HVAC School - For Techs, By Techs

Bryan explains how parents and educators can succeed at giving kids the tools for any job they want. This podcast was originally a presentation at the 2022 FPEA Florida Homeschool Convention. Jobs, careers, and vocations have changed a lot over the years. Even though those have changed over the years, parents still want their kids' vocations to develop character, foster growth, and bring joy. While kids are young, parents can instill values of grit and diligence; however, parents have to overcome the challenges presented by the instant gratification provided by technology. Interest-guided learning is a double-edged sword, as it allows a child to pursue their interests but can cut them off from the interest of others. Developing the values of kindness and deference can temper the negative effects of interest-guided learning while maintaining the benefits of interest-guided learning. If a child has an interest in something and can pursue that interest on their own by demonstrating autodidactism, they open themself up to a lot of vocational options. Nowadays, it's a lot more common for people to hold many different jobs or vocations over their lifetime. Encouraging a child to learn different skills allows them to explore non-linear career paths more easily than children who don't learn useful skills. When teaching children, developing mental models and an appreciation for learning is another key to success across vocations. Bryan also talks about: Vocation vs. avocation Grit vs. talent in the pursuit of success Modeling and practicing gratefulness Transferable skills Feeling "stuck" in a vocation Visualizing average molecular velocity Learning about humidity and electrical movement Striking a balance between joy, service, and passion Expectations vs. standards Pursuing college, business ownership, and other career opportunities If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE.

In this short podcast episode, Bryan talks about ERV and HRV technologies, including their appropriate applications and limitations. HRVs are heat recovery ventilators (not to be confused with heat recovery units or HRUs), and ERVs are energy recovery ventilators. The main difference between these two lies in the type of heat they move; HRVs only move sensible BTUs, whereas ERVs move sensible and latent BTUs. As you bring air in from outside, you're discharging roughly the same amount of air (though modern technologies allow you to manipulate the pressure a bit more). The goal of the HRV or ERV is to recover some energy from the air exiting the structure and incorporate it into the incoming airstream. The airstreams cross over each other, and there is heat transfer but not air mixing. (ERVs also allow for the exchange of moisture.) Two fans drive the direction of energy flow, and a mesh or a porous desiccant medium facilitates the interaction between the airstreams. You will get some energy savings with an HRV or ERV, but savings are dictated by the amount of air moved and the temperature differential between the airstreams. In general, you will see HRVs up north (in low-humidity markets) and ERVs down south (in higher latent-heat markets). However, even ERVs aren't very effective in conditions with low energy transfer and high moisture UNLESS they're used with a ventilating dehumidifier. Bringing in fresh air is good for indoor health and safety, as it helps dilute the presence of VOCs, viruses, and harmful gases. HRVs and ERVs help us manage the air we bring in. Bryan also covers: Integrating ERVs with bathroom ventilation Safety considerations to consider for outdoor air Positive pressurization Demand ventilation with CO2 sensors Learning about ASHRAE 62.2 If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE.

Rajan Rajendran and Jennifer Butsch from Emerson join the podcast to discuss the Helix and some refrigerant changes that are coming. Jennifer is the Director of Regulatory Affairs, and Rajan is the Global Vice President for Environmental Sustainability and former director of the Emerson Helix. Lately, there have been more environmental efforts to reduce greenhouse gas emissions, and plenty of large corporations have "net zero" initiatives. Sustainability requires a holistic, systemic approach in our industry; the Helix Innovation Center conducts the research needed for us to handle these sustainability initiatives as effectively and safely as possible. However, the sustainability initiatives frustrate a lot of technicians. There will likely be multiple refrigerant transitions as our industry progresses. Education and knowledge provided by manufacturers and HVAC organizations will be the key to smooth transitions. Many of the replacement refrigerants, including R-32 and R-454B, are A2Ls. These mildly flammable refrigerants have different handling, transportation, and charging procedures than what we're used to. However, we are unlikely to see changes in oils; POE and PVE oil will likely remain dominant in the market. Eventually, we may see more GWP changes. We would also be prudent to focus on preventing and rectifying equipment leaks. Proper maintenance will help us navigate current and possible future changes. Rajan, Jennifer, and Bryan also discuss: The AIM Act and HFC reduction in 2024 GWP-limit petitions in HVAC vs. refrigeration Refrigerants that manufacturers are embracing Refrigerant testing processes Natural refrigerants The weight of refrigerants vs. the weight of air Evaporator coil manufacturing and leakage Built-in leak detection Refrigerant pricing To learn more about these coming refrigerant changes, check out the AHRI Safe Refrigerant Transition Task Force's resources HERE or Emerson's E360 Platform HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE.

In this short podcast episode, Bryan talks about pilot controls. He talks about the old-school ignition systems on gas appliances and some similar pilot functions on residential A/C units and heat pumps. When we think about a pilot light on a gas appliance, we can think of it as a small standing flame that sits there ready to ignite the burner whenever gas is flowing. Pilot lights were necessary for old-school gas furnaces, and many of those pilot lights worked with a thermocouple. In many older furnaces, pilots also prevent excessive carbon monoxide from unspent gas. In other words, the pilot is not the main burner; it merely sets up the main burner. On a typical A/C system, the 24v power is similar to a pilot on a gas appliance; the 24v "pilot" control energizes the system and has a small amount of voltage (compared to the high voltage needed for all of the components to work). The reversing valve on heat pumps also has a pilot valve; the 24v signal activates the pilot valve with the solenoid, which redirects system pressure to allow discharge gas to slide the valve. That's also why you can't shift the operating mode when the system is off. Solenoid valves in general tend to have pilot functions; they rely on a refrigerant pressure differential that results from 24v electrical signals, not the signal itself. In short, we don't rely on the pilot light or the 24v electrical signal to power the entire equipment. Pilot controls merely help the equipment get started; they have less load on them and trigger or control parts and processes that are more complicated. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE.

Bryan and Robert Orr continue their discussion about ethics by talking about what it means to have grit and discipline in business. They talk about what those characteristics look like in business and in life, and they mention some good books. Grit is a trait that can contribute to an ethical way of life; showing grit means that you follow through with a project until you get the results you want. Both physical and emotional grit are strengths, and those things tend to be more important than talent in our field. Compared to discipline, grit is a lot more closely intertwined with a person's emotional condition. When we encounter overwhelming negative emotions, grit is the quality that allows us to power through the current state of affairs. Discipline and grit are both based on commitment and resolve, but discipline deals more with actions rather than feelings. Discipline is more about habits, balance, and wisdom. A belief system or set of guidance is what drives discipline. Discipline can also be repetitious and boring, but it can take you farther than raw talent if you dedicate yourself to your belief system, sources of guidance, and goals. Developing discipline requires us to establish habits and sequence those habits. Good leaders and parents are the ones who establish those habits for employees or children. However, something to keep in mind is that both grit and discipline can amplify a person's bad characteristics. Robert and Bryan also discuss: Grit vs. talent (Angela Duckworth) Does grit count as an ethic? Discipline and delaying gratification Developing grit over time "Real" vs. "true" emotions and thoughts The downfalls of raw talent Thinking about obstacles in a healthy way If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE.

Bryan and Robert Orr talk about ethics and what it means to have integrity when running a family business. Robert is a lifelong tradesman who is a licensed construction contractor, and he has overseen the construction side of Kalos for many years. Robert initially started off at the Air Force Academy and realized that he didn't feel that the military was right for him. While in Florida, Robert fell into the trades and learned both hard skills and ethics in the process. He started his own house-wiring business at age 21. Later, he went into home inspection and eventually started a business with his son (Bryan) and his brother-in-law (Keith) Kalos was co-founded by Bryan, Robert, and Keith, all of whom were tradesmen. Even when naming their business, they wanted to focus on ideals that extend beyond them and their individual legacies. They settled on the name "Kalos," which is the Greek word for "integrity." Having integrity in business is a lot more than just following rules and "having principles." Real integrity is authentic and honest; you're transparent about who you are and deliver on the promises you make. Integrity and customer service are NOT the same thing, but you tend to yield higher customer satisfaction if integrity is at the forefront of your business. Evaluating yourself is also a component of integrity: reflecting on your desires, confronting greed, caring for employees, and choosing to do the right thing. In many small businesses that haven't fully found their stride, integrity can be compromised by fear. Robert and Bryan also discuss: Christianity in business Integrity as it relates to pricing expectations What it means to be savvy Taking responsibility If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE.

