HVAC School - For Techs, By Techs

In this short podcast, Bryan discusses the ever-controversial topic of indoor temperature in the summer. The old "20-degree rule" has come up many times, and it's time to put it to rest. Not to be confused with the 20-degree delta T rule, the 20-degree rule basically states that the home A/C system can only maintain temperatures up to 20 degrees below the outdoor temperature. For example, if the ambient temperature is 95°F, the indoor temperature should be able to stay around 75°F. However, that differential is not a fixed value. For example, if the outdoor temperature were to reach 105°F when the unit has 95° design conditions, the system capacity would decrease. The unit will not perform as expected, putting out fewer BTUs than it would under design conditions. Design conditions also account for latent load; that is why A/C systems in the arid Southwest USA can keep up with much hotter ambient temperatures than those in humid Florida. In Florida, we design for a higher latent load and must avoid oversizing; these conditions take away from designed equipment's sensible capacity. Correct sizing prevents short cycles and keeps humidity at bay. As it gets colder outside, an HVAC system will also have a lower heating capacity. Heat is a function of the temperature differential; heat may enter or leave the home via conduction (through walls) or radiation (through windows), and it will attempt to reach equilibrium. The only way to get around these heat gains and losses is to check the expanded performance data and perform load calculations (Manual J) to design the ideal system. You must design the equipment to maintain a specific differential under a standard set of conditions. Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Nathan Orr is back. In this podcast, we discuss suction pressure in market refrigeration and how rack techs think about it differently than HVAC. On parallel rack systems, suction temperature helps technicians determine the cooling load and how to get that to temperature. You run your discharge air temperature a bit lower than the product temperature. Your suction pressure also lets you know if your coil is reaching the correct temperature. Coil temp, also called suction saturation temperature (SST), is a vital metric for rack system operation. Lower suction pressure indicates a lower coil temperature or SST. The evaporator pressure regulating valves help control the evaporator pressure to manipulate the evaporator temperature. Compressors also help drive suction pressure, which is critical because racks may have several of them. When you walk into a rack room, you may see around five compressors. All suction lines tie into a single suction header (same goes for discharge and liquid lines and headers). Typically, the rack is constructed to maintain the SST even if a compressor goes down. When the SST no longer maintains, there will be a "rack down" call. If a case is not keeping temperature without an apparent rack issue, you want to take your superheat at the case to get an idea of the suction. The superheat, SST, and suction pressure will be your key indicators of problems, including defrost issues, clogged TXV strainers, and airflow problems. Overall, rack refrigeration systems work best with high suction pressure and low liquid pressure. Nathan and Bryan also discuss: TD in rack refrigeration Setting EPR valves Rack sizing "Rack down" calls Troubleshooting produce cases Holdback valves Frozen cases Using dry steam Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In this short podcast episode, Bryan explains why low static pressure may be bad. He also discusses the other indicators of airflow. When you look at fan charts, you'll notice that there will be an available static value. When you measure static pressure, you're looking for the pressure applied against the sides of the duct, not forward through the duct (velocity). Low static pressure is generally desirable because it indicates that the fan motor isn't working as hard to move the appropriate amount of air. In that same vein, slightly oversized ducts may be okay for these uses as well. However, low static is not always a good thing; you can only use it as an indicator for performance in standard operation. If the system is moving less air, then the static definitely WILL be lower. In normal operation, that may not be the case. You may also not be moving enough air, which can indicate an issue with the blower. In other words, you must be sure that the airflow is correct through other means than static pressure readings. Airflow has so many indicators, and using just one won't suffice. You'll also have to use your senses to listen for issues and familiarize yourself with the system operation; determining system airflow requires a multi-pronged approach. Bryan also discusses: Duct vs. face velocity Variable-speed equipment Thermostat calls and their effect on the blower Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Nathan and Bryan have a rollicking conversation about Nathan's transition