HVAC School - For Techs, By Techs

In today’s short podcast, Bryan discusses buck-boost (auto) transformers and what they do. Autotransformers are not automatic; the “auto” prefix comes from the fact that autotransformers only have one inductive winding. That winding is shared by the primary and the secondary, so it is not an isolation-type transformer. These transformers run current through the same winding used for induction. Buck-boost transformers rise or decrease voltage. When the transformer “bucks,” it decreases voltage from primary to secondary, and a “boost” increases the voltage from primary to secondary. In other words, a “boost” is a step up, and a “buck” is a step down on a small scale. You can only wire these transformers if you use the manufacturer literature. There are many types of autotransformers, and you need to know the exact setup for your transformer’s specific design. Generic diagrams will usually not suffice. When sizing a buck-boost transformer, you must keep your start load in mind as well. As technicians, we might not be able to handle the specifics of sizing based on the start load, but it’s still something to keep in mind. The “buck” configuration of the buck-boost transformer is especially helpful in markets where the utility company tends to produce overvoltage. Our specific setup uses the Micron J750A1EB1A02, which you can learn more about on YouTube HERE. The “boost” configuration helps when a motor doesn’t get enough voltage from the utility source. Before you buck or boost the voltage, remember to account for both sides of the equation; if the utility changes the voltage, you still want to be within range. Bryan also covers: Ratings Current and capacity changes based on voltage Inverter-driven technology Voltage monitors (ICM493)   You can learn more about the 2022 HVACR Training Symposium HERE. If you have an iPhone, subscribe to our podcast HERE, and if you have an Android phone, subscribe HERE.

In today’s podcast, John Ellis joins Bryan to talk about indoor air quality (IAQ). He also explains the ideal process for providing IAQ solutions. John has a lot of experience working as a consultant for people who have respiratory issues, so he has valuable perspectives. The HVAC and IAQ fields intersect in the areas of thermal comfort, humidity, building pressures, ventilation, filtration, and source control (which pollutants are present, where they come from, and how we can remove them). John does not believe in throwing IAQ products at a problem. He believes in a thorough analysis of the structure to present the customer with solutions tailored to their home and needs. Ideally, John would like to see technicians take a process-oriented approach to indoor air quality: investigate, analyze, and quote. He believes in the power of slow, complete diagnosis, including listening to customers’ complaints. Remember, they’ve been living in the structure and can tell you about the issues they’ve noticed in their home and their health concerns. When you analyze a system, you may have to do additional testing beyond a visual inspection. Sometimes, you can’t always find fungal growth or must call an expert to test for asbestos. The key to practicing IAQ is to be open-minded and seek help from experts beyond your field. While IAQ solutions can be expensive, they can be well worth it for many customers. Try not to pass your own judgment on the prices; after all, you are performing quality work and could save your customer money on medical bills. John also explains: How to start training for IAQ sales Customer questionnaires Maintenance agreements Becoming comfortable with IAQ diagnostics How to present high costs and financing options to customers Being a truly caring, attentive consultant IAQ marketing Making money as an IAQ consultant   If you want to talk to John about IAQ, you can contact him at (505)-652-8119 or dynamicairconsulting@aol.com. If you have an iPhone, subscribe to our podcast HERE, and if you have an Android phone, subscribe HERE. You can learn more about the 2022 HVACR Training Symposium HERE.

In today’s podcast, Scott Krasman from TZOA, Andrew Greaves, and Kaleb Saleeby join Bryan for a conversation about mental health in the trades. We have a greater awareness of mental health than we ever did before, and although some of us may make fun of the topic, it is something we should focus on as HVAC technicians and business owners. “Toxic” is a common buzzword these days, but it’s relevant here. A work environment with toxic traits will wear you down over time as you are exposed to disillusioned or selfish journeymen or senior techs at work who disregard your wellbeing and development. Sadly, these behaviors often come from low morale and projection. HVAC industry leaders can take strides by promoting a culture of inclusiveness and encouraging conversations about mental health. There is also an element of personal responsibility within techs to acknowledge if something is wrong and to have honest conversations with their leaders. As techs, we need to know when to ask for help if we need it. Leaders must also look at themselves and address their own mental health issues so that they don’t project their issues onto others. As techs, we need self-awareness and intentionality to address our mental health. We need to understand what’s going on with ourselves (even if we need to talk to mental health professionals) so that we can take steps to get the support we need. We also cover: Helping younger techs grow Growth and discomfort vs. abuse and suffering Training, communication culture, and workload What it means to be in a dark place and how to get out of it Opening up to others about our struggles Active recovery Relationship issues and addiction Self-diagnosis and misdiagnosis Executive functioning Technology for mental health Caring for your body   You can learn more about the 2022 HVACR Training Symposium HERE. If you have an iPhone, subscribe to our podcast HERE, and if you have an Android phone, subscribe HERE.