In this short podcast, Bryan talks about distributors and external equalizers and why we need to use them together. When older Carrier heat pumps (with pistons) would run in heat mode, the metering device would be outside. In those cases, the port on the liquid line would be on the opposite side of the metering device. So, you wouldn't actually be measuring the liquid line pressure (high-side) if you measured it at that port while the system runs in heat mode. However, that pressure would be higher than the common suction pressure. That's because distributors and distributor tubes also have a pressure drop associated with them AFTER the metering device. Nowadays, TXV systems have external equalizers, which create an equalizing force inside the valve. The bulb pressure forces the valve open, and the equalizer pushes against that pressure to create a closing force. An internal equalizer would work fine on a system without a distributor or distributor tubes; however, those systems are few and far between. We need an external equalizer on systems with distributors because the pressure at the end of the evaporator coil is significantly lower than the pressure picked up by the valve. Without closing force, the TXV would theoretically force itself all the way open and flood the evaporator coil. External equalizers can get clogged, which results in a pressure buildup during the off cycle and forces the valve closed. They can sometimes get clogged when used on a Schrader port without a Schrader depressor inside the equalizer. Some people attempt to fabricate distributors in the field. It works in some cases, but in many cases, it's best to use an engineered distributor for the best performance and efficiency. The distributors are individually designed to create an individual pressure drop. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE.

In this short podcast episode, Bryan talks even more about sine waves and center-tapped transformers. Power is generated at the power plant when an energy source (such as steam) is used to drive a drive shaft. The resulting current can be mapped as sine waves, which actually represent points on a circle; there is a rotational magnetic field around stationary conductors, and the sine waves allow us to envision the positive and negative alternations as the rotation happens. Center-tapped transformers use "neutral" as a reference point. The secondary winding on a center-tapped transformer may have 240v power, but the center tap splits that 240v power into two legs of 120v power. There are two sine waves completely out of phase with each other, so we get 240v from peak to peak. Both sine waves cross at neutral. Even though the split-phase power consists of two separate sine waves, an oscilloscope would interpret the voltage as a single up-and-down wave with a higher peak and a lower valley. Center-tapped transformers do not necessarily create another phase of power; they merely turn neutral into a reference. If we were to measure that split-phase power as a single 120v sine wave with an oscilloscope, we would have to use neutral as our reference. To measure the separate sine waves for a total of 240v, we would need three probes: a reference at neutral and one reference on each side. Many European countries only use a single sine wave; center-tapped transformers are not commonplace in those countries, and neither is split-phase power. However, the split-phase power in the USA allows for more versatility; we can supply power to 120v appliances where we would otherwise need to use 240v ones. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE.

Bryan describes the tricky concept of power factor and why we should care about it. He also compares power factor to a beer mug to make the topic easier to understand. Power is often represented on a sine wave, which is a curvy line that marks the state of electrical energy at different points on a circle. Power gets stronger and weaker, and it goes above and below the neutral line depending on the excess or deficit of electrons. Unity power factor refers to a power factor of 1, indicating that voltage and amperage are perfectly balanced; there is no lag. However, an inductance (a form of resistance) opposes the current and causes an imbalance between current and voltage. Power loss or quality refers to the difference between the input and output power that results. Apparent power refers to volt-amps, which we'd traditionally consider to be the wattage; however, in an inductive load, the true or real power (wattage) accounts for that power loss and comes from volts x amps x power factor. We can imagine power factor as a mug of beer: apparent power (VA) is the entire mug, the foam is reactive power (wasted), and the beer itself is real power. The power company only charges for the real power, not the reactive power. However, a power factor closer to unity can help prevent motor windings or wires from overheating. To get closer to unity power factor, we need to make sure we have a run capacitor of the correct size. You can measure power factor with a power quality meter. Bryan also covers: Voltage and current Root mean square Inductive reactance Capacitance and how capacitors work Transformer VA ratings If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE.

Bryan lays down some motor speed facts in about 10 minutes in this short podcast episode. We can figure out how quickly a single-phase motor (PSC) will run if we understand how many cycles it will make per second. In the USA, the standard hertz is 60 Hz (60 rotations or magnetic alternations per second). Motors are inductive loads that create an electromagnetic field with a spinning rotor and stationary stator; the amount of poles on the stator determines how quickly the rotor spins (RPM). In the RPM counts, there are some allowances for slip. Slip varies depending on the load, with excessive loads causing more slip. Some multi-tap blowers have additional winding resistance and decreased current (due to the extra taps), which increase the slip. The rated load RPM usually accounts for the RPM at high speed, not medium or low speed with added resistance. On the other hand, variable-speed motors or ECMs are powered by a variable frequency (sometimes a variable frequency drive or VFD). The motor control takes the incoming electrical frequency and converts it into a new frequency (turning AC power to DC and controlling the cycle rate). These motors also tend to be more efficient as a result. The RPM is more variable on these motors with VFDs, whereas we could only manipulate the RPM of single-phase motors by changing the number of poles. When replacing a motor, you can't use a replacement motor with a higher rated RPM than the original motor. The only way to change the RPM is to get a new motor with a different number of poles, increase slip to make it slower or decrease slip to bring it closer to synchronous speed, or adjust the frequency. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE.

Neil Comparetto and John Semmelhack of the Comfort Squad join Bryan to discuss high-quality value design in a high-performance home. They explain how they design HVAC systems (heat pumps) for low-load homes in ways that are affordable, efficient, and comfortable. High-performance, low-load homes need to be energy-efficient AND comfortable, and it can be a challenge to get both. Manual J calculations aren't as common as they probably should be, and it can be difficult to get accurate data about air leakage, power consumption, and radiant gains as well. So, John and Neil try to collect their own data and do aggressive load calculations to avoid the fudge factors that are all too common. The air velocity inside the ducts tends to be lower in these sorts of systems. When you have relatively low airflow in the ductwork of high-performance homes, you don't need as many ducts or for the ductwork to be particularly large. With minimalistic ductwork, supply register placement, face velocity, and throw become very important, especially because those factors are responsible for air mixing. When the duct design conditions are right and the load has been matched, you typically get long runtimes and good air mixing. In many cases, John and Neil use variable-speed motors in their outdoor units that allow for high heating performance. The capacity ranges are wide, allowing the units to run even during exceptionally low-load conditions. They also use flex ducts due to their pre-insulation, noise suppression, and inexpensiveness; they just try to keep it sealed and avoid compressing the ductwork. Neil, John, and Bryan also discuss: Monitoring load conditions with software Design considerations for filter grilles and central returns Room pressurization and airflow testing Transfer grilles The Coanda effect and curved-blade registers Vent sizing Flex duct installation best practices Duct fittings ERVs If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE.

Lacey Dietz with METUS and Scott Arnold with Rycor HVAC join the podcast to talk about how the industry can start putting contractor success first. They talk about Mitsubishi Electric (METUS)'s commitment to contractor success and what that looks like. METUS's contractor program aims to provide training, support, and recognition to create a community of successful contractors. Support comes in the form of marketing, training, tech support, and customer service, and those services are available to contractors who sell and represent Mitsubishi's products. As a contractor who works with Mitsubishi, Scott has been able to specialize the labor in his business and grow his business as one that specializes in installing Mitsubishi systems. Mitsubishi also provided top-quality training and allowed Scott to streamline his training process and get his apprentices feeling confident and ready to go into the field quickly. Adoption rates for Mitsubishi's ductless technology have increased over the past couple of years, especially as people have spent more time in their homes and started re-thinking indoor comfort. Those who are educated about heat pumps also tend to appreciate the technology as well as the mini-split units' small footprints in their homes. The mini-split units' smaller environmental impact than unitary systems is also a plus. Lacey, Scott, and Bryan also discuss: Scott's work with heat pumps in New York Programs that benefit contractors Mitsubishi's products and supply chain management Diamond Contractor program and tiered contractors Mitsubishi's lead generation program and referrals Ductless vs. unitary systems Bringing education into sales Dealing with business growth in a challenging labor market Overcoming objections Learn more about Mitsubishi and its products, visit https://www.mitsubishicomfort.com/, and you can learn how to become a contractor at https://discover.mitsubishicomfort.com/contractors. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE.

Sam Myers with Retrotec talks to Bryan about pressures in the home and why they matter for HVAC solutions at IBS 2022. Technicians focus a lot on ductwork and airflow, but many of them don't focus on how the building envelope impacts HVAC performance. A lot of the HVAC equipment's performance is affected by the push and pull of air caused by leaky areas in the building envelope. If you have a room with too much air and another room with too little, you will have unbalanced pressures. Unbalanced pressures may result in discomfort and latent load issues, especially when unconditioned air is pulled in through the attic. Sealing the envelope well and using dampers as necessary can minimize the comfort issues caused by pressure imbalances in the home. Instead of just using manometers for static and gas pressure, we can also use high-resolution manometers under doors to pick up pressure differences. However, the manometer MUST be high-res to pick up those subtle (but palpable) differences in pressure. A blower door is also a great tool, especially when you use it with a thermal imaging camera; the blower door amplifies the temperature effects that a thermal camera will detect, especially if you also have a good delta T. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE.

