Bryan Orr hosted a live podcast discussion all about 90% efficient furnaces with HVAC professionals Ty Branaman, Adam Mufich, and Matthew Bruner. They covered the basics of how 90% furnaces work compared to traditional 80% furnaces, troubleshooting tips, and best practices for installation and service. A key difference with 90% furnaces is the addition of a secondary heat exchanger that extracts more heat from the exhaust gases before they go out the flue. This allows the furnace to achieve at least 90% efficiency. The condensing of water vapor in the exhaust also releases latent heat. However, the acidic condensate must be properly drained, and pipes must be corrosion-resistant. Proper airflow is also critical. The experts emphasized starting any service job by carefully looking over the furnace and venting. Check for any signs of problems like leaks, debris buildup, or animals/pests blocking vents. Verify gas supply and use combustion analysis to optimize performance. When troubleshooting, methodically trace through the sequence of operations. Pressure switches, flame sensors, and airflow issues are common culprits. The podcast concludes with a reminder that extensive training content on HVAC topics like this is available through HVAC School and other industry experts. Continuing education and an open, collaborative mindset are important for professional growth. Key topics covered: How 90% furnaces achieve higher efficiency with a secondary heat exchanger Water condensation and corrosion concerns - importance of drainage and pipe material Verifying gas supply, venting, airflow, and using combustion analysis Troubleshooting tips - visually inspecting, tracing sequence of operations, checking pressure switches and flame sensor Proper installation positioning and intake/exhaust vent sizing per manufacturer specifications   View the entire livestream with Ty on our YouTube channel HERE. 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.” Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.  Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

In this short podcast, Bryan breaks down the differences between analog and digital sine waves. Analog readings deal with an unlimited number of values; they are very precise and can have any number of decimals. As a result, the alternating current (AC) analog sine readings have very smooth curves when we read them on an oscilloscope (in the US, we see 60 peak-and-valley cycles per second because the frequency is 60 hertz).  Variable frequency drives (VFDs) and ECMs work with digital outputs instead. The alternating current (AC) input is flattened out and then replicated as a direct current (DC) digital output that mimics an analog sine wave using technologies like pulse-width modulation (PWM). Digital outputs appear as a series of steps on an oscilloscope, but PWM doesn't output different "steps" of voltage. PWM just changes the length and frequency according to the duty cycle (percentage of the time energized or unenergized). Digital scrolls turn on and off very often, and the time they spend "on" is the duty cycle, which determines how it stages up and down. While ECM motor modules usually won't work with regular motors, VFDs can run with typical motors and modify sine waves. These sine waves don't have a smooth curve, but the digital waves can be smoothed out while voltage and current are modified. If VFD-driven motors aren't designed or shaft-grounded properly, electrical discharge machining (EDM) can happen with high-frequency voltage spikes, which can damage the shaft and bearings.   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.” Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.  Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

Bryan Orr interviews Tyler Nelson, an HVAC expert with over 20 years of experience as a contractor. They have an in-depth discussion about combustion analysis and why it is becoming increasingly important for HVAC technicians to utilize this process. The conversation provides an overview of combustion analysis benefits and why HVAC pros should incorporate it into their standard operating procedures. Tyler offers insightful perspectives from his decades of contracting experience, including his knowledge of how field conditions vary and factory settings may not translate perfectly. Carbon monoxide poses several dangers to customers and HVAC technicians. Tyler talks about CO poisoning risks and how analyzers can help detect issues. He also covers AHRI Guideline X for cracked heat exchanger testing and emphasizes the need to use combustion analyzers, not just visual inspection, to reliably detect cracks. Tyler also demonstrates the use of the Sauermann combustion analyzer and mobile app. He highlights key features like replaceable sensors, app control and reporting, and programming for optimum CO sensor protection. He details how combustion analysis allows you to optimize setup, monitor equipment health, and troubleshoot issues. Tyler and Bryan also discuss: Why combustion analysis is critical for proper HVAC system installation, maintenance, and diagnostics CO poisoning and risks to HVAC technicians AHRI Guideline X The role of combustion analysis in system commissioning, maintenance, and diagnostics Sauermann combustion analyzer and mobile app Advice for technicians to embrace innovations like analyzers while retaining old-school skills and knowledge   Read AHRI Guideline X in its entirety at https://www.ahrinet.org/search-standards/ahri-guideline-x-induced-draft-furnace-heat-exchanger-inspection.  Learn more about Sauermann tools at https://sauermanngroup.com/en-INT, and you can connect with Tyler on LinkedIn HERE. 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.” Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.  “Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