In today’s podcast, Jim Bergmann talks about troubleshooting the entire system. He takes a holistic approach to the art of troubleshooting, NOT just an equipment-centered one. According to NIST, the most common HVAC system problems are duct leakage, refrigerant undercharge, and oversized equipment (often for undersized ducts). Duct leakage heavily affects the envelope; the equipment only plays a part in conditioning a space. As such, you will want to seal up holes that lead to unconditioned spaces, such as behind the thermostat, to avoid creating negative pressure. When there is that negative pressure, especially close to the thermostat, the home could be at risk of over-cooling. We check that the filter is clean, but we rarely ever question if the filter is good enough for the home. If the filter does not do a good job of improving air quality, you may consider changing the filter type or reducing the air velocity. Even though we take temperature and pressure readings from the outdoor units, we sometimes fail to look for obvious non-equipment issues. Some yard cleanliness issues, such as vines or pet urine on the condenser, simply get overlooked. These issues may result in high head pressure and are usually more likely than refrigerant overcharge. Overall, many systems have issues that can be solved with solid visual inspections and corrective measures beyond the equipment, such as addressing duct leakiness. When you troubleshoot better, you bring in more revenue for the company and increase your likelihood of getting a raise while keeping your customers satisfied. Jim also covers: Energy penalties in most HVAC systems MeasureQuick and its limitations Impacts of duct leakage on a home What to check when cleaning condensate drains Cleaning evaporators and condensers Filter grilles HEPA filters and pressure drop Bad flex duct practices and sensible heat gain   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 today’s podcast, Steven Rogers joins Bryan to talk about measuring total system airflow. Fluid measurement is NOT restricted to liquids; a fluid is anything that flows, including liquids and gases. In HVAC, we deal with both of them, but airflow is strictly limited to the flow of gas. The airflow we experience in HVAC is exclusively turbulent flow, NOT truly laminar flow. Total system airflow is difficult to measure directly; we can use flow hoods, but they have their limitations, especially on systems that have multiple returns. So, we measure pressures that give us clues about the airflow tendencies. One of the most recognizable measurements is static pressure. Many factors can contribute to poor static pressure, including dirty filters and poorly designed supply and return plenums. All measurements that you use to calculate static pressure will require an average. You take readings at multiple points of the duct, so you need to calculate an average value, whether you’re using static pressure tips, a hot wire anemometer, or a vane anemometer. Measurements are also particularly difficult to take in the supply registers, as there are almost no runs of straight duct. Recently, the TrueFlow grid has come on the scene to make airflow measurement easier. The grid relies on torque and RPM data to determine the total system airflow. The TrueFlow grid slides in where the filter goes and measures the total system airflow. The grid works with an app that considers the system tonnage to let you know how good or bad the airflow is. Bryan and Steven also discuss: Bernoulli’s principle “Moving” CFM targets Flow hood limitations Laminar vs. turbulent flow Static pressure probes vs. pitot tubes TESP and fan charts Precision vs. typical manometer TrueFlow grid vs. filter restriction Water heater backdraft Depressurization and combustion air zone   Check out The Energy Conservatory’s Website HERE. You can also check out the TrueFlow grid on that site or at HERE. Check out our handy calculators HERE.

In today’s short podcast, Bryan explains how growth happens in an HVAC/R career. He also gives tips to get “unstuck” if you feel like you aren’t moving forward. You won’t move forward if you haven’t set a goal to move forward. Making a “vision board” helps you determine what matters in your life, and it helps you clarify what you’ll need to do in order to achieve your life goals. That way, you can use your career to help achieve those goals and see whose support you need. Having a growth mindset and a lifelong learning mindset is essential for success. The growth mindset will help you deal with the “growing pains” of advancement (such as occasional failures). People with positive attitudes also tend to see more possibilities for their future careers. On the other hand, negative people are likely to idle in their careers. You also want to surround yourself with people who will bring out your best. It’s great to be around people who challenge you, have positive outlooks, and are happy for you when you make progress. Moreover, you want to be the person who is authentically excited when other people succeed and do good work. Also, try not to burn bridges with others. To advance in your HVAC career specifically, develop your hands-on skills. Think about it this way: are you merely doing your job’s requirements, or are you working on yourself? Read through manuals and check out technical materials to become more literate with systems and do better work on them. Also, try to find a mentor who will help you grow. People skills are underrated in our industry but are critical for career advancement. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In today’s podcast, Bryan and a team of Mitsubishi Electric Trane HVAC US (METUS) managers (Mike Schaefer, Charles Miltiades, and Sly Grimm) discuss mini-split controls strategies. Some contractors misunderstand what mini-splits are. Mini-splits CAN be ductless, but not all of them are ductless. Mini-split systems also have handheld controls, but those are not the only control options for mini-splits. Mini-split controls also come in wi-fi, wall-mounted, and wired varieties. Another common misconception about mini-splits is that they do not work in the cold. While that used to be accurate, modern mini-splits can function well as heat pumps that integrate backup heat. That is especially when it is also tied into a ducted system. A lot of thought goes into sensor placement, and contractors have many options as to where they can be placed. You can put wireless sensors in discreet locations, such as under the air return in the basement. Lately, there has been a market shift towards a preference for multizone equipment, so the wireless controls help manage several units instead of just one; you can manage 30+ indoor units. In general, homeowners are becoming more tech-savvy and are beginning to prefer tying all of their HVAC systems together and managing them all via one platform. As such, Mitsubishi controls can connect to smart home assistants, such as Alexa or Google. Mitsubishi mini-split controls also work with a cloud service that remembers data. However, a strong wi-fi system is necessary for these controls. The Mitsubishi Electric team also covers: Third-party controls and backup heat Integrating with boilers for primary heat Control placement Multizone controls Smart devices and signal strength Innovative solutions   Learn more at mylinkdrive.com and METUS’s YouTube channel. Check out our handy calculators HERE.