This podcast is a class that Bryan taught for BTrained in Birmingham, AL. He covers troubleshooting, installation, and commissioning best practices with a focus on the fundamentals. To be a good troubleshooter, you must be able to find the problem, identify the source of the problem, fix the problem, and optimize performance based on your data, the customer's comments, and your observations. The Five Pillars of diagnosis aren't comprehensive diagnostic or charging criteria, but they can help you charge or diagnose a system. Isolation diagnosis works best for electrical components; you isolate the problem area from the system and see how the system works without the suspected issue. If the system operates normally without the component in question, then we can conclude that our hypothesis about the "problem" part was correct. Wide-narrow-wide troubleshooting is an approach that allows you to inspect the entire system, zero in on the problem, and optimize the entire system. By starting wide, going narrow, and going wide again, you can troubleshoot holistically. Installations take place in several phases: pre-planning, planning, demo, installation, and commissioning. Many people place a lot of emphasis on the demo and installation and neglect the conversations and procedures associated with pre-planning, planning, and commissioning. Bryan also covers: Heuristics and mental shortcuts Evaporation vs. boiling Rules of thumb Head pressure, suction pressure, and compression ratio Energy transfer fundamentals What superheat and subcooling really indicate Restrictions and temperature drop Delta T "Redneck" compressor test Testing circuits Useful measurements and test instrumentation Causes of compressor failure Measuring airflow Low vs. high static pressure Bringing tribal knowledge to building design Ductless systems, ventilating dehumidification, and sensible heat ratio Manual J, attics, and combustion air Radiant barriers and heat transfer Supply relative humidity Dehumidifier configuration and system design Bad envelopes Vented attics Duct upgrades Total effective length and turning vanes Evacuation Learn more about BTrained at https://btrained.net/ or on the BTrained YouTube channel at https://www.youtube.com/channel/UCnlDsWHT68gVwPrYYO5vhrw. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE.

Bryan has a bit of an industry nerd out with Ross Trethewey from "This Old House" and TE2 Engineering at IBS 2022 (the International Builders' Show). Ross's education and career have focused on mechanical engineering, especially with sustainable solutions. In building science, the key mindset is to think of the building as a system. Using that school of thought, Ross has developed building science and HVAC solutions that also consider indoor air quality and ventilation, such as hybrid VRF systems. Many of Ross's solutions take the best aspects of air-source and ground-source heat pumps and apply those to hydronics. Some exciting applications for those types of systems could include simultaneous heating and cooling as well as the integration of domestic hot water. Demand control ventilation has been used for a long time in the commercial world, but its possible use in residential applications is another exciting thing to consider. With proper control devices, DCV would give us the opportunity to control temperature, humidity, VOCs, carbon monoxide, carbon dioxide, and radon. In residential applications, DCV has to be a delicate balancing act, as bringing in too much outdoor air would require us to condition that air. High latent loads also present challenges to some of the ventilation solutions in development. Serviceability is another challenge to DCV usage in residential applications; whenever an innovative system is brought to the market, very few people will know how to fix and maintain those systems. One of the possible solutions is to create instruction manuals and give education similar to what already exists for package units. 3D models and animations also help make complicated systems easier to understand. Ross's presence on "This Old House" marks the third generation of Tretheweys on the show. Ross is excited to talk about building science and HVAC innovations and concepts while on the show. Heat pumps are also getting better, especially due to inverter-driven compressors, enhanced vapor injection, advanced control systems, and ECMs. Heat pumps are safer than gas-fired equipment, and we have made them work well in subzero temperatures (because we're nowhere near absolute zero). If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE.

In this podcast, Bryan goes through the entire process of replacing a compressor step-by-step. This process is what the Kalos team uses to replace a failed compressor and make sure it doesn't fail again. Before replacing a compressor, you must figure out how the compressor failed; grounded conditions often lead to acid, so it's a good idea to test for acid and see if you need to address a burnout. In any case, make sure you have the correct tools for the job (including a compatible replacement compressor). When you arrive at the job site, be sure to confirm the diagnosis and check to see if the unit has a hard start kit. That's also the time to do a visual inspection, checking airflow as well as the filter, blower, and coil cleanliness. Recover and weigh out the refrigerant charge. Unscrew the foot bolts and lift the old compressor out. Then, seal the compressor once it's out. If you're dealing with burnout, clean out or replace the accumulator (you will install/reinstall it shortly). Cut out and replace the existing liquid line drier and install a suction drier in a place where it can be easily removed. When piping in the new compressor, make sure you protect heat-sensitive parts and do a quality brazing job. Install the new capacitor and hard start kit, too, keeping wiring away from places where it may chafe. Test for leaks, evacuate the system, charge the system, and check your five pillars as well as voltage. Finish by cleaning the drain and double-checking airflow. Bryan also covers: Misdiagnosed compressor failure Parts needed for replacing a compressor What makes a compatible replacement compressor? Billing and pricing Alloys and fluxes Replacing TXVs, capacitors, contactors, and reversing valves Cutting vs. unsweating Suction driers and pressure drop Charging considerations If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE.

In this short podcast, Bryan explains what it means to top off, drop in, and retrofit refrigerants. He describes the differences between those three things to dispel some of the confusion they may cause. Topping off a system means that you add refrigerant to a low existing charge to get it back up to a normal level. In some cases, people top off systems with dissimilar refrigerants (e.g., topping off R-22 systems with cheaper R-407C). Topping off a system with a dissimilar refrigerant is unacceptable, as it's against EPA guidelines and leaves you with an undefined refrigerant mixture. You're only supposed to top off a system with the same refrigerant that's already in it. High-glide refrigerant blends can be tricky to top off when there is a leak, as one refrigerant type may leak more quickly than the other and leave you with a different chemical profile. So, you're better off recovering and starting over when you have lost a significant amount of charge to a leak. If you want to recharge an entire system by recovering the existing charge, you would instead be using a "drop-in" refrigerant. There are no drop-in solutions for R-410A systems. However, some commercial equipment manufacturers can offer information about drop-in solutions, though they are relatively rare, especially as oil has changed over the years. When you drop in refrigerant, you don't have to change O-rings, Schrader cores, or other components. Drop-ins are NOT necessarily like-for-like when it comes to charging. "Retrofit" is a relatively broad term that refers to any type of refrigerant change. The retrofitting practices that may have worked for A1 CFC systems to A1 HCFC systems will NOT work for A1 to A2L refrigerants. We need new installations for flammable refrigerant systems. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE.

Trevor Matthews, the founder of Refrigeration Mentor, is back on the podcast. This time, he and Bryan talk about the value of networking for HVAC techs as the conference season comes to a close. Many trade events are networking opportunities that allow you to build relationships with other tradespeople, educators, mentors, and even other companies. You can also learn many trade and business tools that help you as a technician. Many technical and business conversations occur at trade events, and there is a lot to learn from those, whether you're directly involved or just listening. It can also be useful to sit in on classes or presentations about topics that you don't directly deal with, such as building science. Networking also has value for technicians because it can provide several means of personal development. Making connections with potential mentors can open the doors to new career opportunities, even in places where you wouldn't have expected yourself to work. If you see someone you want to talk to at an event, feel free to go up and talk to them. Trade events are places where people expect to get to know one another, so many of the people who attend them genuinely want to talk to others in the trade. People like Trevor are happy to share their knowledge and help you develop yourself as a technician. You can also send people emails introducing yourself to them before the event if you're a bit introverted and uncomfortable putting yourself out there. Trevor and Bryan also discuss: Being isolated in a "bubble" Choosing to work or visit conferences Networking to avoid getting stuck Planning trips around trade conferences The 2023 HVACR Training Symposium Specialized conferences Refrigeration Mentor Learn more about Trevor's work at https://refrigerationmentor.com/. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE.

David Richardson of NCI joins the HVAC School podcast to talk about how we can implement educational growth effectively throughout the trade. NCI started as a premium training resource about airflow testing, but the organization eventually started teaching about combustion testing as well. When we improve the industry, we need to be able to have concrete ways to see what we've been doing wrong or what we can do better. Test instruments allow us to see the whats and whys behind what we do. Education needs to be focused on bringing those test instruments into training AND teaching others how to use them properly. Once we find a way to understand the invisible aspects of what we do, we can get into systems thinking and grasp the more abstract concepts much more easily. When people are introduced to concepts in a logical sequence, they can build their knowledge on what affects the system and why it does do. When we tie everything together, including using solid data, testing in and testing out, and using sources to help you interpret data, we can implement educational growth more effectively. Most of all, we can learn how to translate the technical into practical, which helps us communicate with the customers in ways that matter. However, the most important thing about test instrumentation and applying it to learning is understanding why you are doing those tests or why you want to do them. David and Bryan also discuss: The purpose of traverse tests The mechanics of NCI's teaching (PATH to performance) To charge or not to charge for combustion analysis What NCI does and how to get involved with NCI Learn more about NCI or get involved with their training at https://nationalcomfortinstitute.com/. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE.

