Hvac School - For Techs, By Techs

In this short podcast, Bryan talks about evaporator coil placement based on a question submitted by a listener, John. Evap coil placement differs in furnace applications versus air handlers. When we use air conditioners with furnaces, we usually put evaporator coils on the positive side to protect the heat exchanger from rusting out during the summer (due to condensation and the chemical reactions that can occur with the metal heat exchanger). However, when it comes to air handlers, they're usually on the negative side. The coil is usually on the negative side of a fan coil or air handler because it keeps the blower motor cooler (though that doesn't make a huge difference in terms of performance).  The HVAC system will lose fewer BTUs to leakage when the coil is on the negative side, which is better for energy efficiency; those BTUs can reach the conditioned space rather than the closet, garage, or wherever it is stored. Pulling air over the evaporator coil on the negative side, however, could potentially lea

In this episode of the HVAC School Podcast, Bryan interviews Zachary Ortwine, a duct cleaning professional who provides insights into ethical duct cleaning practices. The conversation delves deep into the complexities of cleaning different types of ductwork, the importance of proper assessment, and the potential challenges in maintaining indoor air quality. Zach emphasizes the critical role of thorough inspection and honest communication with clients. He explains that not all duct systems are equally cleanable, and professionals must carefully assess factors like duct material, contaminant type, and cleaning feasibility. Metal ducts can be cleaned more aggressively, while fiberglass ducts require a more delicate approach. The discussion highlights the importance of understanding the underlying issues that contribute to indoor air quality problems, such as system design, maintenance, and home living conditions. The podcast explores the evolution of duct cleaning technologies and safety considerations. Zach sha

In this short podcast episode, Zach joins Bryan to answer a common duct maintenance question: Should I fog or sanitize my ducts? The National Air Duct Cleaners Association (NADCA) outlines the uses of chemical products. Adding chemicals is usually a last resort in flex or sheet metal (externally wrapped) duct systems; they should NOT be used on ducts with internal liners or are made of duct board or any other material with porous surfaces.  Fog is typically applied while a vacuum is running at the opposite end of the duct. It liquefies on surfaces, and a lot of contractors don't go in and dry off the duct surfaces. It's difficult to coat the entire interior of a duct system with the chemical to make it as effective as possible, and the residue creates a moist, sticky film that actually encourages microbial growth in the ductwork. On top of that, some people may be sensitive to the chemicals.  In many cases, replacing ductwork that has been confirmed to have microbial growth is more reliable. Chemical duct san

Bryan and Craig Migliaccio (AC Service Tech)dive deep into the complexities of managing condensate drainage in high-efficiency (90%+) gas furnaces. The conversation begins with a clear explanation of why these furnaces produce condensate in the first place - they have two heat exchangers that extract so much heat from the combustion gases that water vapor condenses out. This condensate is acidic (pH 3-5) and requires special consideration for drainage and disposal. The discussion explores various challenges contractors face when installing these systems, particularly in cold climates where freezing is a concern. Craig shares practical solutions from his experience in New Jersey, including using larger diameter pipes for exterior drainage and creating air gaps to prevent complete freezing. They address the ongoing debate about whether to combine AC condensate lines with furnace condensate lines, noting that while it's technically possible, there are potential risks and code considerations to keep in mind. A si

In this unique episode of the HVAC School podcast, Bryan interviews Donovan Ryckis, CEO of Ethos Benefits, diving deep into the complex world of healthcare financing and employee benefits. Ryckis shares his journey from financial advising to becoming a healthcare benefits consultant, driven by a mission to expose and transform the inherently problematic healthcare system. The conversation reveals the stark inefficiencies in traditional healthcare models, where insurance companies and healthcare providers often prioritize profit over patient care. Ryckis explains how most employers have been led to believe they cannot control healthcare costs, accepting annual increases as inevitable. By applying a fiduciary approach—similar to financial advising—Ethos Benefits helps companies like Kalos dramatically reduce healthcare expenses while maintaining or improving employee care. A key highlight of the discussion is the innovative strategies Ethos implements, such as negotiating directly with healthcare providers, exp

