Hvac School - For Techs, By Techs

Eric Kaiser returns to the podcast to discuss high-voltage wiring, low-voltage wiring, and condensate assemblies as they relate to systems thinking. On the high-voltage side, the disconnect should be in a secure location, and it should be able to keep water out. The wires should be appropriately sized, have an appropriate level of tension, and should not be vulnerable to chafing or abrasion. Overall, best practices include using proper grommets and ensuring that you have a solid connection. Do not run high voltage wiring in parallel with low-voltage or control wiring. It’s also worth noting that double-lugging is a poor practice that is against code. On the low-voltage side, you also need to be careful of where you route your wires to avoid induction, contact with hot surfaces, or abrasion. The insulation ratings also need to be appropriate. We can think of the condensate assembly as its own system. Condensate drains have uphills and downhills, and they may have traps, vents, and cleanouts throughout. Cleanou

Eric Kaiser returns to the podcast to talk about how copper, piping, and line sets play into systems thinking. Nowadays, we have to think about POE and PVE oil, and we need to design line sets in a way that assists with oil carry while preventing liquid refrigerant migration. The height of the evaporator relative to the condenser is a major factor to consider during the design phase. Especially when chases are run underground, we need to watch for possible threats to the copper. Water softener discharge and excess pool water may damage the copper over time, and systems should be designed to keep line sets away from those. In many cases, Florida chases are sealed with mastic, which doesn’t prevent water from getting in (but does prevent rodents and insects from entering the home. Flowing nitrogen is one of the best practices you can do while brazing. Nitrogen displaces oxygen, which contributes to oxidation and produces scale. When cutting copper, you will also want to make sure that you don’t get copper shavi

Eric Kaiser joins the podcast to talk about systems thinking in HVAC. Systems thinking allows us to solve problems and address customers’ comfort holistically instead of focusing on just the equipment. The key to systems thinking is to think outside the appliance. System design plays a major role in performance. Duct design, drain placement, and equipment placement all matter, and we can only do so much to mitigate factors of poor design. We need to assess the building envelope and consider how the HVAC system interacts with it. Building envelope and duct leakage will significantly affect HVAC performance and occupant comfort.  Ventilation also matters, especially since many homes rely on exhaust-only ventilation. However, the air that leaves the building must be replaced, and we often don’t control where that air comes from. When you control the source of your fresh air ventilation to meet ASHRAE 62.2, filtration may further help control the quality of the air that comes in. Installation and commissioning ar

Nathan Orr joins Bryan to talk about some logical fallacies, namely the false cause and strawman. They explain how those fallacies show up in the trade. It’s difficult to present arguments without using fallacies, but people tend to rely on fallacies to uphold extreme religious or ideological viewpoints or conspiracy theories. Fallacies are also often easier to communicate than nuanced science and data. “False cause” relates to the phrase “correlation does not equal causation.” It can be tempting to link coincidences and say that one thing causes the other, but that could very well not be true. For example, more compressors fail during lightning storms. It’s reasonable to assume that lightning causes the failures, but lightning is not simply striking all of the compressors; other power outages and other conditions that happen during storms are more likely plausible causes. Confirmation bias also makes it easy to cling to a false cause. People are likely to disregard data that doesn’t align with what they alre

Refrigeration Mentor founder Trevor Matthews returns to the HVAC School podcast to talk about personal development and training, including tips for learning in HVAC/R. When you’re looking at a problem in the field or in training, it pays to take a step back, cool down, and reevaluate your mindset. Trevor recommends thinking about the worst-case scenario and seeing how you can either prevent it or grow from it. It’s good to walk away for a little bit anytime you feel like you’re overanalyzing anything so that you don’t make blunders.  Trevor has found that reading books is one of the best ways to learn about HVAC/R. HVAC/R professionals can greatly benefit from investing in themselves and setting up their own self-directed training programs. Trainers and mentors can’t be the only ones motivating HVAC/R professionals, holding them accountable, and stimulating their growth. Many times, our own limiting beliefs of ourselves hold us back, and we need to convince ourselves that we can learn difficult things, even i

In this short podcast episode, Bryan shares some of his top threaded connection tips. He also clears up some confusion about connection types. Threaded connections include flare and compression-type fittings (like chatleff or Aeroquip fittings). The threads don’t actually make the seal; the pressure pushing the surfaces together is what makes a seal.  Bryan doesn’t recommend putting traditional thread locks on flares, but refrigerant oil or mild assembly lubricants can help the flare come together more smoothly without imperfections. However, you need to be careful when using a torque wrench and use the lowest acceptable specification to avoid over-torquing.  Leaks are common problems with flare fittings, but those often happen in cases where flares are poorly made. Scored faces, loose flares, and over-torqued flares are common causes of leaks. However, many modern flaring tools can make perfect flares quite easily. You must also remember to deburr the copper for the best results. Compression-type fittings of

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 them

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 H

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

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 redir

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

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 int

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 ne

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 transfor

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

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

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 impo

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, es

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

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 g