In today’s short podcast, Bryan discusses the key factors for system performance WITHOUT doing a deep dive into system commissioning. “Performance” refers to system efficiency, capacity, air filtration/cleanliness, longevity, and the ability to match the latent and sensible loads of a space. System airflow is the main performance factor to consider. To determine proper airflow (CFM), consult Manuals S, J, and D to perform calculations. In general, the absolute lowest limit is around 275 CFM (in extreme dehumidification mode), and the highest limit should be around 525 CFM (in arid climates or at altitude). You can determine your CFM target after you set up your ECM motor in the design. Then, you can also check airflow indicators: total external static pressure and pressure drop across the filter. The best way to improve airflow is to reduce pressure drop across the filter and build a better return plenum. For improving overall system performance, make sure the ducts are appropriately sized. System charge is another important performance factor. There is a lot more to evaluating charge than checking the superheat and subcooling. If possible, it is a good idea to weigh the charge with a scale and see how it matches up with the line length. In terms of long-term performance, the condenser’s location and cleanliness are also vital. Overall, a condenser works best if you put it in a slightly shaded area or on the north/east side of a building. The outdoor unit should also have some clearance from bushes and walls. Make sure the condenser is positioned away from pool equipment, water softener discharge, and dryer vent discharge. The goal is to keep the outdoor unit corrosion-free and able to “breathe.”   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 today’s podcast, Trevor and Bryan discuss Copeland Scroll Compressor Multiples for Air Conditioning. “Multiples” refer to equipment setups with multiple compressors that have connected suction and discharge lines, so they resemble parallel rack refrigeration setups. Multiples typically come in tandem (2) or trio (3) sets. Compared to having a single giant compressor, multiples are more efficient, more reliable, and have the ability to keep running in case if there’s a compressor failure. As a result, we often use multiples in rooftop units, makeup air units, and chillers. When you’re working on multiples or troubleshooting multiples, it’s okay to have sight glasses that indicate different oil levels. If you shut the compressors down and restart them, they should equalize. If you have a single compressor failure on a set of multiples, then you may have to replace both compressors in a tandem set; the manufacturer does not make single replacements for some tandem models. So, you can check the Application Engineering (AE) bulletin to determine your replacement needs. Multiples may contain compressors of different sizes. Compressors of different sizes have different mass flow rates. In these cases, you would use a flow restrictor to balance the mass flow across the compressors. On the refrigerant management end, the Copeland Scroll multiples will generally benefit from a crankcase heater. Correct location and installation of the crankcase heater are critical for proper functioning in multiples, and you can find that information in the manufacturer literature. Sometimes, you may also need an accumulator if there is a risk of refrigerant migration. Bryan and Trevor also discuss: Individual vs. multiple compressor manuals Oil equalization lines Compressor clamping Variable speed motors and compressor variability Sweating and flow restrictors Maximum tilt Adding oil Torque values   Check out the AE-1430 bulletin HERE. Check out Emerson’s HVACR training HERE. Then, navigate to “Contractor Tool Box Talks with Emerson.” 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 today’s short podcast, Bryan clears up the differences between markup and profit margins in HVAC businesses. The number one mistake that people make in business is confusing markup and gross margin. For example, you can double the price of a $50-part and sell it for $100. That would be a 100% markup. However, your gross margin is NOT 100%; your gross margin is only 50%; you only made a 50% profit on the total sale.  In the same case you have above, you have a 50% cost of goods sold (COGS). COGS is the direct cost of the expenses you paid to sell your service or product. The opposite of COGS is overhead. Overhead includes anything that doesn’t directly bring money to your business (rent, utility bills, etc.). Let’s say that your overhead costs total $30. You only end up with $20 of net profit. Typically, 10-20% net profit is a good (if slightly idealistic) goal. Net profit can contribute to business growth if you put it into your business. For example, you can use that money for advertising, buying vans, and buying better tools. If you want to determine a 10-20% goal, DO NOT USE MARKUP. Instead, you need to divide by your COGS expenses. In the case of the $50-scenario, let’s say that our cost of goods sold is 60%, so that seems like a 40% markup. You would divide 50 by 0.6, and you would get $83.33. If you multiplied by markup (140% or 1.4), you would have gotten $70. You wouldn’t come close to your gross margin number using the markup method.    Learn more about Refrigeration Technologies HERE. Check out NAVAC HERE. Check out SpeedClean HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE.