Hvac School - For Techs, By Techs

In today’s short podcast, Bryan discusses electric heat, how we use it in our work, and what it does.   Also called heat strips or heat elements, electric heat is a supplemental heat source that we usually see on heat pumps. We generally see them in fan coils within a cartridge or a kit at the top of an air handler. However, not all systems have backup heat.   We want to avoid running electric heat as much as possible because it is inefficient. There is almost nothing we can do to make heat strips more efficient; they will usually yield around 3.41 BTUs per watt.    We usually only run electric heat when a heating system can’t keep up with the heat loss. However, the electric heat often runs more often than it should, which can cause inefficient conditions. You can avoid inefficient conditions by programming the thermostat properly.   If you reduce the voltage on the heat strips, the less heat they will produce. Current ratings also differ between 208v or 240v applications. When you have more voltage, you’ll

Trevor Matthews comes on the podcast to discuss his newest project, Refrigeration Mentor. Refrigeration Mentor uses Trevor’s experience as a trainer and field technician to guide others in their careers.   Trevor’s goal is to help commercial refrigeration technicians grow and become more confident in their skills. He wants them to become the best technician they can be, and he believes that mentorship is one of the things that make our industry great. Mentorship can help people advance their careers, sharpen their skills, and ease their anxiety about work.   When we share knowledge, we bring value to the technicians. That value extends to the customer when technicians are more confident in their work and do better jobs. A good mentor has a commitment to doing quality work within the trade but will make their mentees feel comfortable to admit what they don’t know.   Mentors can also help their mentees develop a solid work-life balance that helps mentees be present to their jobs and their families. The mentor’s

In this podcast, Ben from HAVEN IAQ, Kaleb, and Bryan discuss how to control indoor air quality and take meaningful, accurate measurements.   HAVEN is a platform that offers hardware and software delivered to a homeowner through an HVAC professional. HAVEN’s goal is to give its customers a healthier, more comfortable home using IAQ solutions.    The hardware (controls, etc.) works with the HAVEN software to give customers and contractors data about IAQ and the performance of the HVAC equipment. Right now, you may install up to two HAVEN controllers and one monitor per zone to help control equipment and monitor the air content.    Air sampling occurs every hour, whether the HVAC system is running or not. Customers can learn to control their ventilation habits to address acute events (e.g., a spike in humidity from cooking), which only result in short-term IAQ problems. However, contractors can use the air sampling data to develop solutions for chronic events (e.g., constant high humidity).   Solutions, even si

Ryan Gorman comes on the podcast to discuss the differences between a college education and early career opportunities in the skilled trades.    Many parents feel pressured to send their children to college and encourage them to get a four-year degree. Despite what society may lead us to believe, there is no shame in thinking that college may not be suitable for you or your child; the skilled trades have many opportunities for people to learn throughout their lives and make a good living.   In many cases, parents may see college as “a ticket to the starting line.” Unfortunately, college tuition has skyrocketed over the years, and a good ROI is not guaranteed. Instead, a career in the skilled trades can allow a person to develop hard skills and land a well-paying job at a young age. As the skills gap widens, young people who learn skills make themselves attractive to employers and increase their earning potential.   Children and teenagers who want to become engineers may actually prefer a trades career where t

Jason Obrzut comes on the podcast to discuss A2L refrigerant facts. Jason is a member of AHRI’s Safe Refrigerant Transition Task Force and author of the RACT manual.   ASHRAE designates refrigerants into categories based on toxicity (A or B) and flammability (traditionally 1, 2, and 3). So, the new A2L designation indicates that a refrigerant is relatively non-toxic but has a flammability value between 1 (low) and 2 (moderate). While propane (R-290) is a good refrigerant because it is natural and has low toxicity, it is very flammable (A3).    Future refrigerants will likely fall under the A2L designation; the mild flammability will probably be the tradeoff for efficient, low-toxicity refrigerant with a low environmental impact. However, A2L refrigerants cannot be vented, even despite their low GWP. We also cannot use these refrigerants in retrofits.   A2L refrigerants will likely become much more prevalent around 2023 as HFC refrigerants phase down. The phase-down period will be specified shortly, and it wil

