HVAC School - For Techs, By Techs

In this short podcast episode, Bryan talks about locked compressors and hard starts. He explains what actually happens when a compressor locks and covers when and how to use hard starts appropriately. Locked compressors are compressors that trip on overload during startup; they're considered "locked" because the rotor doesn't turn inside the stator and generates heat instead. The overload opens, but the compressor shell typically does not heat up very much when the overload opens. When you have a locked compressor, you need to start investigating the root cause with a thorough visual inspection. Then, check the run capacitor. A hard start kit helps you get the equipment working, but we should make sure we've addressed underlying electrical issues or installation conditions before installing a hard start kit. If the unit is old, then we may use a hard start as a temporary solution until the customer can purchase a new unit. In any case, it's best to use a factory hard start if the system requires it, but it's okay to use an aftermarket hard start kit to get an old system to run. Hard start kits consist of a start capacitor in series with the start winding, which moves more current into the start winding and decreases the time it takes to start the compressor; lower current readings indicate a faster amperage drop, as most ammeters read timed average values. The potential relay needs to open to take the start capacitor out of the circuit so that we don't continuously apply additional current to the start winding, which hurts the compressor over time. The hard start kit is not a silver bullet that solves all problems, and we need to know when to use them and how to use them appropriately. Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24. 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.

Licensed mechanical engineer Tony Amadio joins the podcast to talk about residential exhaust codes and best practices. He also put together a presentation about the topic, which you can view at https://hvacrschool.com/exhaust. When choosing duct materials for residential exhaust, you will want to stick to sheet metal and mind the gauge; flex ductwork can easily be damaged and will rack up a high total equivalent length in a way that sheet metal will not. Exhaust air should always discharge outdoors, not into an attic or crawl space, and that air needs to be replaced by air entering the conditioned space; makeup air is the air we draw in to replace the exhausted air, and we need appropriate undercuts to make sure we're getting the right amount of makeup air. Domestic cooking exhaust may also come in a few different varieties, each of which has different code requirements (with downdrafts needing much more CFM per ASHRAE). Range hood shape is also important for capturing as many particles as possible, but makeup air kits are usually unnecessary (and could be more of a hassle than they're worth). When it comes to bathroom exhaust, the CFM requirements differ between residential and light commercial, as well as intermittent and continuous exhaust. Steam generators may also be present, and they require extra consideration. Tony and Bryan also cover: Tony's education and career background Discharging and terminating exhaust air Insect screens Makeup air in light commercial applications Clothing dryer vs. bathroom vents Ductless clothes dryers and condensate piping Home Ventilation Institute (HVI) guidelines Pressure imbalance in a structure Residential vs. light commercial bathroom exhaust Static pressure, blower sizing, and exhaust duct sizing You can ask Tony questions by email at [email protected]. Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24. 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.

Phil Barr and Nathan Orr join the podcast to talk about wiring refrigerated cases in commercial spaces, including convenience stores and supermarkets. Cases may be medium-temp (or high-temp, in some cases) or low-temp. Medium-temp cases can typically defrost on their own during the off cycle, and low-temp cases may have electric or hot-gas defrost to help get ice off the coil at set intervals. Each system has an evaporator (and fans), compressor, condenser, and metering device (often a TXV or EEV), and low-temp refrigeration may have anti-sweat heaters, EPRs, and other components to manage. Challenges arise when electricians don't understand the fundamentals of commercial refrigeration, especially as the electrical circuitry relates to the refrigeration circuit components. Time crunches also apply a lot of pressure to electricians and refrigeration technicians. Testing circuits, such as fans and lighting, or using circuit tracers are good ways to get an idea of how an existing system is wired. Labeling wires and breakers and keeping those labels or information in places where others can read them can help you and other electricians in the future. One of the most common issues happens when technicians or electricians refuse to test out their results to catch their mistakes before callbacks happen. Even seemingly small electrical issues, such as improper lighting, can cause costly losses if product spoils and cannot be sold. Phil, Nathan, and Bryan also cover: Changes in central and case control strategies over time Challenges with retrofits and remodels Central lighting controls Mistakes that can be made when labeling wires or breakers Working against the clock Terminal blocks, DIN rails, and connectors Making mistakes and the origin of animosity Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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 taught by Bryan: Things to Keep Out of the System. He covers some installation best practices along the way to keep contaminants and non-condensable gases out of the system. We want to keep air, water, dirt, copper shavings, solvents, and nitrogen out of an operating system. All we want in an operating system is the appropriate oil and refrigerant for the system. Unfortunately, the POE and PVE oil we mostly use in residential systems nowadays are very hygroscopic; they attract water, and POE mixes with water to form acid, another thing we want to keep out of the system. We can pull most of the moisture out of the system by pulling a deep vacuum and following the best practices for a fast and deep evacuation. However, we can also reduce the probability of moisture getting into the system in the first place by NOT working on copper while it's raining outside, sealing the copper tubing adequately when routing it underground or in a chase (a common installation practice in Florida), and insulating it properly. Dirt can easily get into the system when we're modifying piping, especially when adding fittings or reaming, but we can use nitrogen or line set cleaners to flush it out. Purging the lines and flowing nitrogen while brazing also help keep air and water vapor out of the copper lines. When deburring, try to avoid letting the burr or copper shavings from falling into the tubing. Bryan also covers: Drawbacks to running copper underground Oil return and miscibility with refrigerant Flowing nitrogen without a regulator Leak detection and nitrogen pressure testing Why we should ream or deburr copper to prevent leaks Being able to trust your equipment Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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 air changes per hour, also known as ACH, and what it means in HVAC design and indoor air quality (IAQ) discussions. ACH tells us how frequently the entire volume of air in a room or structure is replaced; we are referring to the cubic feet of air leaving a space and then being replaced within that same space. If we have a balanced number of cubic feet per minute (CFM) of air supplied to and returned from the room in one hour, we would multiply that CFM by 60 to get the ACH, as there are 60 minutes in one hour. ACH should not be used to calculate heat loss and heat gain, even though BTUs are moved with air. ACH is a practical guideline for HVAC design. Ventilation needs will vary based on the purpose of a room and the number of occupants in it, and ACH tends to be a more important factor for determining how we can meet ventilation needs in commercial and industrial structures than in residential structures, in which we mostly rely on Manual J calculations of sensible and latent BTU gains and losses. However, we should not confuse ACH with outdoor air ventilation requirements as described in ASHRAE Standards 62.1 and 62.2. ACH also comes into play when it comes to infiltration and the tightness of an entire structure. When used in the context of blower door testing, the ACH will tell us if a building meets tightness standards. There is also a term called ACH50, which refers to air changes per hour at the standard pressure for blower door testing: -50 Pascals. ACH50 does not reflect ACH under natural conditions (ACH natural). 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.