Corbett Lunsford of Home Diagnosis joins Kaleb to record a podcast about comfort investigation on TV. The two of them discuss how comfort investigation works on TV shows, what Home Diagnosis hopes to accomplish, and some building performance tips. Home Diagnosis is mostly aimed at homeowners, but HVAC technicians would also benefit from the show, as it dives into science and testing. The show promotes consumer education and contractor accountability. Diagnostics and testing are absolute MUSTS for providing the best possible solutions and transforming your business. You put yourself in another league when you take measurements and have the data to create tailored solutions. In other words, you can't manage what you can't measure, and if you're not testing, you're guessing. The current paradigm shift in the industry has to do with custom designs. Physics, chemistry, and microbiology are all important facets of applied science to consider when coming up with a custom solution. Many buildings have distinct microbiological profiles, including bakeries with yeast or cheese production or aging facilities. Natural events and human activity can change these buildings' microbiological profiles. Ventilation is part of the equation of home performance, and it's a pretty delicate one that HVAC techs can control. When it comes to ventilation, we would be wise to avoid selling products we don't understand. Ventilation solutions may also be appropriate for one structure but inappropriate for another, so we need to think about the applications of these solutions. Corbett and Kaleb also discuss: Comfort vs. efficiency vs. control ERVs vs. HRVs and humidity How the market influences custom solutions Preview of challenges in Season 3 of Home Diagnosis Microbiology of structures Learn more about Home Diagnosis at https://homediagnosis.tv/. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE.

Blake Standen and Omar Tabba of BrainBox AI join the HVAC School podcast to talk about commercial HVAC predictive control. This conversation focuses on applying artificial intelligence to existing building systems, including the HVAC, to predict performance under certain weather and occupancy conditions. If you have controls that can predict performance and adapt, then you can maximize energy savings. A commercial HVAC system may include air handlers, chillers, boilers, RTUs, and all sorts of energy-consuming technologies. These systems also have controls that help direct the infrastructure, and artificial intelligence can help optimize the controls, make performance predictions based on forecast data, and make those controls communicate with foreign controls from other companies (such as via BACnet). BrainBox AI uses a cloud to collect and hold the data it needs to predict what a building will do and help control the infrastructure. Controls react to errors, and the goal of BrainBox AI is to predict errors before they happen. For example, AI can help solve short cycling under certain weather conditions. However, buildings that use pneumatics rather than digital controls and older systems may not be good candidates for AI solutions. One of AI's challenges is that it requires multiple layers of training: you're training the controls engineers, facilities staff, AND the AI itself. Another challenge of AI is that people don't fully understand that it's not the type of automation that takes people's jobs; we can minimize those perceptions with education. Blake, Omar, and Bryan also discuss: Machine learning vs. artificial intelligence Accuracy of prediction models Virtual testing environments Apathy as a challenge What happens when controls go offline or are adjusted? Tethered services Application programming interface (API) Controlling comfort and energy consumption vs. greenhouse gas emissions BrainBox's global partnership with ABB Learn more at https://www.brainboxai.com/. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE.

Chris Micallef, the CEO of Falkonair, joins Nathan Orr at AHR to discuss energy savings for three-phase equipment. They also explore some of Falkonair's controls for compressors, especially on DC inverter equipment. Falkonair has software that allows users to control all types and brands of three-phase compressors with compatible variable frequency drives (VFDs). The software recommends the compatible VFD based on the amperage readings. Falkonair aims to bring this software to the refrigeration industry and then move on to HVAC contractors and data centers. The control unit adjusts the compressor speed to respond to changes in refrigerant charge levels (based on discharge temperature). These controls protect the compressor and maintain efficiency, even under less than ideal operating conditions. Energy efficiency can increase by 35% with Falkonair's control units in place. You can expect longer runtimes, a reduction in short cycles, and a reduction in humidity. If the refrigerant loss is too great, then the control can also shut down the compressor. However, it should take less time for a facility manager to notice that refrigerant loss is happening. The controls use temperature probes, so they don't cut into the refrigeration circuit. Although VFDs are good for reducing vibrational wear and tear, we have to be aware of potential issues with harmonics. Harmonics can damage the bearings, especially on pumps that don't have oil constantly lubricating the bearings. Chris and Nathan also discuss: VFD sizing considerations How Falkonair's AI works with hot gas bypass Software commissioning Oil return sequences on DC inverter systems Hertz ranges and limitations per compressor type How Falkonair's control units can exceed 35% efficiency gains Learn more about Falkonair at https://falkonair.com/. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE.

Brynn Cooksey joined Eric Kaiser for a podcast about internal apprenticeship, its benefits, and how to make it work. Brynn is the general manager of Air Doctors Heating and Cooling LLC, a well-respected HVAC contracting company in Detroit, MI. Air Doctors Heating and Cooling LLC has its own in-house apprenticeship program based on Department of Labor guidelines. The apprenticeship program caters to new techs out of trade school and focuses on rigorous training. There is some administrative paperwork, but there are no additional administrative expenses. The only expenses of the apprenticeship program come from training and wages. Most of the administrative work comes from recordkeeping. Bumps in pay come with milestones, and RSES certification is available at the highest level of Brynn's program. Once techs receive their RSES CM, they become official journeymen and continue to learn more about the trade through incentivized training. The technicians at Air Doctors seem to like the training program. The program is very structured when it comes to training, hours, and pay, so the techs like predictability. Reduced callback rates are positive effects of the apprenticeship program; Brynn's current callback rate is less than 1% (was 3% before the program was put into place). The apprenticeship program is easy to set up with the government, and it makes companies eligible for national and local grants. Approved apprenticeship programs can also take advantage of other benefits, including labor scouting to grow the workforce. Everything about the apprenticeship program recognition process was free. Many businesses can take advantage of these programs to grow their workforce and train promising technicians who can transform the business. Email Brynn for more information at [email protected] If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE.

Alex and Nicole of Faraday join Kaleb Saleeby and Ty Branaman to talk about new educational formats and options in the HVAC industry. Alex is the founder of Faraday, and Nicole is the head of operations. Ty is a notable HVAC educator who supports Faraday and its mission. Faraday is a free educational program that prepares apprenticeships for fieldwork, allows them to get EPA 608 certification, and helps place them in jobs with paid training. Although the program is free, there is a rigorous selection process to make sure only the most serious candidates join the program. The human aspect is very important to training, and Ty is one of the people who brings that to education programs. HVAC training is multifaceted, and the appliances are just the beginning. Training focuses on science and math as well as craftsmanship, which isn't what a lot of people think about when they think of HVAC. Faraday focuses on bringing the abstract and artistic concepts of the trade to training. However, Faraday also acknowledges just how important skills are to a person's career and life in general. Faraday also has live sessions with guest speakers, and these are available to current students and alumni. Lifelong learning and investment are important to Faraday, and the programs create a support system for students even after completion. Alex, Nicole, Ty, and Kaleb also discuss: Faraday's admissions process Ty's contributions to education and the industry Bringing the Masterclass format and delivery to HVAC The ambitions, interests, and fears of young people Costs of training Using Discord for communication and training Teaching life skills Faraday's vetting, coaching, and weed-out processes Producing coachable, well-rounded individuals If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE.

Ashley (aka hvac_ash) joins the podcast to talk about how HVAC fits into social media, AHR 2022, and AmRad capacitors. Ashley works with Global the Source on the sales and distribution side of the business. Becoming an HVAC influencer is smart, especially when there is a dedicated audience in the industry. When you gain traction online, that can branch into marketing, which helps get the word out even more. It's also a great way to make connections organically once you have traction and learn from others' industry-related content. Ashley also has firsthand experience with the HVAC trade's obstacles for women. She believes that making groups like Women in HVACR more marketable and focusing on recruiting young women will help break those barriers down. There needs to be more effort to the recruiting process than just posting ads and job postings on social media. Global the Source is a distributor of AmRad products, including the well-known American-made capacitors and Turbo line of start capacitors (Turbolytic) and hard start kits (TES5). The quality of the AmRad capacitors' foil and the oil has been tested widely, even on the HVAC School YouTube channel; the conclusion is that AmRad capacitors are made of high-quality materials and last longer than many others. Ashley and Bryan also discuss: What it means to be a master distributor Being an HVAC influencer on Instagram Visiting AHR as an influencer and sales professional Strategic recruiting for underrepresented demographics AmRad's Turbo product family New AmRad products for failed run capacitors and stuck relays Follow Ashley on Instagram (hvac_ash) and DM her with questions or email her at [email protected]. Learn more about Global the Source and some of the AmRad products at https://globalthesource.com/. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE.

Bill Spohn joins Eric Kaiser and Kaleb Saleeby at AHR 2022 to talk about his experiences designing and living in a home with NetZero HVAC. NetZero HVAC refers to system design with tight coordination with the house to make it as efficient as possible. Some of these systems are so tight and efficient that they approach passive house standards (0.6 ACH50). Bill lives in a modular home that also generates more energy than it consumes, and it doesn't rely on natural gas. The greatest expenses of Bill's NetZero home came from all the custom factors, as it didn't make sense to price many of the features on a square-foot basis. The heating and cooling system is also unique, as it is completely separate from the ventilation system, which is a Build Equinox CERV. On the IAQ side, the CERV monitors outdoor temperature and humidity, indoor CO2, and indoor VOCs. Bill also has a HAVEN central air monitor inside the CERV system as a backup. Bill's HVAC system is an air-source heat pump that provides two tons of heating and cooling and has low-temperature capabilities. The two-ton unit works for a 4400-square-foot home. Bill, Eric, and Kaleb also discuss: Energy independence Controlling radiant heat gains and window construction Construction and material fabrication Monitoring energy usage Energy recovery ventilation (ERVs) Thermal bridging at work in Bill's walls Knowledgeable customers Jim Bergmann's help with troubleshooting Radon issues Bill's podcast Solar inverters Measuring tool accuracy You can learn more by listening to Bill's podcast, Building HVAC Science. You can subscribe to the podcast on any podcast app of your choice or get an overview at https://buildinghvacscience.libsyn.com/. You can also check out Bill's blog at https://spohnhome.com/. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE.

Collin Olson, the staff physicist of The Energy Conservatory (TEC), joins Eric Kaiser at AHR 2022 to talk a bit about data logging. Data logging refers to the act of using sensors to record data over time and then analyzing that data. TEC dipped its toes into data logging with the APT and then TECLOG. Data logging allows us to take and store multiple readings as well as extrapolate data into graphs, making it easier to analyze performance. The TECLOG4 software is the most up-to-date version. TECLOG is a simple software to use with basic training. The understanding of building science continues over a lifetime, but the actual software can be learned in approximately 30 minutes. TECLOG is free with TEC's hardware, such as the DG-1000. To get started, all you need is a precision manometer and a computer. However, it's worth nothing that the DG-1000 stores a lot of data, meaning that you can launch data logging sessions on the gauge without your computer. Some of the most important measurements are related to drafts and backdrafting. There are 250 Pascals in an inch of water column, and the DG-1000 can pick up very small changes in the Pascals and can indicate when depressurization happens and when it poses a risk. Improperly installed vents can also produce alarming drafting conditions due to air density; data logging can pick up that sort of information. Collin and Eric also discuss: The history of TEC's APT Wind and its effect on building pressures Event markers and hotkeys The link between depressurization, flue gases, and weather conditions Managing multiple blower doors at a time Check out TEC's software, including TECLOG4, at https://energyconservatory.com/downloads/. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE.

Mark Tozzi from Carrier comes on the HVAC School podcast to talk about unique HVAC incentives in K-12 schools. When schools closed down during COVID-19 lockdowns, a new series of incentives came out for schools. Many of these incentives include access to technology, and improvements to HVACR equipment are covered under those programs. Schools can benefit from geography-tailored solutions, including air-cooled chillers in the Southeast and products meant to improve IAQ, including filtration upgrades and dehumidification strategies. To provide valuable solutions to schools, HVACR professionals and manufacturers need to get involved in local conversations, such as on school boards or at the district level. The incentive is quite broad, and it provides schools AND HVACR professionals with many opportunities. The funds need to be spent by 2023, so we can focus on doing business with schools this year. However, as we seize these opportunities to help our communities, we also need to make sure that we have the labor, training, and ambassadorship to make these initiatives successful. As an industry, we need to focus on recruitment and training to stimulate interest in the industry. Not to mention, as equipment advances, technicians need to be able to catch up with newer technology. The COVID-19 pandemic has put our industry into the spotlight, and people are paying more attention to their air quality and our work than ever before. Through community opportunities, recruitment, and education, we can hope to improve our industry. Mark and Bryan also discuss: OptiClean air scrubbers Buy boards How the HVAC industry might appeal to younger generations When are HVAC contractors seen as valuable to the general public? Learn more at carrier.com. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE.

Chris Forth, the VP of regulatory codes and environmental affairs at Johnson Controls, joins Bryan for a live podcast at AHR 2022. This time, they discuss changing HVAC regulations and what that will mean for contractors, technicians, and installers. Johnson Controls focuses on institutional chillers, controls with digital platforms, air handlers, filtration, and alarm systems. Lately, Chris has gotten the industry ready to convert existing products and systems to high-efficiency equipment for low-GWP, A2L refrigerants. The transition to A2L refrigerants will be different from the transition from R-22 to R-410A. We needed to change the oil type (mineral oil to POE) and make equipment for different pressures when we went from R-22 to R-410A. However, the pressure and oil needs of A2L refrigerants are very similar to R-410A; the main obstacle is dealing with mild flammability. Every six years, the U.S. Department of Energy (DOE) sets minimum efficiency standards, and they determined that it's time for an upgrade. In other words, 14-SEER straight-cool A/C systems will no longer cut it in some places. In the Southeast, equipment that doesn't meet the new standards must be INSTALLED before 2023. (In other cases, the date of manufacturing is what matters.) Now, contractors need to be sure that they can install 14-SEER units before 2023 if they order them. Otherwise, contractors may be better off ordering 15-SEER units now to ensure that they can install the equipment. Chris and Bryan also discuss: North vs. south efficiency ratings AHRI match How manufacturers will be affected by these regulations American Innovation and Manufacturing Act (AIM Act) The self-extinguishing properties of A2L refrigerants Learn more about Johnson Controls at https://www.johnsoncontrols.com/. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE.

Kevin Hart, the CEO of HAVEN, joins Kaleb Saleeby live from AHR 2022 to discuss how we can control IAQ with central air monitors and controllers. HAVEN, formerly TZOA, is an IAQ company that focuses on protecting building occupants' health by controlling air quality. HAVEN's approach to managing IAQ starts with collecting data about the air. Without that data, we can't come up with solutions tailored to individual buildings. We need sensors to gather that data, which would traditionally mean that we'd need a decentralized system with sensors everywhere. However, HAVEN takes a centralized approach to measuring and controlling indoor air quality. HAVEN's central air monitoring system is not an ordinary box product. Monitors constantly provide data that help HVAC professionals find points of improvement in a home and form a solid professional relationship with homeowners. The goal is to use data as a bridge to connect the homeowner and contractor as well as build trust. One of HAVEN's new projects is to expand into remote HVAC diagnostics. The search for deviations in heating, cooling, and comfort will allow HAVEN to get more involved in the HVAC industry and communicate diagnostic help and solutions more effectively. Kevin and Kaleb also discuss: HAVEN's name and vision Avoiding false positives for harmful substances with centralized monitoring Equipment longevity Stagnancy of air in homes in moderate climates The issue with constant 50% relative humidity Outdoor air quality and comparative analysis IAQ as a luxury rather than a necessity Predictions for the HVAC industry Learn more at https://haveniaq.com/ or become a HAVEN Pro today at https://pro.haveniaq.com/. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE.

Jacques Beaudry-Losique, the CEO of Enginuity Power Systems, joins Nathan Orr live at AHR 2022. Enginuity manufactures energy-efficient engines that produce more power than traditional engines and recover waste heat to act as water heaters. Enginuity engines can run on propane and natural gas to help you run almost entirely off the grid and participate in electricity buyback programs. These units operate independently of the electrical grid and can act as generators during power outages and have a small footprint. However, a backup battery system is recommended for these units to maximize efficiency. Enginuity has a residential and commercial line. The E | ONE is best suited for residential applications, and the E | TWO is better for heavier commercial applications. The U.S. Army has been one of the most prominent supporters of Enginuity, which also manufactures its units exclusively in America. Distribution is done through a third party, including business owners and technicians; Enginuity doesn't deal directly with homeowners or building staff. As a result, A/C service technicians, installers, plumbers, and refrigeration technicians may end up being the people in the middle who do maintenance on Enginuity generators. After this conversation with Jacques, we are very interested in seeing what the future holds for Enginuity and combined appliances. Jacques and Nathan also discuss: The electrical grid's stability Enginuity's revolutionary piston design Ease of startup and commissioning Pricing questions Enginuity's target market and training resources for that target market Engine life expectancy Enginuity's projected rollout timeline and expansion plans Decentralizing power dependence Solar vs. fossil fuel energy The problem with power plants Learn more about Enginuity at https://enginuitypowersystems.com/. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE.