In this short podcast, Bryan talks about checking the charge of a heat pump in heat mode. This skill will become more critical as ambient temperatures get cooler. The most reliable way to check and set the charge regardless of operating mode and season is to weigh the charge. This method is most practical during installation and commissioning, and proper commissioning can prevent issues with charge levels later. Weighing the charge is recommended for big repairs, like major component replacements. But in many cases, we don't need to check the charge by hooking up gauges; we can check for proper operation by taking a few line temperature readings. Before carrying out any tests or taking readings, make sure the heat pump is defrosted and that you've carried out a full visual inspection. You can carry out a full delivered capacity test in either cooling or heating mode (without the electric heat strips energized) to determine how many BTUs the system is moving. Some simpler tests will require you to compare the discharge vapor line and suction line temperatures to the outdoor temperature and the liquid line temperature to the indoor temperature.  Manufacturers will give specific instructions for their units, including covering the condenser, and they may have charts to help you calculate system pressures based on indoor and outdoor temperatures. If you want to check suction pressure on the low side, you'll always use the common suction port, but you can take either discharge pressure or liquid pressure on the high side. Bryan also covers: Critical charge  Ductless system charging practices Some manufacturer-specific practices Indoor temperatures and system pressures R-22 rules of thumb Total discharge superheat Staging and capacity considerations Weighing out when in doubt   Read the tech tip about this topic at https://hvacrschool.com/checking-charge-heat-pump-winter/.  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. Subscribe to our YouTube channel at https://www.youtube.com/@HVACS. Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

Nikki Krueger and Genry Garcia return to the podcast to talk about a recent IAQ & dehumidification case study on a vintage home in Miami. The home was very clean but had a musty odor and VOC concerns. You can read the case study in the “Literature” section at https://www.santa-fe-products.com/about-us/media-resources/ or https://hvacrschool.com/case-study.  Blower door tests and ZPD revealed that the home was leaky, and the crawlspace was also not properly encapsulated. The options were to tighten the building and/or mitigate the problem by improving the HVAC system. The homeowners chose to improve the HVAC, which Genry did by installing a ventilating dehumidifier (Santa Fe Ultra98H), reducing system tonnage (3.5 to 2 tons), and putting in new ductwork. One of Genry’s key tips to address intermittent moisture issues is to pay attention to fluctuating pressures, not just under the blower door test conditions. Ongoing monitoring is crucial in these studies to measure the home under several different typical conditions. He also relies on blower door tests to determine if encapsulation is necessary or needs improvement, as insulation and encapsulation can bring new issues in their wake.  Extensive testing and working with other contractors (such as home insulators) are the best ways to get a solution that makes the homeowner happy. We need a holistic approach to design to achieve a homeowner’s IAQ and comfort goals, not necessarily following strict design guidelines to a T. Nikki, Genry, and Bryan also discuss: Zonal pressure diagnostics (ZPD) Dehumidifier ductwork Dehumidifier selection Attic encapsulation, condensation, and duct leakage MAD AIR The importance of IAQ case studies and the insights we can get from them Effects of insulation Dehumidifier performance in part-load conditions Mechanical equipment design Consulting the ACCA design manuals Maintaining equipment and sustaining positive results   Stay tuned for the companion tech tip. 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.