Roman Baugh joins the podcast to talk about oil return and the refrigerant charge in VRV systems. VRV systems—also known as variable refrigerant volume (or variable refrigerant flow/VRF) systems—have one outdoor unit, one or multiple compressors, and multiple indoor units. The outdoor unit modulates to meet the indoor units' fluctuating demands. They are versatile and flexible systems. Like parallel racks, VRV systems have long lines and a lot of piping, so oil return and refrigerant charge are especially critical. VRVs have specific control protocols, as they need refrigerant volume and velocity to move oil and keep it lubricating the compressor for its entire lifespan; oil return mode, the refrigerant charge, and the piping protocols are supposed to support that function. When it comes to piping protocols, line sizing is critical. Whenever there is a need to relocate the outdoor unit and change the piping configuration, the charge needs to be adjusted, and the piping may even need to be upsized to prevent restrictions from happening. Daikin has VRV WebXpress (and SplitXpress) software for equipment selection; the goal is to help installers out with the line length and charging whenever it needs to be changed. When trying to get the oil return and line sizing right, you ultimately need to look at the manufacturer's literature and resources. It also helps service technicians if the installer makes the charge and line information readily available to anyone who works on their VRV install in the future. Roman and Bryan also discuss: Where and how oil can settle in VRVs Consequences of improper charge in VRVs Liquid lines in VRVs Violating piping rules and safety protocols Vertical separation in liquid line sizing Suction line sizing POE and PVE oil miscibility Daikin's resources Check out daikincity.com to find Daikin's literature and software programs. 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 oxidation and all the buzz behind "magical air-cleaning oxides" and other similar IAQ products. Oxidation is the loss of electrons, and reduction is the gain of electrons; oxygen commonly loses electrons. Rusting is a common example of oxidation; it happens when iron and oxygen interact in air or water. Metals that are more likely to react with oxygen (or corrode) are "less noble" than more noble metals. Less-noble metals, known as anodes, are sometimes used sacrificially to prevent the oxidation of nobler base metals, known as cathodes. While iron oxidation results in corrosion, some IAQ products use the process to bind oxygen molecules to unwanted substances. The IAQ products that use oxidation use the natural tendency of oxygen to lose electrons when bonding with other molecules. Ozone is a common agent of these IAQ products because an ozone molecule is very unstable and has three oxygen atoms, meaning it combines with other molecules via oxidation; it stabilizes other unstable molecules. Ozone, however, also reacts similarly with cells in our respiratory system and can cause irritation. In our industry's efforts to reduce the negative effects of COVID-19 viruses, oxidation has generated a good deal of interest. Nowadays, some IAQ products use smaller amounts of ozone or use activated carbon to catch ozone before it enters the conditioned space. Many manufacturers that use oxidation as a strategy use other ion-based oxidizers, just not ozone. Some of these oxidizers can break pollutants into aldehydes and other chemicals that may harm our bodies. If you want to learn more, you can read Oxidizers and What It Has to Do With COVID-19. Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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 filtration and IAQ, especially as they relate to virus control. He also answers the age-old question: "Can filters capture viruses?" While it may seem like particle size matters when it comes to filter efficacy, filters are not nets that strain air particles and prevent pollutants from passing through. When we talk about particles, we tend to focus on ones that are 0.3 microns in diameter, which tend to be medium-sized particles. Viruses tend to be among the smallest particles that we aim to control when it comes to IAQ. Filter media are crisscrossed fibers that catch particles in different ways. Inertial impaction is one means of stopping particles from passing through; the initial impact stops the particles from passing through. Interception happens when particles graze filter fibers and get stuck. Electrostatic attraction relies on energy to attract and catch particles. Diffusion happens when smaller particles move more erratically due to Brownian motion and get caught in the filter media. Viruses are among those smaller particles. Smaller particles' erratic motion makes them more likely to collide with the filter media, so they aren't necessarily harder to catch. Higher MERV ratings are associated with higher capture efficiencies. HEPA filters surpass the MERV scale and have also been proven to filter viruses out of the air, but we rarely use true HEPA filtration in residential HVAC because they are too restrictive for total system airflow. We can use bypass HEPA filtration to filter the air without creating a massive restriction at the unit. Large filter-back returns with 2" filters can help catch more particles with a greater surface area without tanking the static pressure. Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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.

Joey Henderson returns to the podcast to talk about heat pumps and inverters. The reversing valve, defrost cycles, and auxiliary heat can cause confusion for people who have primarily worked with furnaces or straight-cool A/C systems. Heat pumps use defrost cycles and bring on the auxiliary heat when the coil is ice-bound, which can present a challenge; we need to maintain cold coils without going into defrost all the time. Even though heat pumps were significantly less effective in years past, we will still see reduced performance in very cold conditions with the newer inverter-driven systems. Proper design, installation, and commissioning will also help occupants get the best performance out of their heat pumps. Inverters offer plenty of advantages for the cooling aspect of heat pumps, too, especially when it comes to achieving longer runtimes for dehumidification. They can also float their coil temperature, much like how refrigeration systems can use floating suction or head pressure. Condensate assemblies absolutely must be run properly to prevent backed-up drains and other related problems. Liquid line sizing and proper commissioning are also especially crucial for ductless inverter-driven systems. Joey and Bryan also discuss: Heat pump training and the electrification initiative Balance point Defrost strategies and universal defrost boards Dual-fuel systems Heat pump stigmas Blower door testing in various climate zones Surge protection and voltage monitoring How inverters work Occupant lifestyles and latent loads Zoning and duct design for inverter-driven systems Critical charge Line length for ductless systems Check out Joey's training, social media, and contact information at https://joejoehvac.com/. You can also check out Craig Migliaccio's book about mini-splits at https://www.acservicetech.com/mini-split-book. Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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.

Joey Henderson joins the podcast to talk about airflow and how we can get air where it needs to go. Duct design is one of the subjects that fuel Joey's passion for HVAC. In many cases, people focus too heavily on the equipment when diagnosing airflow problems; sometimes, the equipment simply can't perform as it should due to a poorly designed duct system. In residential HVAC, many duct systems aren't adequately planned out, and the airflow can't overcome restrictions like filters. We also need to keep in mind that flex ducts need to be as straight and tight as possible, and it's usually best if we slightly upsize them (compared to sheet metal). Even though balancing dampers aim to solve airflow problems, they often lead to other issues when installed and used incorrectly. In many cases, proper duct design would solve problems without the need for balancing dampers. Bypass dampers are also commonly misapplied. Some technicians also aren't properly trained to position their static pressure probes appropriately to measure total external static pressure, which leads to faulty readings and misinformed diagnoses. We can start by looking at things that can improve system performance at the equipment, like filtration; we can think of the equipment as the heart and the duct system as arteries (with static pressure as blood pressure), and the equipment also has the biggest pressure drop. Joey and Bryan also discuss: Joey's HVAC beginnings in the Navy and current work in education Educators' unique communication styles Learning from other educators as an educator Plenum boxes and turbulence Using wye fittings Laminar flow Modifying existing duct systems Motors and amp draw Building duct transitions Clients and money limitations Communicating with customers about airflow issues Ethics around duct design Unique duct challenges with inverter-driven systems Check out Joey's training, social media, and contact information at https://joejoehvac.com/. Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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 episode contains some of the questions and topics from the Business Round Table at the 4th Annual HVACR Training Symposium. Panelists include Tersh Blissett, Luke Peterson, and Andy Holt. One of the most critical parts of HVAC business ownership is knowing when to grow your business (i.e., hiring more techs and incorporating standalone maintenance and install departments). Ultimately, we need to think about how many service calls we're assigning to each technician per day and how many customers we have to turn down due to a busy schedule. Getting family members involved in the business can also have a range of positive and negative effects on a business. Delegating is another important skill that can help you run an HVAC business smoothly and focus on ownership and management over your day-to-day tasks. You need to understand your business's core processes but can delegate tasks that take time away from developing your business. When it comes to economic issues like inflation, we need to be looking at our own costs and competitors' costs to set our prices and pay our employees appropriately for the economic climate. We can use indicators like the consumer price index to assist with pricing and setting pay rates. Tersh, Luke, Andy, and Bryan also discuss: Key performance indicators (KPIs) Maintenance agreement frequency Talent acquisition vs. vetting Attracting vs. poaching employees Merit-based raises vs. cost-of-living raises Working "in" the business vs. working "on" the business Hiring people to handle day-to-day tasks Using Loom or similar video instruction software Support systems in your interpersonal relationships Motivation for starting a business Starting a business from scratch vs. acquisitions Explaining the difference between bids and online retail prices Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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 goes over some information about cap tubes (capillary tubes) and flow facts. Cap tubes are metering devices; they're long tubes with small diameters, and their flow rates are dictated by the tubing diameter size and tube length. Pistons and TXVs are some of the most common metering devices in residential HVAC, and flow restriction doesn't just happen at the metering device; distributors also contribute to the pressure drop and act like small capillary tubes in addition to the metering device. Older units, simple refrigerators, and window units are more likely to have capillary tubes as metering devices, as cap tubes are an easy and versatile use of small-gauge tubing. The diameter is the primary factor that influences the flow rate, and length is usually secondary. However, longer tubes cause the fluids to encounter more resistance (in the form of friction) as they flow from one end of the tube to the other; the longer the tube, the lower the flow rate. Longer tubes also cause the fluid velocity to decrease more than a short tube. When you have long runs of small-diameter tubing, you can replace a few sections with larger-diameter tubing to improve the flow rate. Sometimes, the ends of cap tubes are in hard-to-reach places, so replacing middle sections with larger-diameter tubing will still help decrease the static pressure and friction in the tubing. Oil traps and risers may be smaller than other areas of tubing, and they have a larger pressure drop and more friction associated with them. (However, the smaller tubing also increases the fluid velocity.) The same principle applies to 1/4" vs. larger-diameter vacuum hoses. Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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 and Jim Hagl from Copeland join the podcast to talk about filter driers and system cleanup. Filter driers come in many types and sizes; they typically go on the liquid line (bi-flow filter driers are used on heat pumps), but suction line filter driers also exist. Copeland's liquid line filter drier models include the EK (premium), BSL (smaller diameter), BOK (with HH desiccant to assist with burnout cleanup), and CU (copper spun). Bi-flow filter driers in Copeland's lineup include the BFK and BSB categories. These liquid line filter driers protect the metering device and should typically be installed as close to the metering device as possible (with some exceptions for heat pump startups in heating mode). These filter driers typically need to be replaced anytime the system is opened for service, the pressure drop across the drier exceeds 3 PSI, or the system is wet. Suction line filter driers in Copeland's lineup include the ASD, SFD, and CSFD models, all of which come in different shapes and sizes for varying applications. The ASK suction line filter drier has activated carbon to assist with burnout cleanup. When used to assist with contamination cleanup, suction line filter driers must be taken out of the system within a few days. Jim F., Jim H., and Bryan also discuss: Copeland and Emerson brand realignment Filtration data Myths about smaller-diameter filter driers Copper-spun drier uses and applications Ideal vs. accessible suction filter drier placement Desiccant considerations Filter drier selection best practices Moisture indicators Restricted filter driers Filter drier sizing and system charge Bi-flow driers in straight-cool systems Dealing with factory-installed filter driers Product names and suffixes Burnouts and oil Flowing nitrogen while brazing Additives and flushes Check out Copeland's filter driers at https://hvacrschool.com/copeland-driers. Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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 episode, Bryan goes over the fourth chapter of his new book, Unconformed. The chapter is called "So... What Do You Do?" Parents always want to be proud of their children, but it seems as though children are more proud of children who attend college than take up apprenticeships. However, these feelings largely seep in due to peer expectations; we want our children to measure up to our friends' standards or success, not necessarily our own. Parents are also less likely to encourage their children to get into the trades and value the time and expertise of tradespeople. All jobs, even less prestigious jobs, matter and have a purpose. Society tends to devalue tradespeople and manual laborers, but those jobs do a great service to society. Nevertheless, the competitive drive between parents and our fear of failure makes us fall into these mindsets where we devalue manual labor. The media and family members also trap us in these expectations. Society runs on the ability of people to solve problems and innovate, which means that blue-collar work is necessary for society to function. Not to mention, popular media and DIY culture have also brought attention to the artistry of the skilled trades. These positive changes are important to the perception of blue-collar work, and we can accept (and encourage) a child's choice to find purpose in the skilled trades, not just blindly seek happiness. Bryan also covers: Networking Expectations vs. standards The pitfalls of happiness The merits of working with our hands You can purchase Unconformed on Amazon's website HERE. Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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 based on a Kalos meeting about pipefitting best practices, particularly in commercial refrigeration applications. It begins with a few words about quality workmanship by the Kalos founder and CEO, Robert Orr. Pipefitting consists of repairs and joining metals; when joining metals, we need to liquify the alloy and draw it into the joint via capillary action. When pipefitting, oxygen can present some problems by coating the inside of the pipe with oxides that can contaminate the system. We can reduce the likelihood of oxide formation by flowing nitrogen while brazing; purging nitrogen displaces the oxygen in the lines before brazing, and flowing keeps oxygen out during the brazing process. Tip selection will be based on the piping diameter; tips that are too small won't adequately heat the pipe, and tips that are too large will consume too much fuel. You'll also need to leak-check your torch tanks and ensure that you have the appropriate ratio of oxygen to acetylene by aiming for a neutral flame rather than a carburizing or oxidizing flame. After brazing, we need to perform a nitrogen pressure test to ensure that the system is leak-free. Then, once the pressure test is passed, we should evacuate the system to keep the system clean, dry, and tight. Bryan, Matthew, Roman, and Nathan also cover: Brazing vs. soldering Properties of base metals Alloy properties and appropriate uses Mineral oil vs. POE oil and cupric oxide Safety practices and PPE Preparing copper (sealing, deburring, etc.) Valve seating Penetration and the gaps between surfaces Base metal temperature indications Advantages of nitrogen for pressure testing Vacuum pump best practices Micron gauges Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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 episode, Bryan talks about filter driers and their important role in HVAC/R system protection, especially in accordance with Copeland's (formerly Emerson's) AE24-1105 R5. We can really start keeping our systems contaminant-free by handling tubing properly, purging and flowing nitrogen, and keeping copper shavings out of the tubing when deburring or reaming. Suction and liquid filter driers protect the system during operation and are designed for specific purposes. We typically don't install suction filter driers in residential systems unless we're fixing a system with compressor burnout or acid contamination; in those cases, we also want to make sure we replace accumulators and clean out the line set as well as we possibly can. Commercial refrigeration tends to have more rigorous contamination prevention protocols, including testing oil for acid and installing suction filter driers in everyday operation, due to the use of multiple compressors in a single system. However, suction driers are recommended in ALL applications per AE24-1105. In many cases, we don't install them in systems because they can create a significant pressure drop in the suction line and damage the compressor, but suction filter driers can provide a net positive effect if we monitor them. We should install suction filter driers as close to the compressor(s) as possible, and we should cut them out when we need to remove them, not unsweat them. Bryan also covers: Liquid line filter drier placement Pressure drop across filter driers and replacement thresholds Burnout cleanup procedures Filter drier sizing Refrigerant additives Motor burnout in hermetic refrigerant-cooled compressors Electrical best practices For more information about filter drier selection by model number, visit https://hvacrschool.com/copeland-driers. Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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 episode is one of Alex Meaney's HVACR Training Symposium presentations: HVAC Design Backwards, Forwards, and In Between. Load calculation factors in all three means of heat transfer: conduction, convection, and radiation. It doesn't directly tell you the tonnage; it just tells you how many BTUs (sensible and latent) are entering or leaving a structure. When designing systems after doing load calculations, we need to be mindful of industry standards and their pitfalls, as well as the climate conditions and the difficulty of obtaining manufacturer data. Equipment selection by tonnage is only part of the picture when it comes to HVAC design; we also need to factor in airflow and duct design, especially duct sizing. However, many rules of thumb and poorly explained terms are counterproductive to a thorough understanding of HVAC design. In some cases, the best way to design a system may seem "backward," especially when starting with blower selection instead of ductwork. Duct design is particularly difficult, especially when software identifies several problems with designs that seemed to look good on paper. However, the software points out areas where you can adjust the duct size and manage restrictions to allow the fan to do its job without being derated by friction. Alex also covers: Insulation and efficiency ratings CLTD Groups Tricky radiant gains and losses The relationship between BTUs and tons AHRI ratings Shortcomings of Ductulators in duct design education Pressure vs. friction in ductwork Static pressure vs. velocity pressure Measuring friction with pressure Regulations vs. reality Furnace static pressure range Differences between commercial and residential duct design Oversized and under-ducted systems Variable-capacity systems ACCA manuals and tables Check out Alex Meaney's consultation business at https://www.meanhvac.com/. Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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 the Santa Fe Panel from the 4th Annual HVACR Training Symposium. The panel focused on dehumidification, was moderated by Nikki Krueger, and featured Andy Ask and Ken Gehring. "Matchmaking" a residence to the climate requires us to design and install equipment that keeps occupants healthy and comfortable. HVAC contractors need to focus on the dew points, especially as they remain high at night and in the shoulder seasons. Humidity loads tend to hold steady (even peak dew points), while sensible loads increase and drop, making it difficult to control latent heat loads the same way we control sensible loads. The equipment will typically be less efficient if you focus on long runtimes to remove latent heat under partial load conditions and maintain 50% humidity. Dehumidifier efficiency is determined on a pint per kilowatt basis, but a constantly running dehumidifier will do its job a lot more efficiently than one that starts and stops regularly. The dehumidifier adds heat to the house and should only come on when the HVAC system is having trouble maintaining the desired humidity load; the dehumidifier has a reheat effect, but the HVAC system will need to deal with the increased heat load. When you add a whole-house dehumidifier, adding a fresh air ventilation component is highly recommended. Nikki, Ken, and Andy also cover: Infiltration and exfiltration Variable-speed technology and supplemental dehumidification Fresh air ventilation Air conditioner vs. dehumidifier latent heat removal Net zero HVAC, electrification, and decarbonization initiatives Air mixing in the ductwork Standalone dehumidifiers Vapor pressure and buoyancy Sizing for peak dehumidification loads Dehumidifier supply and return tie-ins Static pressure and "injection" dehumidification Fan cycling Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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 where to place the micron gauge during evacuation and how to think about micron gauge positioning. Evacuation (deep vacuum) doesn't remove solid contaminants, and vaporizing liquid water is a time-consuming process; its main purpose is to remove water vapor, air, and nitrogen gases from the HVAC/R system. When you pull down below 500 microns and hold that pressure, we can make sure we have a clean, dry, and tight (leak-free) system. As we started using R-410A and POE oil, water in the system became a much bigger issue than it was with mineral oil (it was never to have water in the system, but it breaks down POE oil). Before we start pulling a vacuum on the system, we need to attach our micron gauge to the pump while it's isolated to make sure the pump is working. A modern vacuum pump should pull down below 100 microns in 30-60 seconds; if your pump can't pull down to 100 microns in under a minute when isolated, then you'll want to change the oil (possibly multiple times). Be sure to change the oil regularly and store it properly. When you pull a vacuum on a system, you'll want to attach your micron gauge as far away from the pump as possible to get an accurate indicator of your vacuum. Use core remover tools to isolate the system and make sure the far side of the system is brought below 500 microns during evacuation. The time it takes to pull down a system and the time you'll hold the vacuum will depend on your application (residential vs. commercial). Check out Review of Vacuum for Service Engineers (revised by Jim Bergmann and Bryan Orr, 2020) at https://www.trutechtools.com/accutools-review-of-vacuum-for-service-engineers.html. Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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 joins the podcast to talk about his journey from resi tech to industry-leading refrigeration trainer. Brett is best known for his educational content, but he is also the manager of technical troubleshooting and training at CoolSys. The skills gap is widening, and CoolSys was inspired to create a solution to that problem. Brett's goal is to offer training that provides education and a sense of community all at once. Since he likes to keep his training simple and establish a solid foundation for his students, one of Brett's favorite training practices includes going over a system's P&ID diagram with his students before even looking at it. He focuses on classroom engagement and keeping trainees interested. Brett does regional training sessions and has written technical documentation to help technicians. As he has shifted from a field role to a full-time educator role, he has noticed that he has had more time at home. CoolSys focuses on commercial and industrial refrigeration, including system components, racks, and controls. The transition from residential HVAC to commercial HVAC and refrigeration requires an inquisitive mind and a drive to keep learning. Independent learners tend to do particularly well. There is an additional step that people will have to take when they move from fieldwork to education; communication skills and an ability to keep students engaged are crucial. Brett and Bryan also cover: CoolSys's training plans First lessons for refrigeration and HVAC trainees Keep It Simple, Stupid (KISS) in training New technologies and energy efficiency in CoolSys training Reading and independent learning The ever-changing nature of the HVAC/R trade Mentorship Practical skills and training CoolSys technical library Check out CoolSys at https://coolsys.com/ to learn about the company and some job opportunities. You can also email Brett at [email protected] or listen to the Advanced Refrigeration Podcast (YouTube channel: https://www.youtube.com/@advancedrefrigerationpodca9389). Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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 gets into some oil talk, covering some common refrigerant oil terms and types. Esterification is the process by which organic acid and alcohol come together to form polyolester (POE) oil and water. Hydrolysis refers to the decomposition of a substance when it comes into contact with water; when POE mixes with water, it will break down into esters, organic acids, and alcohol. Once POE oil undergoes hydrolysis, the process can't be reversed to get the same original oil. POE oil is also hygroscopic; hygroscopicity refers to the ability of the oil to absorb moisture. Miscibility refers to the ability of an oil to mix with refrigerant and be carried with it. In the context of refrigerant oil, "polar" refers to a molecular structure with an uneven distribution of electrons; oils with polar structures attract water molecules. Solubility refers to how well one compound can dissolve into another. Mineral oil is a product of the distillation of crude oil and was common in systems that used CFC and HCFC refrigerants. Mineral oil isn't as miscible with new refrigerants that lack a chlorine molecule. Alkylbenzene (AB) is a synthetic oil used in some commercial refrigeration systems that is compatible with mineral oil. Polyolester (POE) oil is one of the most common synthetic oils we use in systems that use HFC refrigerants; its main downside is its high hygroscopicity and tendency to undergo hydrolysis. Polyalkylene glycol (PAG) oil is common in automotive A/C systems (R-134A) and is more hygroscopic than POE oil but does not undergo hydrolysis. Polyvinyl ether (PVE) oil is used as an alternative to POE oil; it is more hygroscopic but does not undergo hydrolysis. Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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 using a megohmmeter on a scroll compressor (or "megging" a scroll). Scroll compressors are among the most common compressor types nowadays, and they come with their unique needs and best practices. You can't pump them down into vacuums (in many cases, you can't do that anyway due to internal protections), run them in a vacuum, or run a high-voltage megohmmeter or hipot test. Scroll compressors differ from reciprocating compressors. A scroll compressor's motor is located at the bottom of the compressor, meaning it is immersed in refrigerant and oil when the system is operating AND when it is off; when the compressor is off and cold, there is a chance that there will be liquid refrigerant at the bottom. Compared to reciprocating compressors, scrolls tend to have a more compact and balanced design, and there could be a higher risk of internal arcing due to the tighter electrical tolerances associated with the design. Many inexpensive megohmmeters will say that any measurement below 10-20 megohms indicates a short, but some scrolls will have acceptable readings as low as 0.5 megohms to ground; these readings will typically show up on the smaller kilohm scale. You must only use a megohmmeter to ground, not from winding to winding. Moisture contamination, metallic debris, and lubrication issues can also cause a lower ohm reading than acceptable, so it's best to have historic data and track readings over time to make a diagnosis. Many modern multimeters can help you determine if a compressor is shorted to ground; you don't necessarily need a megohmmeter. You may also read the following tech tip to learn more: https://hvacrschool.com/scroll-compressor-pump-down-megohm-test-fusite-plugs/ Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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.

Matt Bruner joins the podcast to talk about what it's really like being an HVAC creative. Matt is a young HVAC business owner who has recently written several HVAC School tech tips and pursued creative interests in the trade. Being creative in any industry or aspect of life requires us to be aware of what's around us and think deeply about how things can be better. Creativity requires us to channel our dissatisfaction into finding a solution, not just complaining, similar to how children channel boredom into projects. While the industry relies on processes and procedures to establish consistent standards, an over-reliance on processes can remove opportunities for HVAC professionals to be creative in their careers. However, creative solutions still need to be based on a solid understanding of the scientific and safety fundamentals of the trade. In many cases, processes get better when people are allowed to be creative and tweak existing models and ways of doing. There is plenty of room for creativity in the design and installation of residential HVAC systems. Common problems, including the need for dehumidification, require creative solutions from smart people in the trade. Solving these challenges is fun for creative-minded people, especially those who acknowledge that they don't have all the answers. The HVAC industry has so many jobs that require creativity through hands-on problem-solving. Matt and Bryan also discuss: How Matt ended up in the HVAC industry "Poor" creativity Institutional and self-imposed constraints AI and data models What it really means to "do things better" Unteaching and unlearning bad habits Asking the right questions Self-awareness The evolution of "the right way" of doing things Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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 TXVs and their impacts on energy efficiency ratings (EER and SEER). EER (Energy Efficiency Ratio) is calculated based on fixed conditions (an outdoor temperature of 95 degrees Fahrenheit and an inside temperature of 80 degrees with 50% RH). EER is a ratio of cooling-only capacity in BTUs per hour to the total electrical input in watts. SEER (Seasonal Energy Efficiency Ratio) is the ratio of an HVAC system's cooling output during a typical cooling season to the seasonal electrical input in watts. Both energy efficiency ratios use non-proportional units (BTUs to watts), but SEER is supposed to account for a wide set of conditions (even though the climates of regional markets can vary quite wildly). EER2 and SEER2 are new standards based on updated equipment testing protocols with more realistic static pressures. TXVs and EEVs can modulate to control the amount of refrigerant going into the evaporator coil. TXVs maintain a set superheat at the evaporator coil outlet, which it detects with a sensing bulb mounted to the suction line. These sorts of modulating metering devices can boost system efficiency by adjusting the amount of refrigerant it feeds into the evaporator coil. Underfeeding can lead to inefficiency, and overfeeding can cause system damage. Non-bleed TXVs shut tight once the compressor shuts off, which prevents refrigerant migration during the off cycle and pressure equalization, thus protecting the compressor and reducing the cyclic degradation coefficient. The compressor may have to start a little bit harder, but the effects of the hard shutoff can improve the SEER rating by about 0.5. TXV systems are, overall, more efficient than systems fixed-orifice metering devices. Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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 Ball from NCI joins the podcast to talk about high-performance maintenance contracts and agreements. A high-performance maintenance agreement requires you to take system measurements and present solutions to maximize performance accordingly and exceed customers' expectations, not just make assumptions about the performance parameters. Key measurements we should know include the charge levels, total external static pressure, filter & coil pressure drop, and CFM per ton. Many HVAC contractors and technicians don't really believe in maintenance procedures; some contractors merely want to keep customers or secure work during the shoulder months and don't aim to optimize the homeowners' systems. Maintenance procedures provide technicians and contractors the opportunity to improve the health and comfort of their customers. To perform a quality maintenance procedure, we need to establish company-wide processes that produce consistent results. When we standardize maintenance and installation procedures, we want to think about what an ideal system would look like and make our processes meet those expectations. Scheduling is an important aspect of maintenance agreements, and your ability to commit to a schedule can make or break your maintenance program. Pricing is also critical, and customers tend to be educated on their options; many of them understand that a higher price will often indicate higher standards. As we perfect our maintenance procedures and take advantage of technology, we can embrace monitoring in our maintenance programs. Jim and Bryan also discuss: Jim's history in the industry SEER ratings vs. real efficiency The value of historical measurements Craftsmanship and quality standards "Unteaching" poor practices Communication practices with customers Roleplay as a training tool Monitoring as the next step for high-performance maintenance programs Learn more about NCI and high-performance HVAC at https://nationalcomfortinstitute.com/. You can email Jim at [email protected] or call him at (440)-670-8783. Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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 episode of the HVAC School podcast Steve Coscia's symposium presentation: HVAC Soft Skill Training Resources. Likability is a superpower in any job that requires you to interface with customers or students. Every word and mannerism your customer or student sees will matter, and it's important to be likable. Those impressions can heavily influence their decision-making. Making a good first impression is one of the most important areas where we can focus our soft skills, and being on time is an easy way to make a good first impression on customers. When we are pleasant and convey mastery of our craft, we become more likely to earn appreciation and respect from customers and fellow tradespeople. Delegating the authority of the class is a soft skill that is important for instructors, as it encourages participation and lets a student be recognized by their peers. Telling a "signature" story, using props, and making the classroom interactive also help you convey useful information to your students and keep them interested. The objective is to get students to talk, and applying the "rule of 10" with these methods should help keep students' attention. Whether you're leading an employee meeting or training a class, don't be afraid to embrace your unique brand of teaching or leadership. Steve also covers: Lessons learned as a writer and instructor "Overpreparation" Humility Using action-oriented language and being honest Cleanliness and organization skills Sharing information with coworkers The Silo Effect Editorializing and saying too much Using proper grammar and positive words Congruency Integrity, self-control, and proactivity Buying time and convenience-oriented customers Learn more about Steve's training at https://www.coscia.com/, and be sure to check out his training series on ESCO Institute's HVACR Learning Network at https://hvacr.elearn.network/pages/coscia-communications. Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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.