Rick Nadeau, Director of Training and Technical Services at Samsung, talks with Kaleb Saleeby live from AHR. He explains some of the exciting ductless solutions that Samsung has to offer. Samsung's WindFree mini-split systems work with VRF systems or as normal ductless units. The WindFree product line is best known for preventing drafts due to microholes. These systems come in one-way and four-way cassettes and work very well for sensitive environments like nursing homes and bedrooms. These units also have humidity sensors that let the units know when it would and wouldn't be acceptable to go into WindFree mode. Samsung's systems may also have occupancy sensors, which determine when they can turn on to provide comfort and flexibility. The systems also have the capability to determine when the system is losing refrigerant to prevent major environmental and performance issues. Samsung has MaxHeat technology, which allows a system to have 100% heating capacity in low-ambient temperatures as low as -30 degrees Fahrenheit. So, the lack of reliance on auxiliary heat can reduce energy consumption and costs under most conditions. In general, much of Samsung's innovative technology is introduced across entire product lines. In the commercial sphere, Samsung's DVM S is an influential modular chiller and water heating system. Its flexible design (thanks to VRF technology) has made it a popular choice for product storage in vineyards. The DVM S Eco also has heat recovery capabilities. Rick and Kaleb also discuss: Stratification prevention and high-ceiling configurations Air velocity and unit cleanliness Refrigerant loss detection Learn more about Samsung's ductless systems and online training programs at https://www.samsunghvac.com/. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE.

Steve Rogers from The Energy Conservatory (TEC) joins Eric Kaiser to talk about airflow measurement at AHR 2022. Steve is an expert in fluid dynamics and flow measurement, and he is a trainer in addition to being the president and CEO of TEC. Airflow is one of the most critical elements of an HVAC system; it allows us to move the correct amount of BTUs to condition the air properly. We have various ways of measuring system airflow and airflow to a space. We can use the TrueFlow grid for the former and flow hoods for the latter. When it comes to measuring airflow, calibrating the instrumentation is crucial. TEC uses a laboratory-grade orifice plate to calibrate the tools. So, the calibration process manages to yield high accuracy while using a low-maintenance device. To begin measuring airflow properly, start taking the total external static pressure (TESP) and looking at fan charts. TESP doesn't actually measure airflow, but it provides an idea of what the airflow might be like, and it's a practical, useful measurement in the field. The TEC TrueFlow grid has recently been upgraded, and it's a good step up from taking the TESP and referencing fan charts. It goes into the filter slot and measures the CFM per ton as well as the static pressure. Steve and Eric also discuss: Airflow's effect on latent and sensible cooling Blower door setups and chambers References for accuracy Relationship between static pressure and airflow Is the hand-ometer an acceptable form of airflow measurement? Challenges of pitot tubes and hot-wire anemometers Learn more about The Energy Conservatory at https://energyconservatory.com/. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE.

Brett Wetzel and Kevin Compass from the Advanced Refrigeration Podcast join us to discuss commercial rack refrigeration and identify components. In supermarket racks, we typically have anywhere from 2-5 compressors on a single rack (with multiple evaporators, metering devices, and sometimes even condensers). These compressors may come in several varieties (including screw and scroll) and be digital or have VFDs. They also have common suction and discharge headers. The compressors all share oil from a single system. Oil separators can come in three varieties: centrifugal, impingement, and coalescing (most efficient). The separator would feed into the reservoir, which stores oil. Many rack systems use several different valves. Check valves to direct the refrigerant flow, especially on heat reclaim systems and split condensers. In some cases, there is a three-way valve or a solenoid valve that controls or stops the refrigerant flow. LDR (liquid differential regulating) valves maintain the required differentials during defrost. Ball valves can be found all over a rack (liquid line, suction line, discharge line, etc.) and can isolate a line. Standard and balanced-port TXVs or EEVs may also appear on racks. There is also an EPR, which controls evaporator temperature and pressure. Grocery systems have a drop leg before the receiver, which stores liquid refrigerant. We want a full column of liquid leaving the receiver, which we can confirm with a sight glass rather than subcooling. Brett, Kevin, and Bryan also discuss: Reheat and excess heat Split condensers Drain leg/drop leg vs. liquid line Mechanical subcooling and heat exchangers Counterflow piping Hot gas vs. Kool gas defrost Standard vs. balanced-port TXVs Distributors Evaporator fin spacing Cleaning components Check out the Advanced Refrigeration Podcast on any podcast app of your choosing. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE.

Jim Fultz from Emerson joins Eric Kaiser at AHR to share his knowledge of universal boards and controls. Jim's work focuses on electronic controls within the White-Rodgers brand. Common White-Rodgers universal controls include the SureSwitch and universal defrost controls. The SureSwitch also has sealed contacts, which prevents insects and debris from shorting out the contacts. This past year, White-Rodgers debuted the All-Spark, which doesn't need electricity to be powered up and can be programmed right out of the box. The All-Spark works on all sorts of appliances, not just boilers and furnaces. Universal controls are generally safe to put in combustion units, even gas furnaces. New controls go through rigorous testing before they hit the market. The controls MUST stay within the OEM's guidelines; otherwise, they won't make it to the market. Sometimes, when boards need to be replaced, we also need to upgrade the igniter to match the voltage of the new board. The goal of universal controls is to save time and hassle for the technicians and the customers, which makes it easier to make sales. It's also easier for the distributor to get fast and accurate solutions to the technicians, especially when OEM parts may not be immediately available due to supply chain issues and normal shipping expectations. Jim and Eric also discuss: All-Spark benefits and features Manufacturer-specific vs. general universal controls White-Rodgers nomenclature Controls instructions Distributors and sales reps Evolution of controls for direct-spark and hot-surface ignition Training techs to install controls on equipment Learn more about White-Rodgers controls at https://climate.emerson.com/en-us/brands/white-rodgers. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE.

In this short podcast from AHR 2022, Leilani Orr and Eric Kaiser talk with the president and CEO of Malco Tools, Rich Benninghoff. Rich discusses some of the exciting new tools that Malco is bringing to the market and some plans for the future, especially when it comes to education. Malco has developed the Eagle-Grip, which is a set of locking-handle pliers made in the USA with American steel. The tool is currently in a soft launch; it is currently receiving a lot of interest, so Malco has been building up inventory, forming partnerships across industries, and collecting market feedback. One of Malco's most exciting products is the C-RHEX line of cleanable, reversible magnetic hex drivers. These hex drivers come in many sizes and are easy to clean; the cleanable and magnetic features are especially important, as the buildup of metal resin and clippings can decrease tool longevity and effectiveness without proper cleaning. Malco has also been focusing on trade schools and education through "Look Good, Feel Good, Do Good." The initiative gives back to the community and provides career and education-enhancing opportunities to young people who are serious about the trade. Over the next decade, expect to see Malco continue investing in product innovation. Rich is excited to grow the brand and help the HVAC, automotive, and other industries along the way. Rich also covers: Malco's history with sheet metal fabrication Relying on customers for feedback and ideas "Head of the Class" program Providing tools for shop classes in local school districts Learn more about Malco Tools at https://www.malcoproducts.com/. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE.

Jason Obrzut joins Nathan Orr with the HVAC School podcast live from AHR. In this episode, they discuss A2L refrigerants and upcoming regulations. They explain what a "flammable" refrigerant really is and why the industry may be making a bigger deal of the new regulations than is really necessary. Whenever regulations are passed, we need to understand that there is a notable transition period. This period will mostly be about training, and the only people who should be working on the new equipment should be the most experienced technicians. A2L refrigerants are mildly flammable, non-toxic refrigerants, including R-32. Flame propagation is possible but quite rare for A2L refrigerants under normal operating conditions. However, even A1 refrigerants can propagate flame under the right conditions (just not ones we'd normally see). Many countries all over the world have been using A2L refrigerants for much longer than we have, so we can make those refrigerants work safely. All trades will evolve, and we need to be prepared and trained to adapt to changes over time. When we learn all the new practices that come with these new regulations, we become better technicians. The only place where we can make a difference is in our work, so it pays to focus on learning new things instead of resisting change. Jason and Nathan also discuss: A2L vs. A1 vs. A2 vs. A3 refrigerants What does "flammable" really mean? Recordkeeping regulations for A2L refrigerants Getting over the fear of the unknown Why the HFC phasedown is NOT driven by refrigerant manufacturer profits Learn more about ESCO's HVAC Excellence conference HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE.