In today’s podcast, Bryan and some Kalos employees discuss how to deal with difficult bosses and coworkers in HVAC/R work.   Whether your coworkers have anger issues, are careless, or are miserable people, you don’t want that negativity to affect your job satisfaction. Addressing the behavior may likely help, but you don’t want to attack the other person. The key to dealing with difficult coworkers is to communicate boundaries respectfully with the goal of improving the work environment. Boundaries are also important when dealing with sarcastic people or those who make inappropriate remarks.   Any work environment with lots of people is bound to have cliques and tribes. You’re best off not getting involved in any of that drama; the best thing you can do is be kind whenever you have the opportunity. Nepotism may also fall under tribal behaviors, and it may cause you to rethink your future with a company.   On the leadership side, micromanagers can be frustrating—doubly so if your boss also happens to be condes

In today’s podcast, Ed Janowiak comes onto the podcast to talk about the ACCA manuals. Ed started off in the field and has recently become the new Manager of Design Education at ACCA. You can follow him on Snapchat (skinnyed).   ACCA (Air Conditioning Contractors of America) is responsible for publishing and setting the standards in all of the books we use for residential and light commercial HVAC work. (Residential work typically encompasses Manuals J, S, D, and T).   The manuals can be very math-heavy. Many software programs have come on the scene to help automate the math to some degree, but the manuals will still remain relevant for years to come. The ACCA manuals offer guidelines for predictable results, and much of a technician’s success will come down to how well they understand the order of operations.   In our trade, we have developed rules of thumb that help us with sizing and load calculations. However, those won’t work all the time, and the predictability element is lost. The ACCA manuals exist so

In today’s podcast, Bryan and Jesse talk about how technicians can talk about finances and money in the HVAC business.    The first step for any successful business is to provide customers/clients with a product or service of value. However, there must be a balance between providing something of value to customers and providing excellent customer service.   When starting an HVAC business, one of the biggest mistakes is making money the top priority. Money can only become a factor after a business establishes the value of its services and communicates its value to its customers. There is no hard line for fair pricing, so the contractor and customer must communicate to establish a price tag and the expectations for the work performed.    That same mistake applies to employees who want raises or promotions. Employees may feel as though they are owed more for their work, but they must establish their value before they get a raise. Again, the goal is to avoid unmet expectations.   Profitability and value are not j

In today’s short podcast, Bryan explains the differences between sleeve and ball bearings. Techs often make some avoidable mistakes because they either don’t know the difference between the two or don’t notice the bearing type on their equipment.   On a basic sensory level, ball bearings tend to be louder than sleeve bearings. So, if you replace a sleeve bearing motor with a ball bearing motor, then excess noise may not indicate any problems after all. Lubrication is usually more consistent with ball bearings, and those bearings have a far smaller contact area than sleeve bearings.   Sleeve bearings don’t usually last as long as ball bearings; they have a larger contact area and can burn out quickly, so they are more common on smaller equipment where they will experience less intense axial forces. Those sleeve bearings also aren’t as effective as ball bearings in variable-speed equipment. When techs put in a motor speed control and don’t pay attention to the bearing type, they may end up burning up the motor

In today’s podcast, Trevor Matthews from Emerson talks about horizontal scroll compressors. Throughout the podcast, we refer to Bulletin AE4-1338 (R3). You can find that bulletin HERE.   Horizontal scroll compressors are common in mobile applications, like buses and trains. They’re shorter in height than other compressors, so they fit into tighter spaces and are ideal for transport refrigeration.   Scroll compressors are particularly susceptible to overheating, and you need some controls to protect your compressor from damage. To prevent overheating, scroll compressors require pressure relief controls. You can typically use an OEM high-pressure control to protect the system. A low-pressure cutout installed in the suction line can help prevent TXV failure and a wide range of restrictions.   Accumulators are especially important for horizontal scrolls in heat-pump applications. However, accumulators have a fine mesh screen that can become clogged easily. So, we highly recommend replacing your accumulator in th

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, w

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 work as a consultant for people who have respiratory issues.   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.   W

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

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 somet

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 ti

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 mak

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 multiz

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 cha

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; 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. 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, you may have to replace both compressors in a tandem set; the manufacturer does not make single replacements for some tandem models. Check the Application Engineering (AE) bulletin to determi

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’re left 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,