debunked The belief that adding returns automatically improves room comfort Misconceptions about returns mixing air effectively The difference between supply air entrainment and return air influence Pressure Relief vs. Air Mixing Returns function primarily for pressure balancing, not air circulation How to measure pressure problems using flow hoods and micromanometers The impact of door closure on supply air delivery Manual D Guidelines and Field Reality Manual D recommendations for returns on each floor Real-world examples of successful single central return systems When to follow guidelines versus when field conditions allow flexibility Passive Return Strategies Transfer grilles, jumper ducts, and door undercuts as alternatives to active returns Proper sizing considerations for low-resistance return pathways Privacy and noise concerns with different passive return methods System Design Fundamentals The importance of accurate load calculations in reducing return requirements How right-sizing equipment reduces airflow and pressure management challenges The relationship between static pressure and airflow changes Zoning Considerations Whether to add dampers to returns in zoned systems Potential depressurization issues when zones are closed Passive solutions for zoned system return air management Practical Installation Tips Avoiding short-cycling by maintaining proper supply-to-return distances The risks of undersized return pathways Balancing damper selection and sealing strategies Advanced Concepts Destratification strategies using ceiling fans versus high returns The impact of conditioned versus unconditioned return air pathways Energy efficiency considerations in return system design   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

If you're a fan of fans, this is the podcast for you! In this short podcast episode, Bryan shares how installing ceiling fans can be a smart HVAC design strategy (even though he wasn't a fan of fans!). Ceiling fans break the "don't blow air on people" rule we usually refer to in duct design, but they can solve quite a few basic comfort problems, especially in homes with lower loads than we've historically seen. They're great for creating high-velocity airstreams and mixing air. Low-load homes have systems with lower tonnages; they don't move as much air and could use a little bit of help from a ceiling fan. Air mixing is also poor in homes that have a greater distance between the air and the ceiling. Stratification of the air causes comfort problems due to temperature differences, and hot or cold surfaces can also contribute to these issues for similar reasons. Moisture and eventual growth are also concerns when we allow rooms to have those temperature differences (especially on the ceiling, as water vapor is lighter than air). Ceiling fans disrupt the stratification of air and water vapor. They solve air mixing problems while they dispel odors and maintain more consistent dew points throughout the air. Modern fans with ECMs can also run at a low speed without taking a large energy efficiency hit. Ceiling fans are great and relatively inexpensive solutions that can solve comfort and IAQ problems in high-performance homes.   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

In this episode of the HVAC School podcast, Bryan Orr sits down with Roman Baugh, a leading VRF (Variable Refrigerant Flow) specialist and co-host of the VRF Tech Talk podcast, for an in-depth exploration of VRF system maintenance. The conversation begins with some lighthearted back-and-forth before shifting to the technical realities of maintaining VRF equipment. Roman immediately addresses a common misconception: the idea that VRF systems are “maintenance free.” He explains that, contrary to some marketing claims, these systems require regular, specialized attention to ensure longevity and reliable performance. Roman shares real-world stories that highlight the consequences of poor installation and lack of serviceability. He describes situations where VRF units are installed in hard-to-reach locations—like cabinets or hard-lid ceilings—making even basic maintenance a costly and invasive process. This lack of foresight often leads to significant expenses for property owners, especially when major repairs require extensive drywall work just to access failed components. Roman emphasizes that proper maintenance starts with ensuring that systems are accessible and serviceable, a step too often neglected during installation. The discussion delves into the specifics of VRF maintenance, moving beyond the basics of filters and drain lines. Roman explains how improper drain line installation can lead to persistent error codes and system shutdowns, particularly when condensate pumps are forced to exceed their design limitations. He goes on to detail the critical role of temperature sensors (thermistors), which are prone to failure from corrosion, moisture, and environmental factors—especially in challenging locations like laundry rooms. These sensor failures can cause misleading error codes and even compressor damage if not addressed promptly. Roman recommends regular sensor checks, especially as components age past their typical five-year lifespan. A significant portion of the episode is dedicated to electronic expansion valves (EEVs), which are susceptible to rust, dried grease, and mechanical binding. Roman advocates for proactive inspection and, when necessary, preemptive replacement of EEVs to prevent catastrophic compressor failures. He introduces tools developed by technicians for technicians, such as the EEV Mate and custom EEV magnets, which allow for manual manipulation and diagnostics of expansion valves in the field. These innovations help HVAC professionals quickly triage and resolve issues, minimizing downtime and protecting expensive system components. The episode wraps up with a strong endorsement for ongoing education, technician communities, and the use of specialized tools and software to ensure VRF systems are maintained to the highest standard. Topics Covered: Debunking the “maintenance-free” VRF myth Access and serviceability challenges in VRF installations Proper drain line design, installation, and common failure points The role and failure modes of temperature sensors (thermistors) Environmental impacts on sensor and component reliability Electronic expansion valve (EEV) maintenance and troubleshooting Field-developed tools for EEV diagnostics (EEV Mate, EEV magnets) The importance of commissioning and using service software Application and installation quality as a foundation for long-term reliability Technician communities, podcasts, and resources for VRF learning and support This episode is essential listening for HVAC professionals seeking to deepen their understanding of VRF systems, avoid common pitfalls, and stay ahead with practical, field-tested maintenance strategies. For more insights, check out Roman Baugh’s VRF Tech Talk podcast and YouTube channel for additional resources on VRF technology and troubleshooting.   Check out the VRF Tech Talk podcast on YouTube HERE, or search for it on your favorite podcast app. 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