Skilled trades entrepreneur Tommy Mello joins the podcast to talk about creating a business where everyone wins: business owners, employees, vendors, AND customers. Tommy's main motivations in business are relationship-building and helping employees make a good living. Those motivations contribute to the development of company culture; even though cultures build themselves naturally, developing the right leaders will help build a positive company culture that values all employees equally. Tommy trains leaders to develop their strengths, shows them that they are valued, and gives them the resources they need to succeed. When companies grow, communication tools and project management technologies need to be standardized to help organize the company, including using checklists and SOPs. Departments also need to keep their focus on the company's main goal, not just the success of their division. The goal is to make sure that people are aware of their responsibilities early on and on board with the company's vision. To get the right people on board in the first place, we can improve our recruiting processes if we use social media to recruit talent—people who already have a job and are proven in their roles. Tommy also sees recruiting as a constant process that happens everywhere in the community and requires communication and follow-up. Tommy and Bryan also cover: Tommy's business: A1 Garage Doors Service Training leaders Allocating responsibilities and getting the right people on the bus Not punishing people for mistakes Unifying competition and collaboration Striking a balance of go-getting and humility Hiring for your weaknesses Tommy's new book, Elevate Building a legacy around serving others Seeing everyone as an individual instead of a representative Pricing and integrity   Check out Tommy's latest book, Elevate, at http://elevateandwin.com/. You can also learn more about his 2023 Freedom event in Orlando from Nov 1-3, 2023, at https://freedomevent.com/.  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.

Refrigeration Mentor Trevor Matthews returns to the podcast to share some of his tips for supermarket rack service. The supermarket refrigeration world is ripe with high-paying opportunities and uses similar skills that HVAC technicians use daily. Switching from HVAC to refrigeration will require a little bit more attention to some new components, especially controls and control systems. Technically-minded people tend to do well in the refrigeration field regardless of where they come from. When you're sent to a job site, you'll need to investigate the store and the case (where the refrigeration happens) before checking the controller and looking at the alarms and trends. As with HVAC, you'll want to start by looking for the obvious, like frozen drains. (Even though these systems are designed to freeze, we still need proper airflow and don't want standing water in the drains to freeze.) We don't want to go in there with our tools and start adjusting valves immediately. Attention to detail is critical in refrigeration. Getting familiar with the details of the equipment, especially by studying the P&IDs, will help you immensely. Being detailed in your service notes and logs will help you and anyone else who might work on the equipment; you can also keep a list of follow-up calls, which allows you to make proposals that bring value to your company, especially in the slower seasons, and prevents emergency service calls later. Trevor and Bryan also cover: The growth of Refrigeration Mentor Moving from an HVAC career to a refrigeration career Refrigeration dispatch procedure and tips Ice-bound coils, defrost, and freezing patterns Service procedures for common drains Band-aid fixes and re-commissioning equipment What to keep in a detailed log Quality vs. quantity of work Bringing value to your grocery refrigeration clients Positives and drawbacks of the refrigeration industry   Check out some of the great training Trevor offers through his Refrigeration Mentor program at https://refrigerationmentor.com/. You can also email Trevor 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.

In this short episode, Bryan covers traps, vents, and drains. He explains some common misconceptions and best practices for fabricating drains, especially in residential and light commercial structures in Florida. Cleanouts and vents are commonly confused with each other, and people often cap vents and leave cleanouts open. However, cleanouts (which must be capped) will always be before the trap, and vents come after the trap. When you have an indoor air handler, furnace, or fan coil, vents must be higher than the drain pan to allow the float switch to trip when the drain backs up. (Rooftop units have shorter vents.) Vents should stay open. We use static pressure to determine the trap depth, and the trap outlet must be shorter than the inlet. The best practice for drain pitch is to have 1/4" of fall for every foot of horizontal run, and we must avoid making double traps where air can get trapped between them. Vents prevent air bubbles from forming in drains with multiple traps. Double traps often form when drains are not supported properly and sag over time; using proper support in your installations is the best way to prevent that from happening.  In Florida, we often use only one trap and still get drainage. A typical installation has a cleanout, a trap, and a vent higher than the drain pan, all on a downward pitch. However, we also get severe condensation on our drains, and we must insulate the horizontal PVC runs to prevent sweating. In multi-family applications with common drains, each individual needs a trap and then a vent before the main drain.   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.