Chris Hughes and Steve Rogers from The Energy Conservatory discuss TEC's TrueFlow technology and its crucial role in predicting airflow issues in the sales process, particularly for heat pump retrofits. They explain how the TrueFlow app helps contractors accurately measure both static pressure and airflow in existing systems, enabling them to predict whether proposed equipment changes will work effectively. This is especially vital when considering the growing trend of replacing gas furnaces with heat pumps, as the airflow requirements can differ significantly. The conversation delves into a detailed example of replacing an 80% efficient 48,000 BTU furnace with a heat pump. They demonstrate how the airflow requirement would nearly double from 652 CFM to 1,200 CFM, potentially causing the static pressure to quadruple due to Fan Law 2 principles. This dramatic increase could lead to significant performance issues if not properly addressed during the system design phase. The experts emphasize that using TrueFlow

In this short podcast episode, Bryan and Mike from DITEK talk about what to do in tricky electrical scenarios, such as when the MCA is 27 and you have a 50A breaker. When you size an HVAC system for compatibility with voltage monitors, like the DITEK Kool Guard, you need to pay attention to the MCA (minimum circuit ampacity), which should not be confused with MOCP (maximum overcurrent protection or breaker size). As long as the MCA is 40 amps or lower, you can attach the HVAC condenser to the Kool Guard. The KG2 also accepts wire sizes up to 6 AWG. The Kool Guard is NOT a source of overcurrent protection; it is a voltage monitor rated for carrying current, which means ratings will be in MCA, not MOCP. MOCP is designed to deal with high starting amps and lets users know the maximum allowable current for a circuit so that it can trip properly when that current is exceeded. According to Section 440 of the National Electrical Code (NEC), motors with internal overload protection allow for a difference between the

Bryan discusses surge protection devices (SPDs) with Mike from DITEK, focusing on practical applications for HVAC contractors and how to provide value to clients. Mike emphasizes that surge protection is essential for modern HVAC systems, particularly given that they are typically the most expensive appliance in a home and increasingly rely on sophisticated electronic components like variable-speed compressors and inverter boards. The conversation delves into installation best practices, with a detailed discussion of proper wiring techniques for SPDs. Mike explains that surge protectors should be installed in parallel with the circuit, typically at the disconnect, and addresses common concerns about double-tapping lugs and ground connections. He emphasizes the importance of keeping wire lengths as short as possible and provides guidance for installations both with dedicated disconnects and panel-direct connections. A significant portion of the episode focuses on DITEK's Kool Guard (KG2) product, which represe

In this short episode, Bryan clears up the confusion behind pumping vs. compression. Pumping is usually associated with liquid. Liquid, like vapor, is a fluid, but it's a lot denser and is essentially incompressible because the molecules are close together. Liquid volume varies based on temperature and density, but we can't squish the molecules together. That's why compressors with very little axial and radial compliance fail when flooded; they can't compress the liquid. A circulator pump in a hydronic system is an example of a pump that pushes liquid along, but the pressure difference across the pump is minimal compared to that of a compressor; the same is true of liquid vs. vapor CO2.  However, vapor molecules are far apart and can be squished together to take up a smaller volume. That's why vapor can go through compressors, which take a fluid of one volume and apply pressure to shrink it to a smaller volume, raising the temperature in the process. Pneumatics, as opposed to hydraulics, utilize compression t

Trevor Matthews returns to the HVAC School Podcast to discuss building tech confidence and personal growth in the HVAC and refrigeration industry. The conversation explores the transformative power of self-investment, continuous learning, and maintaining a positive mindset. Trevor shares his personal journey from a hesitant technician to a successful business owner, highlighting the importance of pushing beyond comfort zones and embracing continuous improvement. Some fundamental mindset shifts are necessary for professional development. Trevor candidly discusses his early career struggles, including his initial fear of public speaking and technical challenges. He emphasizes that confidence isn't something that happens overnight but is built through consistent effort, studying, and maintaining a willingness to learn. The key to the growth mindset is to focus on personal progress instead of comparing your achievements to those of others, and it's a perspective that can dramatically impact professional and perso