Roman Baugh returns to the podcast to talk about the time he installed an A2L system and lived to tell the tale. Roman used most of his same R-410A tools to install the first A2L-based ductless mini-split in Florida. Flare blocks, wrenches, and torque wrenches will all stay the same; you just have to be sure that your vacuum pumps and recovery machines are rated for use on A2L refrigerants. A2L-based mini-splits use flared fittings with no brazing necessary; this is currently the A1 status quo. Purging and flowing with nitrogen will be required of A2L systems. Purging refers to a higher flow rate and flowing refers to a very low flow rate (2-5 standard cubic feet per hour). If a pipe may have refrigerant inside of it, we will need to cut the pipe with a copper cutter, not use a torch. You will need to store A2L refrigerant tanks upright and locked in your van. You'll want the tanks to avoid being banged around or struck by other objects in the van. Although A2Ls are non-toxic, they still displace oxygen if a valve opens. Bryan and Roman also discuss: "Mildly" or "slightly" flammable Purging vs. flowing nitrogen Deep evacuation Flammable substances in the automotive industry Will there be reverse-threaded connections? The ever-changing HVAC industry Lower charge amounts Resources: You can learn more about A2L refrigerants in general on the ESCO Institute e-learning network by checking out training courses at https://hvacr.elearn.network/. Check out Opteon's new A2L refrigerant, XL41 (R-454B), at https://hvacrschool.com/xl41. You can find Daikin's R-32 resources at https://www.r32reasons.com/. Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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 motor speed and other basic electrical topics as they relate to motors in HVAC equipment. In a typical single-phase PSC-type (induction-driven) motor, the speed is primarily determined by the electrical cycle rate, also known as the hertz. The hertz represents the speed at which the electrical current changes direction (positive to negative) per second; in the USA, that number is typically 60 hertz. Unless we're dealing with ECMs and VFD-driven motors, the motor speed will be partially influenced by the hertz or frequency as determined by the utility company or a generator. Motor speed is also determined by the number of magnetic poles in the motor. A motor doesn't make a complete revolution per cycle; a cycle only refers to the distance between two poles. The more poles we have, the shorter the distance needs to turn per cycle. A two-pole motor rotates all the way every cycle, resulting in 3600 RPM under no-slip conditions (synchronous speed). A four-pole motor has half the RPM, and an eight-pole motor has 1/4 of the RPM of a two-pole motor. Speed taps add winding resistance between run and common to create slip and slow the motor. A six-pole motor has 1200 RPM synchronous, but 1075 is the effective speed with slip factored in. Each speed has a different level of winding resistance, which slows the motor as you move from high to low; the lower-speed tap has higher resistance than high-speed taps. ECMs and VFD-driven systems convert the frequency and don't depend on the electrical frequency from the utility or generator. Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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 returns to the podcast to talk about growing in productivity and confidence as a tech to avoid feeling stuck in your career. They talk about personal development within your organization and in communities or training courses beyond your organization. Confidence and productivity work hand in hand, and techs can grow in both areas when they prioritize the one that matters most to them. In many cases, repetition helps build confidence, especially in the trades and other professions where you work with your hands. Scheduling is another strategy that improves your productivity, which can boost your confidence in the long run. As humans, we tend to fixate on fears and problems. We can build our confidence by reframing our fears, giving ourselves (and others) grace when we make errors, and focusing on building our skills to work through challenges. It's also important to find people in your organization who will uplift you, not hold you back. Developing unhealthy habits is a possible consequence of over-focusing on work, and it could be detrimental to your personal and professional life. Your physical and mental health are also important to your productivity and progress. Trevor and Bryan also discuss: Using a calendar to manage productivity Learning new skills to build confidence Communicating with your employer and building a relationship Training programs Self-assessment and going out of your comfort zone Caring about yourself to care about others Some of Bryan and Trevor's favorite books on the topic: Soundtracks by Jon Acuff Atomic Habits by James Clear Good to Great by Jim Collins Check out Trevor's Refrigeration Mentor program at https://refrigerationmentor.com/. Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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 episode is Alex Meaney's 2023 HVACR Training Symposium session: "The Art of Unteaching." We may have flawed understandings of HVAC concepts, including the understanding that "heat rises." Our world is constantly shaped by the things we see and believe, and we are hard-wired to defend our observations and beliefs if we feel that those are threatened by new information. Instructors need to be sneaky about "unteaching" flawed ways of understanding the scientific principles of HVAC. When we communicate concepts to others, we need to watch our language and make sure our messages are clear; the subtext is as important, if not more important, than the actual material. Humility also goes a long way when teaching, though teachers need to be especially careful of imposter syndrome. Teachers can be most effective when they find a point of common ground between what their students already know and what they want to teach their students; avoiding jargon is a good way to make sure everyone can start on the same page before you teach them the vocabulary. When teaching, think about filling in the gaps without students realizing that those gaps have been filled; some teaching techniques, like inversion, can help with this process. Group settings also make it easier for students to process new information. Alex also covers: Pitfalls of the 12,000-BTU rule Bridge vs. bedrock foundation Pedantism and cognitive dissonance Repeating and rephrasing answers The "forgot to know it" approach Humility and the "reset button" Fallacies and heuristics Being able to understand when you're wrong Check out Alex's design consultation work at https://www.meanhvac.com/. Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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 compression ratio and efficiency, particularly how floating or fixed suction and head pressure affect those things. Compression ratio (absolute head pressure divided by absolute suction pressure) closely correlates to efficiency in all sorts of compression-refrigeration HVAC/R systems; the most efficient systems have high mass flow with less compressor work. High compression ratios indicate a greater differential between the head and suction pressures. A lower compression ratio is desirable, but the number has to be realistic; a compression ratio of 1 indicates that the system is off. Medium-temp refrigeration compression ratios are typically around 3:1, whereas low-temp refrigeration can have higher compression ratios (6:1). In commercial refrigeration applications, we can help control the compression ratio with floating suction and head strategies. Floating the suction and head pressures allow the equipment to achieve lower compression ratios and higher equipment efficiency. Old strategies for controlling compression ratio would involve having a fixed evaporator temperature and suction pressure. In a parallel rack system, floating suction allows the suction pressure to float up when the case maintains temperature; this strategy helps close the gap between the absolute suction and absolute head pressures and reduces the compression ratio. Floating suction strategies allow the suction to "float" up by allowing the evaporator coil temperature to rise a little bit when the box temperature is under control. Floating head strategies, on the other hand, allow the head pressure to float down in low-ambient conditions. We can look at ambient temperature and discharge pressure to determine how much we can float down the head pressure. Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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 episode is Nikki Krueger (Santa Fe Dehumidifiers) and Bryan's 2023 HVACR Training Symposium session about how we can optimize dehumidification and efficiency to create an HVAC design and humidity utopia. While we attempt to achieve comfort and high indoor air quality in humid climates, we may find challenges integrating these with the HVAC system and getting customers to understand the need for proper dehumidification. Older homes that are built "leaky" allow for uncontrolled infiltration and exfiltration, but newer constructions are a lot tighter and rely on mechanical ventilation to control where the outdoor air comes from and make sure it is properly filtered and distributed. We deal with both sensible and latent BTUs in a home, and we can't treat them as though they're all equal. Many high-efficiency systems have high sensible heat ratios (SHRs) and are designed to remove sensible BTUs very efficiently, but they're not adequate at removing latent BTUs. Ideally, we would rely on an A/C system or heat pump to dehumidify the air in cooling mode before adding a dehumidifier. However, some of the systems that are best equipped to handle high latent loads will be less efficient. If you wish to install supplemental humidification, the ideal design will have a dedicated return and tie into the main HVAC supply duct. Nikki and Bryan also discuss: Willis Carrier's real invention Strategies for reducing conductive, convective, and radiant gains Understanding relative humidity and dew point Design loads Electrification and energy efficiency incentives Adiabatic heating and cooling Single-stage vs. multi-stage equipment Dehumidification for ductless mini-splits Supplemental dehumidifier designs Learn more about Santa Fe Dehumidifiers at https://www.santa-fe-products.com/. Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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 is the episode for you if you've ever asked, "What the flux?" In this short podcast, Bryan explains the basics of flux in soldering and brazing, as well as magnetism. Flux means "flow." In HVAC, "flux" may have two meanings. It may refer to the substance that helps the molten alloy flow and bond to base metals more effectively when you're soldering or brazing. However, flux may also refer to magnetic flux, which is the lines of force that emanate from a magnet; this concept is important in inductive loads like transformers. In soldering, brazing, and welding, flux is a powder-paste or liquid that you apply to the base metal. You usually apply it directly to the male side of the base metal, or it may be embedded in the brazing alloy. Flux prevents oxides (like rust or the black flakes, cupric oxide) from forming on the surface you're brazing, which commonly happens at higher temperatures. Flux helps you create a proper bond, but it doesn't eliminate the need to clean the base metal before brazing. You typically don't need flux when you use silver-phosphorus or phosphorus-copper brazing rods for copper-to-copper brazing; the phosphorus acts as a fluxing agent, and using flux may increase the risk of contamination. It's also important to remove the flux from the metal after brazing because it may cause pitting; you may use a brush and/or a wet rag. Flux is useful when you use rods with high silver content or when you have other base metals; the appropriate flux will depend on the base metal, especially if you're soldering aluminum. Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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) returns to the podcast to discuss the impacts of duct leakage on occupant comfort and HVAC system performance. Duct leakage has more significant negative effects in heat pump systems than in furnace systems, especially in climates with high heating, cooling, or latent loads, due to pressure imbalances and moisture problems. You can measure duct leakage by masking off all supply and return registers, attaching a calibrated fan, and running the duct blaster to pressurize the duct work to 25 Pascals. Exhaust-only ventilation presents many of the same problems as duct leakage, particularly in the humid South. The duct leakage allowable by code (in Florida) is almost equivalent to a 50-CFM bathroom fan. Leakage often happens on the supply side, and it is important to determine whether the leakage is happening on the supply or return side; you may lose significant capacity on the supply side, and you may lose a little less capacity if the leakage is primarily on the return side. That capacity, however, is often heavily latent, leading to potential moisture problems (though less so in cold climates). Duct leakage may go outside or merely into an unconditioned space within the home; you can test the duct leakage outside with a duct blaster and a blower door simultaneously. Steve and Bryan also discuss: Duct leakage problem differences in the North and South Regulations and their effects on changeout practices Using powered flow hoods and a TrueFlow grid to measure duct leakage Duct leakage allowable by code Home construction types and duct configuration Envelope leakage Leakage testing and pricing Low-Income Heating Assistance Program (LIHEAP) Learn more about TEC at https://energyconservatory.com/. Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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.

Tom Lorenz from Sensi joins the podcast to talk about the launch of the Sensi Touch 2 thermostat. The Sensi Touch 2 smart thermostat is compatible with room sensors, which makes it an efficient and effective thermostat. Smart thermostats are becoming more common in homes, especially as we focus on HVAC efficiency. Designers are aiming to make smart thermostats user-friendly, aesthetically pleasing, easy to install, and driven by data (via sensors). Installation is easy for contractors, as it relies on push terminals and cleanly covers up the previous thermostat's installation site. The Sensi Touch 2 requires a common wire, but it has easy-to-use push terminals that allow wires to click into place. It also has dedicated accessory terminals for add-on equipment like dehumidifiers. You can also pair the Sensi Touch 2 with its respective app to program the thermostat. Smart maintenance automatically alerts homeowners about poor performance or efficiency. These sorts of alerts can offer peace of mind for the homeowner. The room sensors allow the Sensi Touch 2 to manage home comfort by collecting data from several locations of the house; you can sync up to 15 room sensors to the Sensi Touch 2 thermostat. As with other Sensi thermostats, the Sensi Touch 2 has contractor branding capabilities. You can get your company name and number programmed into the main display so that the customers know who to call whenever they need something. You can learn more at procontractorbranding.com. Tom and Bryan also discuss: History of Emerson, White-Rodgers, and Sensi controls Personal data and privacy concerns with smart technology Smart thermostat design and aesthetics Energy Star certification Sensi Lite (coming soon) Warranty information Learn more about the Sensi Touch 2 at https://sensi.copeland.com/en-us/for-professionals/touch2-smart-thermostat. Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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.

Eugene Silberstein from ESCO Group returns to the podcast to discuss why and how to create an internal training program for your HVAC/R company. HVAC/R has so many niches, and information and practices are always evolving, so lifelong learning is necessary for the industry. In-house training is a form of education that can come with many benefits, including control over scheduling, building community within the organization, and convenience. However, creating an in-house training program also comes with many challenges, including time and money expenses. For an internal training program to work, there needs to be a clear commitment to lifelong education that is ingrained in the culture. That could include bringing in other educators, setting up mentorship programs, and partnering with local trade schools. Unlike an external training program, an in-house training program also allows you to tailor education to your technicians' goals and needs. A good in-house training program creates an environment of psychological safety; it allows trainees to ask questions without feeling singled out or judged. Some people who know topics well aren't the best trainers; trainers need to know how to teach others, which means understanding how the human mind works. Commitment is ultimately what makes or breaks an internal training program. If your trainees can see that you are investing in them consistently, they will be more likely to give and get the most out of the training program. Eugene and Bryan also discuss: The hunger and need for HVAC/R education Benefits and drawbacks of external training Using mistakes and callbacks as learning experiences Educators who make trainees feel safe Education, engagement, and entertainment Will technicians leave your company if you train them? Casual but deliberate training Learn more about ESCO Group's HVACR learning network at https://hvacr.elearn.network/. Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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 the times when subcooling is meaningless. It is important to understand subcooling fully before using it as a charging or diagnostic method, particularly in refrigeration systems. When we need to charge TXV systems in residential HVAC, many technicians rely on subcooling to set the charge. However, refrigeration systems don't quite work the same way; charging a refrigeration system by subcooling may lead you to overcharge the system. We take subcooling on the liquid line between the condenser and the metering device. The condenser takes superheated vapor and rejects heat. This process turns the superheated vapor refrigerant into a liquid-vapor mixture midway through and subcools the liquid refrigerant at the bottom of the condenser. That liquid "stacks" at the bottom of the condenser. Adding more refrigerant will cause more liquid refrigerant to stack up at the end of the condenser and increase subcooling. These conditions can cause an increase in head pressure. However, many refrigeration systems have receivers between the metering device and the condenser. Excess refrigerant gets stored in the receiver; it doesn't stack up in the condenser, and it doesn't contribute to additional subcooling. As the liquid line fills and the metering device restricts, the liquid goes into the receiver, not the condenser. Subcooling won't change much until the receiver is full, which is a major problem; receivers should only be up to 80% full, even when pumped down. So, we rely on sight glasses or receiver-level monitors to determine the charge, not subcooling. The goal is to keep the sight glass clear, meaning there is a full line of liquid going to the metering device. (However, sight glasses will also be clear when the system is off or empty.) Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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.