HAVEN IAQ founder and CEO Kevin Hart returns to the podcast to discuss cracking the home health comfort code, diving into IAQ’s illusory ideals. Even though the industry has been generating well-thought solutions to common problems, it’s difficult to put those solutions into practice on a large scale. As a result, it’s common to rely on selling “bolt-on” IAQ products, which don’t actually solve systemic IAQ problems. HAVEN’s recent work has also shown that only a few HVAC technicians are proactively offering IAQ solutions to homeowners; the vast majority wait for the owner to ask about a solution instead.  Some IAQ issues stem from duct and building envelope leakage, meaning technicians could offer to perform diagnostic tests (like blower door testing) and address the solution holistically with building envelope and duct sealing. However, not all customers are willing to pay for these, which is one of the biggest challenges of comfort consultations. The question about the real long-term, widespread effectiveness of comfort consults remains to be answered. Right now, we only have the illusion that IAQ problems are being solved. We might see positive changes to the state of IAQ if there is more forethought on the technician’s part to include diagnostic tests in their quotes when it makes sense to do so. Our industry may also see more proactivity in the quest to solve IAQ problems holistically by establishing sales goals and approaches. Kevin and Bryan also cover: Latest HAVEN IAQ developments The IAQ status quo Technicians and sales Evolution of evacuation best practices in the field Proactivity vs. reactivity when addressing IAQ problems IAQ solution goals and approaches The value of commissioning reports DIY and consumer-based IAQ solutions “Getting in the reps” when using diagnostic tools to solve problems The benefits and challenges of selling diagnostic services   Learn more about HAVEN at https://haveniaq.com/ or become a HAVEN Pro today at https://pro.haveniaq.com/. You can also contact Kevin directly 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.  

In this short podcast episode, Bryan goes over a few tubing insulation tips. Tubing insulation is also commonly known as Aeroflex, Armaflex, and Thermaflex—all brand names for black copper line set insulation. We typically have to insulate just the suction line in typical residential split HVAC systems, but you'll typically have to insulate both lines in ductless/VRV/VRF or refrigeration applications. The insulation should be on the tubing before brazing, gluing the ends together (only using a specialty tubing insulation adhesive, NOT duct tape!). Since these adhesives are types of contact cement, you will need to apply a thin coating on each side of the joint and wait for a few minutes before pushing the ends together. Some forms of tubing insulation are split and have an adhesive flap instead. Then, you'll want to hold the insulation back with a clamp about 8-10" away from the area where you're brazing to protect it from heat damage. When you finish brazing, you'll want to put the insulation back and make sure all necessary areas are covered. In cases where it's practical, especially in residential HVAC, pulling the insulation over the 90s and P-traps may be the best bet due to its smaller margins for error. However, mitered fittings may be required in larger systems. To assemble mitered fittings, use either a miter box or the template on the tubing insulation box. It's a good idea to use the disconnected tubing and make a mitered fitting on the bench as a template before making more—the tails can be a little long. Do NOT use the saw that comes with the miter kit—you will be fine with a very sharp knife that makes a smooth edge (and be safe!).   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.

Jim Fultz returns to the podcast to talk about the new HSI module from White-Rodgers, the 50E47U-843. You can learn more about this new universal HSI module at https://hvacrschool.com/hsimodule.  Hot surface ignition modules control the burner for gas appliances that use hot surface ignition, not just furnaces. Since the HSI module doesn't need to work with a blower fan, it can be used in water heaters, pool heaters, and many more appliances that don't primarily move air (except for combustion). It also controls the inducer blower and monitors the pressure switch. All White-Rodgers universal ignition modules work with the WR Connect app, which allows users to set up controls with a smartphone via NFC technology. The controls do not need to be powered on, and users do not need to be online during use. Users can also use the app to auto-configure their new White-Rodgers controls based on the old control settings. Technicians aren't required to use the app and can configure controls manually if desired. Universal controls that all operate similarly, like the White-Rodgers ignition modules, are great for creating a consistent workflow and establishing truck stock. In HVAC businesses and in the field, these modules are great for delivering efficiency and quality. The 50E47U-843 also shows real-time flame current, eliminating the need for technicians to wire flame sensors in series with their meter for testing. Jim and Bryan also cover: Emerson, Copeland, and White-Rodgers Hot surface ignition vs. other types of ignition Integrated furnace controls (IFCs) How near-field communication (NFC) technology works Fault codes Electrical inputs and outputs Local vs. remote flame sensing Integrated thermostat sensor for infrared and tube heaters WR Connect, WR Mobile, and Copeland Mobile apps   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.

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.