In this short podcast episode, Bryan talks about the CPS Molecular Transformator and what it does. The Molecular Transformator is a version of a tube-in-shell heat exchanger, which is a method of exchanging heat from one fluid medium to another fluid medium. Tubes containing a fluid pass through a shell containing water or glycol, and there is a heat exchange between that secondary fluid and the fluid being circulated in the tubes. In a Molecular Transformator, the fluid being circulated is recovered refrigerant, and the secondary fluid is water (in a bucket), which absorbs heat from the refrigerant and cools it down to make sure that the refrigerant enters the recovery tank as a liquid. Refrigerant recovery machines have condensers inside of them, but they are quite small and don't hold a lot of refrigerant by design; many recovery machines use microchannel coils. A lot of the time, the refrigerant leaving a recovery machine is a liquid-vapor mix and too high-temperature; a lot of people run a hose over the

In this enlightening episode, we sit down with Mike, a 20-year veteran from DITEK, a leading American manufacturer of surge protection devices based in Largo, Florida. The conversation begins with a brief discussion about recent hurricane impacts in the Tampa Bay area, where DITEK maintains its 65,000-square-foot manufacturing facility. Mike shares how the company, despite facing challenging weather conditions, continued its operations and maintained its commitment to American manufacturing. The bulk of the discussion centers around surge protection technology and its critical importance in protecting HVAC systems and other electronic equipment. Mike provides an excellent analogy, comparing surge protectors to pressure relief valves for electrical systems. He explains how Metal Oxide Varistors (MOVs) work as semiconductors that create low impedance paths to ground when voltage exceeds certain thresholds. The conversation delves into the evolution of MOV technology, particularly the development of thermally pr

Bryan answers a listener-submitted question: "Am I toxic for caring?" He gives advice on how to maintain professional relationships while still maintaining very high standards of quality for your own work. Having high standards is great, but it can be frustrating when you perceive coworkers as having lower standards than you. A poor-quality end product is fairly objective, but other ways of judging coworkers' standards are a lot more subjective and may vary by culture, and we end up judging the person rather than the work. While we should care about the objective outcomes of a job, we want to challenge ourselves when we start comparing others' work to our own unfavorably. Judging others' work isn't inherently bad or "toxic," but it has to be controlled and done in service of something greater. When we confront others or judge their work, we need to make sure it comes from a place of professional pride (rather than personal pride) and personal humility. As tradespeople, we don't always do the best work, either

Ruchir Shah joins the podcast to share his journey into HVAC education technology and the founding of SkillCat, a comprehensive training platform for skilled trades. As a five-time entrepreneur in educational technology, Ruchir's path to HVAC was influenced by his earlier work studying the BP oil spill and developing training solutions for oil and gas workers. When COVID-19 hit and many skilled workers found themselves displaced, he recognized a broader pattern of declining income for blue-collar workers over the past 50 years, which led to the creation of SkillCat. The discussion delves into SkillCat's innovative approach to EPA 608 certification, making it more accessible and affordable at just $10 per month. Their platform uses phone-based testing with built-in security measures, achieving a 97-98% pass rate through comprehensive training. This system addresses traditional barriers like high costs, scheduling difficulties, and low pass rates that have historically made it challenging for people to enter

In this short Q&A podcast, Bryan answers a listener-submitted question about apps for doing proper loads. Fred specifically asks about apps or charts that can help an HVAC contractor determine the insulation value of a home without assuming numbers or drilling into walls during load calculations. Load calculations account for all the ways that BTUs can enter or leave a home: conduction, convection, and radiation. Insulation prevents heat transfer via conduction, so it's important to the load calculation process. High-end HVAC design software like Wrightsoft and Kwik Model 3D will have these features built into them (based on the age and location of the home). ASHRAE's handbook also has tables and data with R-values and U-factors to help you out with Manual J load calculations. RED Calc is an app that allows you to calculate a wall's R-value with measurements, including surface and air temperatures indoors and outdoors. This RED Calc software is available through the U.S. Department of Energy, as is RESche