Craig M (AC Service Tech) returns to the podcast to talk about solving work-life imbalance, especially for HVAC/R technicians who have children and families of their own. Our actions tend to be driven by our priorities, which vary at different stages of our lives. Someone's work-life balance could also vary depending on different parts of the year. When we let the right people into our lives and are surrounded by supportive communities, we can reconfigure our personal and career trajectories to keep them in line with our priorities. To create a healthy work-life balance, we must be open to investing in others and letting others invest in us. "Balance" implies a constant state of evenness, but for people who work many hours, own a business, or have a family, their time may not be perfectly balanced at all times. That sort of variety presents a challenge, but it also presents opportunities for us to invite wise counsel and maintain communication to make sure we're on the same page as the important people in our lives. We are imperfect, and in many cases, we make mistakes when we do things we shouldn't do or fail to do things we should do. When we make those mistakes or bad things happen, we can think about practical measures we can immediately implement in our lives to make them more fulfilling in terms of our long-term vision. Craig and Bryan also discuss: Providing for one's family Seeking counsel and wisdom from others How lifestyles and priorities shift as children grow up Intentionality and short-term vs. long-term thinking Making the "right" decision Letting people struggle but supporting them Emotional maturity Authenticity Bringing positivity to communication and relationships Learn more about Craig's books and other educational resources at https://www.acservicetech.com/. Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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 how rules of thumb (ROT) can cause duct issues. He talks about the role of friction rate in duct design as well as its intent and limitations. Friction rate is a value located on duct calculation tools, including Ductulators. We use friction rate to predict the operating static pressure of the system, but it is often misapplied when people design their ductwork around rules of thumb. The friction rate is expressed in inches of water column ("WC), which we also use to measure static pressure. However, the operational static pressure and friction rate are NOT the same things. Ductulators provide information about friction rate based on 100 feet of straight ductwork in the size selected, which we almost never see in the field; fittings and turns add effective length (EL), so the total effective length (TEL) is often more than 100 feet. When duct designers apply rules of thumb, like a 0.1" friction rate, and apply it to the CFM, they don't consider the actual length of the duct. So, the ducts are often undersized and don't properly account for the actual resistance to airflow. If you want to stop using rules of thumb, ACCA Manual D and related software can help you get more precise design parameters and account for other restrictions. The following tech tips contain more information and specific equations to help you find the total effective length: The Friction Rate Chart (and What it Means), What the Heck is a Friction Rate? (Eric Kaiser), How to Determine the Friction Rate for Residential Duct Design (Neil Comparetto). Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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.

Craig Migliaccio (AC Service Tech) returns to the podcast to talk about what it means to have the heart of a teacher. Craig discovered his passion for teaching while instructing apprentices on the job, and he went into institutionalized teaching from there. He chose to overcome several administrative obstacles to become eligible as a teacher at technical schools, and that perseverance is one aspect of the "heart of a teacher." One of the most rewarding aspects of teaching is the investment in others. For Craig, HVAC is a tool for supporting someone's family, and a teacher can find a sense of purpose in helping people be better HVAC practitioners. When good teachers invest in their students or apprentices, they give those people a reason to take pride in their work. The job of a teacher isn't to give students the answer, which can be frustrating for students and the teachers of those frustrated students. People who have the heart of a teacher allow students to learn things themselves and be frustrated when they don't receive the answer immediately. Teachers ultimately care and want to keep improving, and they get their students to ask questions. The most important aspect of teaching is getting students to retain knowledge and build on it, and many students retain knowledge when they get to ask questions on their own and apply their knowledge. Craig and Bryan also discuss: Craig's experience with teaching licensure The intrinsic desire to share knowledge or skills Investing in others during a labor shortage Switching mindsets Monologuing vs. asking questions Continuous improvement as a teacher Impostor syndrome and teaching Making educational content more valuable Limitations of video/audio education Learn more about Craig's books and other educational resources at https://www.acservicetech.com/. Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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 explains why saturation can be CONFUSING and clears up some common misconceptions. Saturation applies to dehumidification and refrigerant inside the system. Generally, saturation is the state at which a substance can no longer hold or absorb any more of another substance. When air is saturated with water vapor and can hold no more, it is at the dew point or 100% relative humidity; it will condense on any surface below the air temperature. Air isn't like a sponge that absorbs water vapor; saturation deals with vapor pressure, particularly the pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases in a closed system. Dehumidification is the process by which we remove moisture from the air; this process improves comfort across a significant portion of North America during the summer months, and it prevents fungal growth inside the home. Air in a dehumidifier or an HVAC system in cool mode makes contact with a surface at a temperature below the dew point. So, moisture comes out of the air and condenses on the coil. Colder evaporator coils, which result from longer runtimes, are more effective at removing moisture. Inside a system, the refrigerant in the evaporator boils as it absorbs heat. The refrigerant can absorb a lot of heat due to the heat required to change state, also known as latent heat (compared to sensible heat, which is the heat required to raise the temperature of a substance). Until the refrigerant completely boils off, it is at saturation. Pressure also dictates the saturation point, and we use refrigerants that can boil under the appropriate temperature and pressure conditions for the HVAC equipment we're working with. Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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 from HAVEN returns to the podcast to talk about ventilation in humid climates and some best practices for working on systems that focus on the V in HVAC. HAVEN focuses on IAQ management with the use of software technology. HAVEN started off with its central air monitor, and the company then developed a central air controller to help customers make their homes healthier. Fresh-air ventilation is one IAQ, but humid climates make it tricky to bring that air in; dumping "fresh" air into the structure without taking extra precautions can lead to high indoor humidity and even microbial growth. ERVs, HRVs, and ventilating dehumidifiers are some traditional ventilation strategies for various climates; exhaust ventilation is also quite common but can pull hot, humid air through the building envelope. HAVEN is creating a more templated approach to ventilation; HAVEN uses whole-home in-duct monitoring and local weather data to get ideas of the conditions inside and outside the home to tailor fresh-air ventilation to each individual system's needs. HAVEN has partnered with several ventilating dehumidifier manufacturers, including Santa Fe and AprilAire; many of these manufacturers also use filtration to control the quality of incoming fresh air. Kevin and Bryan also discuss: HAVEN's journey during the COVID-19 pandemic Chemical interactions in our homes (VOCs and CO2) Exfiltration and infiltration The problem with industry standards and regulations Appropriate climates for ERVs, HRVs, and ventilating dehumidifiers Using dew point to control indoor and outdoor parameters Energy savings with HAVEN's technology Does a house need to "breathe?" HAVEN app You can learn more about HAVEN's offerings for HVAC professionals at https://pro.haveniaq.com/ and get a discount on HAVEN's product bundle at https://www.trutechtools.com/ by using the coupon code haven2022. Learn more about the 4th Annual HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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.

Dominick Guarino from NCI joins the podcast to talk about the High-Performance HVAC Summit, an upcoming event hosted by NCI from April 17–20. The National Comfort Institute (NCI) is a training organization that helps technicians learn crucial skills and succeed through high-performance contracting. High-performance contracting is based on the mindset of "don't just promise performance; prove it." To maximize technicians' potential, NCI teaches technicians how to test equipment properly and monetize their skills. Techs can then use their knowledge to teach the homeowner about the system and solve problems with sales; they can earn money while being solutions-oriented. NCI's High-Performance HVAC Summit is a training event geared toward HVAC business owners and contractors. It started as a membership conference for education and networking, and it has since expanded to include like-minded HVAC professionals from all walks of life. Workshops are led by a mix of contractors and NCI staff, and there are breakout sessions and other various session types. This year's High-Performance Summit theme will be "It All Starts With Service." The four focal points of the workshops will be lead generation through service and maintenance, CO safety, the lead handoff from service to sales, and maintenance agreements. One more session will focus on hands-on testing, called "Low-Performance Town" this year, and there will be a panel about the future of high-performance HVAC. Dominick and Bryan also discuss: Dominick and NCI's history in the industry High-performance maintenance Consumers who do their research The HVACR Training Symposium High-Performance Summit Awards Banquet NCI's collaboration with other industry leaders and organizations Visit https://www.gotosummit.com/ to learn more about the High-Performance Summit. If you decide to register for the summit, type HVACSCHOOL in the coupon code section for a $100 discount. Learn more about the 4th Annual HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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 from AHR 2023, Tony Gonzalez from Fieldpiece joins Bryan to talk about training, combustion, and more. Fieldpiece has a new combustion analyzer that reduces the cost of tool ownership and maximizes the tool's uptime, namely by using a long-lasting sensor. The combustion analyzer's oxygen and CO sensors seal up when the combustion analyzer is turned off, which pauses degradation. The sensors are also field-replaceable and come with a 4-year warranty. The CAT85 also has a built-in dual-port manometer (which can measure static pressure) and can measure a live draft pressure during combustion analysis. Some common misconceptions exist around combustion analyzer sensor lifespans and calibration. The sensor life refers to how long a sensor can output a signal to generate a reading; it doesn't refer to the accuracy of the sensor at the end of