David Holt with NCI returns to the podcast to discuss the evolution of HVAC training; we cover the past, present, and the possible future of training in the industry. In the past, we had a lot of hands-on training, whether it was one-on-one or in a traditional classroom setting. These learning practices remain beneficial today, especially since many uninformed practices are still prevalent in the industry today (charging to beer-can cold, condemning TXVs without a second thought, etc.). However, the pandemic has forced us to consider online and remote training in the present. The content has also changed from the past; we are a lot more aware of combustion and airflow nowadays, which are very important topics for safety and efficiency. Those training topics allow us to understand what we're doing when we take the "vital signs" of the equipment. Being better versed in basic and advanced diagnostics will also give us a more holistic understanding of the HVAC equipment as a system, which can help us truly optimize the systems instead of changing parts and making band-aid fixes. Moving forward, we can expect HVAC training to use virtual reality to help bring traditional hands-on training to the online sphere. We can't expect a perfect replacement, but we can expect improvements in technology to close the learning gaps that result from online training. David and Bryan also discuss: NCI training during the pandemic Components vs. systems ASHRAE Standard 221-2020 Older educational resources and standards Occupational safety Pricing Online classes, podcasts, and other modern training media Learn more about the National Comfort Institute (NCI)'s training and sign up HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE. Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Jim Bergmann returns to the HVAC School podcast live from AHR 2022 to discuss a bit about proper system commissioning. He explains the commissioning mindset and some helpful procedures. Successful system commissioning starts with the mindset. A good commissioning organization broadens its vision; instead of focusing on the appliance, techs and installers focus on the system. Commissioning early on saves time later; you can focus on installs and maintenance instead of callbacks, and your organization can make more money as a result. When installing and testing new piping, make sure you insulate the tubing properly and keep the lines CLOSED OFF to the atmosphere. Measuring the line set is also critical for weighing the charge properly, as long lines have special considerations. When doing the decay test, use a quality vacuum rig and try to keep the micron gauge as far away from the pump as possible. Cleaning line sets also helps your vacuum results by getting rid of oil and moisture within the lines. Flowing nitrogen while brazing and sweeping with nitrogen are two other important installation/commissioning practices. They may seem idealistic, but it's easy to adopt these practices widely and reduce problematic scale buildup. Methods for setting airflow have changed over time. Nowadays, the best practice is to take a volumetric flow measurement (such as with a TrueFlow grid). Jim and Bryan also discuss: Preventing callbacks and warranty returns Evacuation and dehydration Factory practices One-hose evacuation with large hoses Flushing the line sets with pigs Nitrogen flow regulators "Airflow before charging" and metering devices Special considerations for MicroChannel coils If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE. Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Russ King joins us for a short podcast episode about using 3D load and energy calculations with duct design. Russ has developed the Kwik Model 3D software program with the help of his son, Connor. Kwik Model 3D uses a video game platform to build a house out of boxes instead of a sketch. The software has evolved and been integrated into EnergyGauge to do load and energy calculations based on a house's geometry. Kwik Model makes it easy and fun to create that geometry profile for a home, which makes building design and load calculation attractive to technicians. Software like Kwik Model may especially become popular as Generation Z steps into the workforce; we can expect the learning curve to be quite shallow for the digital generation. The Manual J calculation uses the home's characteristics in Kwik Model and does all of the mathematical calculations in EnergyGauge for an advanced load calculation. KwikModel then receives those calculations for each room. Then, you can draw the ductwork and use an auto-size function to get the proper duct size based on the calculations. Energy simulations use several load calculations with advanced data to figure out what the energy usage will look like in a home with a certain set of load conditions. Russ and Bryan also discuss: Modeling quickly with Field Draw How building materials impact load calculations and energy simulations Energy simulations vs. load calculations Upcoming events with Russ King Kwik Model's tech support Using the Unity platform to develop software for many different industries Learn more about the software and get your 30-day free trial at kwikmodel.com. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE. Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

In this live podcast from AHR Expo 2022, John and Mike Pastorello of Refrigeration Technologies give us a history lesson in HVAC chemical chemistry. They also explain what it takes to make a truly beneficial product for the industry. From the beginning, Refrigeration Technologies has focused on solving problems instead of jumping on product trends. Before Big Blu was introduced, technicians had to rely on less-than-reliable electronic leak detectors and poor-quality soap bubbles. So, John Pastorello learned about the fundamentals of foaming and bubbles to create a leak reactant that works, even creating microbubbles for tiny leaks. Nylog has a similar origin story, and it has evolved to work for both mineral oil (red) and POE (blue) systems. As with Big Blu, John ran several tests to make sure the Nylog was compatible with HVAC equipment and did not cause contamination. The Viper Pan & Drain Treatment was developed to replace pan tabs, which failed to remove the dead biological material in drains. The spray coats the whole pan and dissolves sludge with enzymes. The Venom Packs are highly concentrated cleaners that arose from a move to consolidate the chemical line into something lighter, smaller, and faster. (Think about laundry detergent pods.) So, Venom Packs were inspired by laundry detergent and developed into a concentrated product line with recommended dilution ratios. Mike, John, Jessica, and Bryan also discuss: All the considerations that go into creating a leak reactant "Controversial" uses for Nylog Nylog white pipe dope for gas, water, air, and glycol Overcoming drain/pan odors Enzyme-based cleaning Safety considerations with HVAC chemicals Durability of Venom Pack packaging Family businesses Women in the business Learn more about Refrigeration Technologies at refrigtech.com. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE. Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Michael Housh returns to the podcast to discuss upgrades and proposals that are worth considering. These upgrades and proposals can actually benefit the customer AND lead to clarity and profit without turning you into a white-shirt tech. When assessing a system for replacement, it's a good idea to look at the airflow side by measuring static pressure AND using a flow grid; these practices set you apart from others and supply you with good data about system sizing. Filtration is another area where you can consider upgrades and proposals; customers generally want to keep their air clean and may be happy to pay for better filtration, fresh air, and de/humidification. Surge protection is a high-value upgrade that many customers may benefit from, especially if the electrical company allows overvoltage or the customer has a voltage-sensitive ECM or inverter system. Some upgrades are useful and can be offered automatically (the customer can decline it); depending on the climate, a humidifier or dehumidifier may fit into that category. Proposals are a chance to put all of the offers on the table and allow the customer to select and decline whatever they want. When we adopt this business method, we would be wise to remove our egos from the process. Some processes that add clarity to proposals include creating checklists and taking lots of pictures for the customer. You'll also create trust between you and the customer when you establish that clarity. Michael and Bryan also discuss: HVAC industry game-changers Profit margins Free quoting Fresh air considerations Consistent overvoltage Metal oxide varistors (MOVs) and the ICM493 IAQ monitors Attic infiltration and can lights Proposal verbiage and templates Callbacks and consultations If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE. Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