Bryan sits down with Jim Bergmann at the NCI Summit in Asheville, North Carolina, to discuss the latest developments in HVAC technology, training, and industry trends.  The discussion delves into the evolution of MeasureQuick 3.0, highlighting the shift back to a more technician-centric approach. Jim explains how they've redesigned the software to put gauges front and center and implemented an AI-driven system to guide technicians through the process step-by-step. This renewed focus on the end-user experience aims to make the product more valuable for technicians and, in turn, more likely to be adopted as part of standard operating procedures in HVAC companies. Jim and Bryan also explore the importance of understanding HVAC history and fundamentals. They discuss how revisiting old engineering books can provide valuable insights into the core principles of the industry, often explained in more accessible terms than modern textbooks. This approach to learning, combining practical experience with theoretical kno

In this short podcast episode, Bryan answers a listener-submitted question about an HVAC system that won't dehumidify. This question was submitted by a homeowner with a Carrier heat pump with an attic air handler that cools but won't dehumidify on the hottest days of summer. One of the past companies that serviced the system added charge, but the problem wasn't resolved. This case doesn't seem to be a sizing issue, as the insufficient dehumidification is happening on the hottest days. Normally, sizing issues happen during the edge seasons when temperatures aren't as high as in the summer, but the dew points are still high.  Bryan's first recommendation is to use measureQuick to evaluate the delivered capacity and determine the sensible heat ratio (SHR) by comparing sensible BTUs to latent BTUs. High SHRs are associated with less effective dehumidification and more effective sensible BTU removal. Then, we have to determine that airflow is properly dialed in. Typically, lower fan speeds are associated with bett

Bryan Orr and Steve Rogers dive deep into measuring power consumption in HVAC blower motors, particularly focusing on the differences between PSC (Permanent Split Capacitor) and ECM (Electronically Commutated Motor) technologies. The discussion stems from a question raised at an educators' conference about the accuracy of clamp-on meters in measuring blower motor watt draw, as specified in the ACCA Standard 310. Steve shares insights from extensive testing conducted with different types of motors and power meters. The tests compared PSC motors with constant torque and constant airflow ECM motors across various static pressure conditions. One key finding was that two out of three field-available clamp-on meters tested were capable of accurately measuring true power at levels expected in residential blower motors. However, one meter showed significant inaccuracy at low power levels, highlighting the importance of carefully reviewing meter specifications before use. The conversation delves into the concept of po

In this short Q&A podcast, Bryan answers a listener-submitted question about sizing heat pumps for heat load in heating mode, something that we haven't talked much about in the past due to the greater need for cooling in our market. In most cases across the country, a heat pump's heating loads will be greater than the cooling loads. There is a greater swing between the desired temperature and the actual temperature in heating mode than in cooling mode (in terms of sensible BTUs). We don't want to oversize for cooling because of its lower efficiency, comfort, and humidity control due to the shorter runtimes. (However, oversizing for cooling loads is far less of an issue in arid climates.) We don't want to oversize the heat pump to meet the heating load when we'll far exceed the cooling load. However, that's not much of a concern for the opposite scenario in which we oversize for heating to meet the cooling load. We can add auxiliary heat, such as electrical heat or natural gas in dual fuel setups, to help

This episode of the HVAC School podcast dives deep into the often-overlooked but critical topic of water issues in HVAC systems. Bryan and Bert discuss the various causes of water leaks and condensation problems, and they explain how to prevent them. They emphasize that water damage is not an inevitable part of HVAC systems and that with proper attention to detail and understanding of the underlying causes, most issues can be prevented. "Spidey Sense" refers to a heightened situational awareness that allows technicians to anticipate and prevent water-related problems. Common water-related problems include drain backups, improper trap depth, and freezing issues, and Bryan and Bert provide practical advice on how to identify and address these problems. The conversation also covers the importance of proper installation techniques, including the correct placement of float switches, insulation of copper lines, and the pitching of secondary drain pans. Bryan and Bert highlight the need for technicians to think crit