HVAC School - For Techs, By Techs

In this short podcast, Bryan talks about THOR, total heat of rejection. He explains what it is and why we should care about it when working on HVAC/R systems. THOR is another aspect of pressure-enthalpy calculations, along with net refrigeration effect (NRE) and total heat of compression. When we talk about system capacity, we're often referring to heat absorbed in the evaporator coil (NRE).  Heat...

Matteo Giovanetti from Micro-Air joins the HVAC School podcast to talk about the differences between a hard start and an EasyStart. Micro-Air's "EasyStart" provides a soft start rather than a hard start. A hard start abruptly ramps up the voltage and current to the motor start; a soft start is a much gentler start that results from a gradual voltage and current increase on the start AND run windin...

In this short podcast, Bryan explains what the heat of compression is and why we should care about it as HVAC/R professionals. More heat is rejected in the condenser than absorbed in the evaporator coil, and that's because the compressor adds heat. That added heat is called "heat of compression." That heat does NOT contribute to the net refrigeration effect (NRE), as it doesn't contribute to cooli...

Ed Janowiak joins the podcast to introduce us to ACCA Manual T. Compared to other manuals, Manual T is one of the least-considered ACCA manuals. However, it's the manual that advises us on how not to blow high-velocity air on people and has maintained the same standards since the mid-1900s. Unlike Manuals J, S, and D, Manual T is not recognized in code compliance. Manual T deals with air distribut...

In this short podcast, Bryan explains what the net refrigeration effect (NRE) is and how it affects HVAC systems. The net refrigeration effect (NRE) is what happens in the evaporator coil. The evaporator is the heat absorber; as air passes over the coil, the cooler refrigerant within the evaporator absorbs that heat and boils. The NRE is the net energy change that occurs during that process. You c...

Eric Kaiser returns to the podcast to talk about how we can use systems thinking to approach gas appliances and combustion in HVAC installation and service. Gas lines can be made of a few different materials, including black iron, copper, and CSST. These all have benefits, setbacks, and appropriate applications. For example, copper is common in propane (LP) systems but not natural gas. In coastal...

Some admins from the HVAC School Facebook group join the podcast to discuss the art of moderating a successful community. Bryan is joined by Eric Kaiser, Ty Branaman, Michael Housh, and Neil Comparetto. A community based on a skilled trade gives people an inviting space to share information and ask questions. It's also a space that allows people to practice how they present information. Groups als...

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. Overa...

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 wh...

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 s...

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...

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...

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 th...

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. Whil...

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...

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 larg...

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 f...

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....

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 fel...

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...

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...

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 th...

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 stat...

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 calculatio...

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...