In this short podcast episode, Bryan explores the maintenance mindset. Maintenance procedures require a different skill set from troubleshooting, especially the customer service mindset and dedication to execution. Good maintenance is important, and it may be "boring" to some techs, but it provides value and is worth doing well. Clients purchase maintenance plans for better reliability and efficiency. Several also enjoy the health benefits of cleaner HVAC systems. The key to maintenance is having a "do no harm" mindset and a commitment to delivering value. A sales-oriented mindset should take a back seat to giving the equipment a thorough cleaning and making sure it's in proper working order; we don't want to upsell bolt-on IAQ products. Maintenance procedures are really about preventing problems and cleaning.  To give the equipment a thorough cleaning, you must pull the top off the condenser and wash it well. You may have to pull a blower wheel (which may be a quotable procedure). Good maintenance techs take pride in these types of cleaning procedures and ensure that they leave the equipment in better condition than they found it. Problem prevention is another aspect of the maintenance mindset. When you're thorough, you find things that can be fixed or adjusted to benefit the system, whether it's a wire rubout, a failing crankcase heater, a poorly fitted filter with significant bypass, or something else. Spotting and addressing these issues early requires technical expertise (just like troubleshooting) and is of excellent value to the customer.    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

In this episode of the HVAC School podcast, Bryan welcomes back Brynn Cooksey from Air Doctors and HVAC U to discuss critical topics facing the HVAC industry today. Brynn brings his unique perspective as both a successful contractor in southeast Michigan and an industry educator who has made the transition to focusing primarily on workforce development and training. The conversation begins with a deep dive into indoor air quality (IAQ), where Brynn challenges the common industry approach of throwing products at problems without proper testing. He emphasizes that effective IAQ solutions start with comprehensive testing to identify specific issues like high particles, volatile organic compounds (VOCs), or excessive carbon dioxide levels. Rather than relying on "magic bullet" products, Brynn advocates for a holistic approach that prioritizes ventilation strategies, source control, and proper filtration. He particularly stresses the importance of the "V" in HVAC, ventilation, which he believes is often overlooked in favor of flashier solutions. His company's protocol of testing on every customer visit, from first encounters to maintenance calls, has created a culture where technicians become comfortable discussing IAQ solutions based on actual data rather than assumptions. The discussion transitions into ethical sales practices, a topic that resonates strongly in an industry where pressure to sell can sometimes conflict with customer needs. Brynn defines unethical sales as pressuring customers into products that won't benefit them or failing to provide complete information about benefits and consequences. His approach centers on thorough customer surveys to understand actual problems and budget constraints, followed by tying specific solutions to identified issues. This methodology puts the customer in control of decisions while positioning the contractor as a trusted advisor rather than a high-pressure salesperson. Brynn argues that price alone doesn't determine ethics - rather, it's the intent behind recommendations and the transparency of communication that matters most. The final segment focuses on workforce development, an area where Brynn has found significant success. His company's registered apprenticeship program, developed through the Department of Labor, has become a competitive advantage in attracting talent while providing