In this short podcast episode, Clifton Beck joins us to talk about Bluon's free tech support and resources available to technicians and installers. Clifton has been very in touch with the HVAC technician community since he got his start in the trades, and he has taken that into tech support. He has noticed that the inefficiency in our industry tends to come from poorly learned practices, and working in tech support is a way for him to do his part to spread better practices while helping others. Lately, Bluon has become more of a tech support business. The new shift to focus on innovation has prompted Bluon to shift from making equipment more efficient to making technicians more efficient. The whole HVAC industry relies on that progression from developing on equipment to people. Tech support consists of answering calls but also creating training videos and creating layers of technician education and development. Manuals are just part of the picture; tech support helps with part identification AND the sequence of operations. Tech support reduces the amount of time it takes to learn about a part or locate components, which makes technicians more efficient and strengthens our industry. Overall, tech support calls are opportunities to train technicians to do better; they don't just have to give away simple answers that don't really help anyone. Clifton and Bryan also discuss: Bluon's growth Trends in tech support calls Tech support and community involvement Feeling accomplished as a tech support representative Learn more about Bluon's free tech support on the Bluon app, or you can check out bluon.com. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE. Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Genry Garcia returns to the podcast to talk about blower doors and why ACH50 may needlessly complicate efforts to tighten a building envelope. A large element of indoor comfort comes down to controlling the load, especially the latent load. Even though we can control indoor humidity sources, we may also deal with infiltration, which contributes to a high latent load and decreases comfort. The blower door test comes in when we can no longer control the load and need to determine how much infiltration is happening. When using blower doors, we would typically use an ACH50 test, which takes the CFM50 (cubic feet per minute that the blower door moves to get the house up or down to 50 Pascals) and translates it to air changes per hour at 50 Pa. To do that, you would need to find the volume of the space, which adds hurdles that the HVAC technician needs to deal with. However, Genry prefers using the CFM50 and factoring in the square footage and LAIR (leakage area infiltration ratio) to determine how tight a house is; he doesn't focus on the building's volume. To decrease the leakage, it's best to stay focused on the CFM50 the entire time; worrying about the ACH50 just adds an extra step that we don't necessarily use. Genry and Bryan also discuss: Connecting design and execution Attic encapsulation How to use LAIR Ceiling height and stack effect Blower door testing for code compliance vs. comfort consultation/diagnostics Common duct problems in new constructions Balancing supply ducts Automation of communicating controls IAQ products and dehumidification If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE. Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Eugene Silberstein, a co-author of Refrigeration and Air Conditioning Technology (RACT manual), joins the podcast to give us an introduction to psychrometrics. Psychrometrics focuses on the properties of air and its contents, especially as they relate to human comfort. To understand psychrometrics, we need to be able to quantify air: its weight, humidity, pressure, etc. We can do a better job as technicians if we figure out the air's content and see how it relates to the CFM and overall unit performance. That way, we can have a more holistic view of HVAC performance instead of just focusing on adding or recovering refrigerant to improve performance. The psychrometrics chart helps us understand the conditions of the air based on quantities like water vapor, dew point, and more. The chart may intimidate techs, but it contains a wealth of information that can help technicians understand the air and the customer's comfort better. Basic psychrometrics can also help us grasp why furnaces don't actually dry out air; they pull the moisture out of the air and pull it back in, so the absolute humidity stays close to the same. However, we commonly add humidifiers because the relative humidity drops with the temperature rise. Eugene and Bryan also discuss: How air filters and blower motors interact with the air Things that affect the weight of air per cubic foot Humidifying air and its effect on the density of air High-pressure air moving to an area of lower pressure How latent heat works Pressure and the atmosphere Absolute vs. relative humidity Learn about ESCO's e-learning network at hvacr.elearn.network/ and Psychrometrics Without Tears HERE. ESCO also holds the HVAC Excellence Conference; learn more about that HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE. Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Brandon Marshall, Chemours's North American marketing manager for thermal and specialized solutions, joins the podcast to discuss refrigerant changes that are coming and how we can prepare for those. Brandon started in the industry by going to a technical school when he was 14 and has been hard at work ever since, studying light commercial design and going to college in between. Local and global regulations have changed a lot over the years and continue to change as we continue maximizing our equipment's efficiency. California will soon start switching to low-GWP refrigerant on new equipment in 2025; even R-410A can't be used in new equipment. We will begin seeing the rise of A2L refrigerants and moving away from the A1 refrigerants that are more detrimental to the environment; we'll have to focus on safety as we begin working with more flammable refrigerants. As new refrigerants get off the ground, we can expect increased communication between manufacturers and dealers to prepare for the sale of equipment built for the new refrigerants. Although we can't confirm anything, Brandon has speculated that the EPA will soon follow in California's regulatory footsteps when it comes to new equipment and R-410A. It's a good idea to stay educated, subscribe to A2L newsletters, and follow HVAC trends in Europe to predict what might come next in North America. Brandon and Bryan also discuss: Educational resources about refrigerants What "mildly flammable" actually means European HVAC equipment Chemours at the AHR Expo Learn more about Chemours A2L training at opteon.com or Opteon's YouTube channel. Check out what Chemours has in store at the AHR Expo at https://www.opteon.com/en/ahrexpo. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE. Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Chuck Allgood with Chemours joins the podcast to cover the history of refrigerants and discuss what the future might hold. In the late 1800s, before Freon, the only refrigerants that were used were industrial chemicals like ammonia, CO2, and sulfur dioxide. DuPont stepped in to provide a better refrigerant for industrial refrigeration (which then spurred the rise of domestic refrigeration), so they created a non-toxic, non-flammable chemical called Freon-12 (CFC R-12) in 1928. However, in the 1970s-1980s, it was discovered that R-12 and other CFCs depleted the ozone layer due to the chlorine content. R-12 production was banned in the 1990s per the Montreal Protocol. HCFCs like R-22 also have chlorine but in smaller concentrations; those phaseouts have been much more recent. Following news of the HCFC phaseout, HFCs and refrigerant blends became more popular because their ozone depletion potentials were 0. Although HFCs don't deplete the ozone layer, some of them have high global warming potential (GWP). Regulations stemming from the Kigali Amendment, such as the American Innovation and Manufacturing (AIM) Act, have been introduced to phase down the production of HFCs to slow global warming due to refrigerants. HFOs have recently been developed to replace HFCs; these have olefins, which are double-carbon bonds with short atmospheric lifespans. So, they don't contribute to global warming as significantly as HFCs and have GWPs of less than 1. Chuck and Bryan also discuss: What Willis Carrier really invented Chlorine and ozone depletion Development of refrigerant blends Freon vs. Opteon branding Refrigerants and the greenhouse effect Oil lubricants Best practices for mildly flammable refrigerants Timeline of Opteon line refrigerant releases Learn more about Chemours A2L training at opteon.com or Opteon's YouTube channel. Check out what Chemours has in store at the AHR Expo at https://www.opteon.com/en/ahrexpo. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE. Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Andy Holt joins the podcast to discuss the ever-relevant topic of overcoming conflict at work. Some people end up in conflicts often, so Andy recommends paying attention to how others react to the conflict you have perceived; if you are much more stressed than everyone else, then you need to look internally, not externally. The first step to overcoming conflict is to slow down and think about your reactions to perceived conflicts. Partaking in bickering and gossip with coworkers creates a negative environment for the entire team; the best way to avoid or resolve conflicts is to handle them directly and sincerely ask the other party to start over. Overall, it's best to take the high road and take initiative to make things right. When dealing with conflict with bosses, it's best to separate emotion from the facts and keep discussions simply factual. It's good to be open, honest, and understand that you can't control your boss's response. As a boss dealing with employee conflict, it's a good idea to avoid firing on the spot and give employees a chance to think about the conflict at hand, such as by giving them a paid "cool-off period." Customer conflicts may arise from pricing issues. The technician can ease tensions by quoting jobs up front and bundling services to show the customer where the value is. To resolve conflicts with customers, the best thing to do is be attentive to their concerns. Andy and Bryan also discuss: "Designing" a reaction Dealing with big egos Letting people go Working towards agreements vs. forcing bargains Dealing with hot tempers Taking ownership of comfort problems MeasureQuick and fact-based conversations If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE. Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

Matthew and Nick Wavra join the podcast to discuss everything that goes into job estimation in commercial HVAC. Nick has a lot of fieldwork and project management experience, and Matthew has marketing, software, and sales experience, which helps bring in and retain clients. Commercial estimation begins when a mechanical contractor asks for a bid on a job. The estimators go through the spec books, bidding documents, and any addendums to come up with takeoffs and a price. The estimator seeks approval from manufacturers to build the materials, and they use software to come up with an estimate. The pricing updates weekly to stay current and accurate in an economy that's currently facing inflation. Estimators develop takeoffs for materials and labor; each material has some sort of labor attached to it, though the labor estimates may need to be adjusted as conditions change. Commercial contractors may make mistakes when they miss equipment or elevation considerations (when estimating labor). On-screen takeoff options significantly reduce the risk of creating mistakes, so it may be unwise for contractors to do takeoffs by hand instead of using software to help. Matthew, Nick, and Bryan also discuss: Sheet metal price increases Software vs. man-made takeoffs DX piping vs. chilled water boilers Estimation in HVAC vs. refrigeration CRM (customer relationship management) Developing a commercial HVAC estimation training course Finding a niche in the HVAC estimation business Look for Nick and Matthew at the AHR Expo 2022 in Las Vegas! They will be at booth N9142 in North Hall. Learn more about Matthew and Nick's business by visiting hvacestimation.com/ or by calling Nick directly at (238)-900-6330. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE. Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.

In this short podcast episode, Bryan goes over the basic gas furnace sequence of operations. There are a few variations, but the sequence of operations tends to stay consistent across most furnace types. First, a W call from the thermostat calls for heat. The circuit board will then assess the safeties to see if it can bring on the heat without causing flame rollout or other dangerous conditions. If the safety switches are all closed, then the furnace can bring on the heat. However, in some cases, the induced draft motor may come on first in some 80% furnaces. There needs to be a small negative pressure in the induced draft motor housing. To confirm that we have that pressure, a pressure switch will close under the right conditions. Then, ignition begins. In most cases, we use intermittent-spark ignition (ISI) or hot-surface ignition (HSI). It takes some time for these methods to light the pilot, which then lights the main burner. After that, the gas valve opens to fuel the burner. On an ISI system, that's about it until the blower comes on. However, once the main burner opens on an HSI system, a flame sensing rod can verify if you have a flame on that burner. There is a blower delay that prevents the blower from coming on and blowing a bunch of air that hasn't yet been heated. After that, the blower delay ends, and the blower comes on. Then, the furnace shuts off when the W call ends. Then the blower continues running for a little bit before turning off. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE. Check out information on the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.