its life. Calibration keeps the sensors accurate, especially because sensor accuracy tends to degrade over time. To get the most out of your sensor, yearly calibration is recommended. Fieldpiece is also launching its ambassador program, which is a network of independent trainers with field knowledge who have been trained to become Fieldpiece product experts. Those ambassadors then train contractors and technicians on behalf of Fieldpiece. Tony and Bryan also discuss: Fieldpiece's sensor calibration process Water freezing in combustion analyzer traps Distinguishing your company from the competition with superior tools Technical training from Fieldpiece Fieldpiece leak detectors and new A2L refrigerants Infrared vs. heated diode leak detector sensors Learn more about Fieldpiece tools at https://www.fieldpiece.com/ or ask about training by emailing [email protected]. Learn more about the 4th Annual HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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 from AHR 2023, Brandon Marshall from Chemours and Chris Forth from JCI talk about the future of refrigerants and Opteon XL41 (R-454B). Refrigerant regulations are changing to pave the way for lower-GWP refrigerants, but M1 is also in full swing. M1 refers to the U.S. Department of Energy's implementation of the new efficiency standards for A/C units and heat pumps (SEER2, EER2, etc.). These standards changed the equipment testing procedure to match field conditions more closely. Opteon is the next-generation portfolio of low-GWP refrigerants for Chemours as a successor to the legacy refrigerants in the Freon product line. These refrigerants are a response to the HFC phasedown outlined in the AIM Act. JCI chose to use Opteon XL41, an HFO, for its equipment due to Opteon XL41's low GWP compared to R-32 and because of the similar operating pressures and temperatures to R-410A. A2Ls are a permanent change in the industry, and their safety considerations and best practices are here to stay. However, even though A2Ls are more flammable than A1 refrigerants, they are nowhere near as flammable as A3 refrigerants. Just about any refrigerant can propagate flame under the right conditions (including A1s), so A2Ls are only a little bit more flammable than those. Brandon, Chris, and Bryan also discuss: Brandon and Chris's industry experience The transition from CFCs to HCFCs to HFCs Refrigerant reclamation Upcoming GWP limits Hydrofluoroolefins (HFOs) A2L refrigerant product testing Staying up to date on A2L training resources Some of the prominent flammable refrigerant trainers Smuggled and counterfeit refrigerants Learn more about the 4th Annual HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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 from AHR 2023, Jim Bergmann and Joe Medosch talk about measureQuick and the ways it's EXPLODING with growth and new features. They also talk about heat pumps, electrification, and other hot topics in the industry. Jim Bergmann recently released an open letter about heat pumps on LinkedIn; he addressed the shortcomings of the industry from a skill standpoint. The lack of training and standards may be mitigated with proper training (and an understanding of building science fundamentals) or by embracing hybrid systems. Heat pumps may also perform relatively poorly during extreme weather events and may not manage temperature swings well. MeasureQuick has recently been working with ACCA and formed other partnerships to allow for standardization (for companies and the industry as a whole). More companies are also integrating with measureQuick, especially TEC and their TrueFlow Grid; accuracy across brands tends to be pretty consistent, and measureQuick allows you to mix and match tools. The customer-facing side of measureQuick has also received some development, which allows the customer to see the value and quality of their installation. MeasureQuick is keeping up with the growing pains by doing constant testing. Joe and Jim make sure the user experience is seamless, intuitive, and free of problems or inconveniences. Jim, Joe, and Bryan also discuss: Fixing the building envelope Heat pump vs. gas furnace comfort Energy Star certification for installations measureQuick user base milestones Industry leaders, supporters, and partnerships New measureQuick workflows Joe Medosch's role at measureQuick The challenges of the HVAC trade Technology challenges for measureQuick's users Free and paid measureQuick features Learn more about the 4th Annual HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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.

Genry Garcia returns to the podcast to talk about pressures in the building envelope, namely the infiltration skeletons behind closed doors. When doing load calculations (Manual J), we need to know how much of the heat load, especially the latent heat load, comes from leakage in the building envelope and the ducts. Opening/closing doors and windows can also worsen the issues that stem from infiltration due to upsetting the balance of pressures in the home. Smoke pencils and other similar tools can give you an idea of the pressure in a home and how it could change when doors open or close. Since there is a lot of room for inaccuracy in extreme climates (especially those with high latent loads), many HVAC systems are oversized and underperform. Some building design features also exacerbate problems presented by oversized HVAC systems. To get the data we need to design systems that mitigate those issues, we need to do a blower door test. Downsizing the tonnage in retrofits or replacements usually has advantages, but it must be done right, and customers may not always want to do that. It's the contractor's responsibility to give them a choice and educate them about the options and what the thorough diagnostic process looks like, including balancing the home and checking the pressure in relation to the outdoors. Genry and Bryan also discuss: Positive and negative pressure in certain rooms Exhaust ventilation and pressurization Using See Stack to see differences in loads Leaving the fan in the "on" position Useful tools Variables in lab-based testing and field testing Getting hung up on the 3 Pascals rule of thumb Leaky rooms vs. whole-home leakage Learn more about the 4th Annual HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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 episode recorded live at AHR Expo 2023, Nick from INFICON joins Bryan to talk about leak detectors and how we can improve our understanding of them. Some leak detectors, including the INFICON Stratus, measure concentrations in PPM (parts per million). When measuring PPM, we have to keep in mind that it doesn't indicate the size of the leak or leak rate, but it does help us pinpoint the leak location. In some cases, we also have to watch for automatic zeroing capabilities. Leak detectors come in many varieties, including heated-diode, ultrasonic, and infrared; each type has unique maintenance needs. Heated-diode leak detectors are sensitive, but their sensors wear off with frequent use and will require replacement. Infrared leak detectors use infrared absorption and don't degrade over time the way heated-diode leak detectors do. An ultrasonic leak detector picks up the sound of refrigerant and air leaking out of a hole to pinpoint the leak. It's a good idea to approach leak detection with a plan, including starting high on the coil and moving down (because refrigerant is heavier than air and may set off the leak detector below the actual leak). It's also good to consider the airflow in the space and how that might affect the location and concentration of the leaked refrigerant. Nick and Bryan also discuss: Pressure, hole shape, and leak rate Understanding tool maintenance Infrared leak detector usage and considerations Common causes of leak detector failure D-TEK product line CO2 and hydrocarbon sensors for leak detectors D-TEK Stratus modes (cloud hunting and pinpoint) Applications for D-TEK Stratus leak detectors "False" positives Learn more about INFICON at https://www.inficon.com/. Learn more about the 4th Annual HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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 episode recorded live at AHR Expo 2023, Dustin and Jim from Copeland/White-Rodgers join Bryan to talk about the use of heat pumps in cold climates. They talk about the history of heat pump innovation and talk about changes to come. Variable-speed and two-stage compressors, as well as advanced controls, make it easier for contractors to control sizing and for heat pumps to perform to acceptable standards in cooler climates. Contractors in cold climates also rely on dual-fuel models that use electric and gas heat, which makes it easier for the system to move the desired amount of heat. Variable-speed and two-stage compressors help the system deal with different heating and cooling capacities; in cooling mode, these technologies can also help with latent removal if the blower is also able to vary with the compressor. Advanced controls, especially universal controls, also help with defrost management, a key component of heat pump performance. When defrost is managed effectively, customers can yield energy savings. The White-Rodgers universal defrost control comes with coil and outdoor temperature sensors (thermistors) to determine when the unit is ice-bound; it also has a thermostat that can control second-stage heat. Dustin, Jim, and Bryan also discuss: Electrification and heat pump sales Vapor injection and compression ratio control Freq drives White-Rodgers universality and nomenclature Timed vs. demand defrost Electric heat vs. gas/oil heat costs WR Mobile app Multi-volt contactors (White-Rodgers SureSwitch) Pool heat pumps and contactors Crankcase heaters, long line sets, and total system charge A2L refrigerant testing Learn more about White-Rodgers products on the WR Mobile app, our partner page at https://hvacrschool.com/partner/emerson-white-rodgers/, or the website at https://climate.emerson.com/en-us/brands/white-rodgers. Learn more about the 4th Annual HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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 episode recorded live at AHR Expo 2023, Matthew Schlegel, the Commercial Product Manager of Ducted Systems from JCI (Johnson Controls) joins Bryan to talk about rooftop unit (RTU) retrofit facts and considerations. When doing an RTU retrofit, you want to make sure you know the budget before anything else; larger budgets will allow you to implement things like VFDs and even VAV technology. In many cases, you may consider adding an economizer for "free" cooling and energy savings. You also want to know what you will get out of a retrofit in terms of value, especially when it comes to system efficiency and longevity. Some common IAQ upgrades for RTUs include improved filtration, especially with MERV 13 filters. Economizers also allow you to control the amount of outside air with the help of an exhaust system or even barometric relief. UV lighting can also be used in light commercial RTUs. When doing a retrofit, you'll want to pay attention to the existing equipment's footprint. Sticking to that footprint will make the replacement aspect easier. The utility and electrical infrastructure are also important to consider, as you won't want to replace the existing piping, wiring, and connections. With regulations and technology constantly changing, it helps to be able to contact the manufacturer to assist with the retrofit process. Companies like JCI are trying to assist contractors with installations by providing guidance and education in the field. Matthew and Bryan also discuss: Matthew's professional experience at JCI Adding economizers and VFDs Convertible filter racks Cost-benefit analysis resources Changing regulations Interfacing with the manufacturer during the retrofitting process To learn more about JCI, visit https://www.johnsoncontrols.com/. Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium. 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.