structured, in-house training. The program requires minimal cost beyond commitment to ethical treatment of apprentices and systematic tracking of their progress. Brynn's transition from contractor to educator demonstrates the growing need for comprehensive training programs that go beyond basic technical skills to include building science, customer service, and ethical business practices. His ongoing weekly training sessions focus on field trends and callback prevention, contributing to an impressive callback rate of less than 0.5%. Topics Covered Indoor Air Quality Testing and Assessment Using monitors like Air Advice for comprehensive IAQ evaluation Implementing testing protocols on every customer interaction Moving beyond product-focused solutions to holistic approaches Ventilation Strategies and Building Science The importance of mechanical ventilation and ERV systems Understanding the relationship between building envelope leakage and humidity issues Source control as the foundation of effective IAQ management Ethical Sales Practices Defining unethical sales and pressure tactics Customer survey techniques and solution-tying methodologies The concept of fiduciary duty in HVAC contracting Equipment Sizing and System Design The impact of oversized equipment on IAQ and comfort Proper load calculations and duct system design Static pressure testing and airflow optimization Workforce Development and Training Implementing registered apprenticeship programs Weekly training sessions focused on field trends and callback prevention Transitioning from contractor to educator and industry trainer Building Envelope and Duct System Integrity Air sealing strategies for improved humidity control The relationship between leaky envelopes and indoor air quality Duct modifications and system upgrades Customer Education and Professional Positioning Using testing data to support recommendations Overcoming price objections through professional credibility Building long-term customer relationships through transparency   Learn more about Brynn's work at hvactrain.com. You can also read his article in Forbes at https://www.forbes.com/sites/brynncooksey/2025/02/19/rescuing-children-from-traditional-post-k-12-school-paths/. Learn more about the GRIT Foundation at https://www.thegritfoundation.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 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

In this short podcast episode, Bryan talks about crankcase heaters, including their different types, what they do, and when we need to use them. Crankcase heaters usually come in belly band varieties, but some can be inserted into the sump of the compressor. As their name suggests, crankcase heaters heat the crankcase when the compressor is off. They prevent flooded starts since the heat keeps refrigerant from condensing to a liquid in the compressor when the system isn't running. Long off times, long line sets, and cold temperatures all increase a system's risk of flooded starts. Hard shutoff TXVs, liquid line solenoid valves, and crankcase heaters are all ways to reduce these risks; the valves hold liquid refrigerant back, and crankcase heaters merely prevent refrigerant from condensing. Crankcase heaters have to be wired to the line side of the contactor or starter. They're often wired around one of the contacts (with a single-pole contactor). When the contact opens, there is a circuit from one leg, through the crankcase heater and compressor windings, to the other leg. This method does NOT use the compressor winding itself as a crankcase heater. When you use a crankcase heater on a compressor with a seam, you want the part of the heater that does the tensioning near the seam. Crankcase heaters should be installed at the base of the compressor, and you'll usually use OEM crankcase heaters.   "Crankcase Heaters and Single-Pole Contactors" tech tip: https://www.hvacrschool.com/crankcase-heaters-and-single-pole-contactors/  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

In this episode of the HVAC School podcast, Bryan welcomes back Jim to discuss the groundbreaking SureSwitch contactor technology from Copeland. This isn't just another incremental improvement - it's a complete reimagining of how contactors should work in modern HVAC systems. Jim brings his expertise and even demonstrates the technology with a special cutaway camera setup, giving listeners and viewers an inside look at this innovative solution. The conversation begins with the evolution of contactors in the HVAC industry, explaining how manufacturers moved backward from heavy-duty two-pole contactors to lighter, more cost-effective one-and-a-half pole designs. While this cost reduction made sense for manufacturers, it often left technicians dealing with more frequent failures and replacements. The SureSwitch represents a leap forward, combining the reliability of traditional heavy-duty contactors with modern electronic intelligence and enhanced protection features. One of the most compelling aspects of the SureSwitch is its multi-voltage coil capability, supporting 24V, 110V, and 240V applications with a single unit. This flexibility dramatically reduces inventory requirements for contractors and service companies, allowing one contactor to handle residential HVAC, refrigeration cases, ice machines, and pool heaters. The universal application makes it particularly valuable for smaller businesses that need to stock fewer SKUs while maintaining the ability to handle diverse applications. The technical innovation behind the SureSwitch's longevity is fascinating. Using an optical sensor (described as a "little eye" in the sealed chamber), the contactor monitors for electrical arcing during contact opening and closing. The built-in microprocessor analyzes the 60Hz AC sine wave and times the contact operation to occur at the zero-crossing point, eliminating destructive arcing. This "no-arc zone" operation, combined with latching contacts that prevent chatter during brownout conditions, results in contacts that remain clean and functional even after a million cycles - five times longer than traditional contactors. Key Topics Covered ·        Contactor Evolution and Industry Innovation o   Historical perspective on contactor design changes from heavy-duty to cost-optimized o   Why the HVAC industry needed to innovate forward rather than continue cost-cutting ·        Multi-Voltage Flexibility o   Single contactor handles 24V, 110V, and 240V coil applications o   Reduces inventory requirements and simplifies contractor operations o   Applications include residential HVAC, refrigeration, ice machines, and pool heaters ·        Arc-Free Contact Technology o   Optical sensor monitoring system for detecting electrical arcing o   Microprocessor-controlled timing to operate at AC sine wave zero-crossing o   Five times longer contact life compared to traditional contactors ·        Chatter Elimination and Latching Mechanism o   Internal power supply eliminates dependency on weak control voltage o   Magnetic latching system prevents contact bouncing during brownout conditions o   Protection against undersized control wiring and long wire runs ·        Sealed Contact Chamber Design o   100% sealed contact chamber prevents insect and debris contamination o   Eliminates common failure modes from ants, earwigs, and lizards o   Reduces need for pest control interventions ·        Built-in Compressor Protection Features o   Brownout protection with automatic voltage monitoring (184V threshold) o   Random start delay (0-90 seconds) for multiple unit installations o   Short cycle timer protection working independently of thermostat timers ·        Installation and Compatibility Considerations o   Compatible mounting holes with standard contactors o   Proper crankcase heater wiring configurations o   Training considerations for technicians adapting to new terminal layout ·        Warranty and Business Applications o   10-year warranty vs. standard 1-year contactor warranties o   Good-better-best selling scenarios for contractor businesses o   Applications in high-end residential and commercial installations   Learn more at the SureSwitch at http://www.hvacrschool.com/SureSwitch.  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 6th 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

In this short podcast episode, Bryan goes through the process of testing and replacing a run capacitor.  Run capacitors provide continuous phase-shifted current to the start winding, allowing the motor to run in the right direction and with the appropriate amount of torque. These capacitors are needed in most of the single-phase PSC motors we work with. Run capacitors are in the circuit all the time and are connected in series with the start winding (compared to start capacitors, which need to be taken out of the circuit after startup). They don't actually "boost" voltage. The bigger the capacitor, the more current can move in and out of the start winding. Run capacitors are made of foil and oil (and the manufacturing quality usually correlates to the capacitor's lifespan), and they usually fail due to overvoltage or overheating. Capacitors may also be replaced with one of a higher voltage rating but not a lower one. Before you test a capacitor, perform a visual inspection. Bloated tops and oil leakage are signs of failure. You'll also want to measure the microfarads and make sure it's within range. An under load test occurs while the system is running (and should NOT be done on blower capacitors for safety reasons). Bench testing happens while the system is off and the capacitor is disconnected and discharged. We have calculators for testing on our app. To test under load, measure the amperage on the start wire and multiply it by 2652. Then, divide that number by the voltage to find the capacitance in microfarads. If the capacitance is over 10% low, replace the capacitor. When replacing a capacitor, make sure the system is off, the capacitor is discharged, and that you tighten the strap and wire it up correctly. It's also a good idea to bench test the new capacitor.   "Capacitor Testing and Replacement Procedure" tech tip: https://www.hvacrschool.com/capacitor-testing-and-replacement-procedure/  "What Is Up With Blower Amps & Watts w/ Steve Rogers" podcast: https://www.hvacrschool.com/podcasts/what-is-up-with-blower-amps-watts-w-steve-rogers/  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

In this comprehensive episode of the HVAC podcast, Bryan hosts an in-depth discussion about dehumidification technologies with two industry experts: David Schurk, National Sales Manager for Innovative Air Technologies, and Nikki Krueger from Santa Fe Products. The conversation explores the fundamental differences between compression refrigeration dehumidification and solid desiccant systems, providing valuable insights for HVAC professionals dealing with moisture control challenges. David Schurk brings 44 years of industry experience and serves as an ASHRAE Life Member and Distinguished Lecturer, teaching humidity control professional development courses. His expertise focuses on solid desiccant dehumidification systems for industrial and heavy commercial applications. Nikki represents Santa Fe Products, pioneers of whole-house ventilating dehumidification technology since the mid-1990s, and discusses the growing residential and light commercial market demands driven by tighter building construction and stricter energy efficiency requirements. The discussion delves into the critical importance of understanding dewpoint versus relative humidity measurements, a fundamental concept that often confuses technicians in the field. The experts explain how the dew point remains consistent throughout a space while relative humidity can vary dramatically based on temperature differences between rooms, floors, and ceilings. This understanding is crucial for proper system design, troubleshooting, and customer education, especially as homeowners become increasingly aware of indoor air quality concerns. The conversation also addresses the intersection of building science and dehumidification technology, emphasizing that proper moisture control requires both well-designed building envelopes and appropriate mechanical systems. From residential applications dealing with tighter construction and mechanical ventilation requirements to industrial processes like lithium battery manufacturing requiring extremely low humidity levels, the experts highlight how different technologies serve specific market segments while sometimes overlapping in commercial applications. Key Topics Covered Fundamentals of moisture control  Compression refrigeration dehumidification Solid desiccant technology  Market applications and demand drivers Building envelope importance  Measurement and troubleshooting  Water activity levels and mold prevention Technology boundaries  Energy considerations Installation challenges   Learn more about Santa Fe's products at https://www.santa-fe-products.com/, and learn more about David's work at https://www.dehumidifiers.com/. Both David Schurk and Nikki Krueger are active on LinkedIn, too.   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 6th 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

In this short podcast episode, Bryan talks about learning styles and gives some tips for "learning better" and getting more out of continuing education opportunities. The first step to getting more out of educational opportunities is to know your learning style. There are three main styles: visual, kinesthetic (hands-on), and auditory. Most tradespeople will probably fall into the kinesthetic category, but not everybody is; you need to figure out if you're most comfortable working with your hands, listening to podcasts, watching videos, or reading. It's also a good idea to try the practical knowledge first and then study the theory. Most people can learn via all of these media, though, and preferences in learning styles aren't excuses not to seek knowledge via the other pathways. Some people also do better with different instructional styles. Instructors can be more or less structured and outgoing, and you may have a preference. Find instructors who explain concepts and conduct their classes or seminars in ways that you understand best. Teaching is also a great way to get a better understanding of a concept, as is incorporating hands-on opportunities and quizzes when you read, watch videos, or listen to podcasts. When you can teach and be taught in non-judgmental environments, you can get a lot more out of the learning experience. Comprehension comes before retention, so memorization is usually not going to be too helpful for HVAC education. Understanding should be the main focus, not memorizing facts or test answers, and that includes challenging your assumptions and finding hard problems to solve. You can also discover HVAC/R concepts in unexpected places, including scientific or lifestyle YouTube channels and podcasts.   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 6th 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