from residential HVAC to market refrigeration. Nathan also covers what he has learned along the way. Hopefully, his experiences can help you decide if moving to market refrigeration may work for you. Before Nathan went into market refrigeration, he handled problem customers and repeat issues on the residential HVAC side. He worked on zoning systems and mini-splits quite often. Even in that time, he did minor work on supermarket projects if the team needed an extra person. Market refrigeration projects require full scopes of work and time constraints, complicate the transition from residential HVAC work. Market refrigeration primarily deals with rack systems. Rack refrigeration systems are different from residential HVAC systems because they require less of an understanding of heat transfer; refrigeration techs need more mechanical knowledge and may rely on many rules of thumb. Tactile skills are essential for refrigeration, but an understanding of the scientific fundamentals is less important. Although there are plenty of opportunities for increased profits in market refrigeration, the losses are also fast and harsh. The customer relationship is also perhaps even more important in market refrigeration because the service (and customer) options tend to be more limited. You may also expect to sacrifice more time due to the urgency of supermarket work. While you don't have to work yourself to death, you should definitely expect to have less time and to reschedule plans quite often if you make the transition to market refrigeration. Nathan and Bryan also discuss: Sight glasses vs. subcooling Cost of mistakes Acceptable vs. unacceptable outcomes for customers Overhiring vs. underhiring Rack replacement Difference in standards Replacing TXV parts Motors in refrigeration Hands-on skills and relevant professions Good and bad practices in refrigeration Working hours Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In this short podcast episode, Bryan covers pricing for HVAC/R parts and services; he explains how to come up with a fair price. To be able to price fairly, we need to understand what value and sacrifice look like. In the HVAC industry, we value hard work and growth in a way that some other people don't. We provide parts and labor and sell those in the free market, so we can control how much we charge for those. The price of a part means NOTHING in the industry. Instead, we primarily set prices based on labor, which is much more value-based. The customer has the right to accept or decline the service based on the price, and some customers WILL decline the service based on price. In the end, the customers can choose to agree or disagree with your opinion of value. Some people will object to the idea that customers know what a price is truly worth. However, Bryan is of the school of thought that almost no price is "unfair." As long as the customers have different companies to choose from, they have the right to shop around and pick a price that works for them. It is not the responsibility of the company to reduce its prices to attract customers. Remember, you need to think about pricing in terms of value and honesty; customers who also value your work will pay for it. If your services are superior, there is nothing wrong with keeping your prices high to reflect the value of your work. Bryan also covers: Learning about economics Supply and demand vs. price gouging Reinvesting in the business Sales vs. technical excellence Markup vs. gross margin Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

We talk with chemical and cleaning expert Ray Field on Legionnaires' disease. We discuss what it is, its history, and what we can do to prevent it proactively. Cooling towers host all kinds of microorganisms, including harmful bacteria like Legionella. Legionella is a natural bacteria that you can find in bodies of freshwater, including lakes, but it was discovered relatively recently, in the 1970s. We become susceptible to Legionnaires' disease when we inhale droplets that contain Legionella. Legionnaires' disease causes pneumonia-like symptoms and is potentially fatal. Cooling towers, unfortunately, provide perfect conditions for Legionella to survive and aerosolize. Decorative fountains and evaporative coolers also provide ideal conditions for Legionella to grow and thrive. Unsurprisingly, cleaning with special attention to microbe control helps mitigate Legionella bacteria growth. Bleach and anti-microbial peroxide help keep the water clean, but the bulk water is just one part of the system. When Legionella-filled water sprays beyond the tower, slime and water accumulations may also harbor Legionella. Inspecting and cleaning towers monthly are the best practices. Vacuum the basin and descale the tower each time you clean the tower; when you clean slime, deposits, and scale, you give Legionella fewer places to hide. You can also disinfect the tower exterior. Pressure-washing works well as a starting point and can be followed up with chemical technology. Overall, the key to preventing Legionnaires' disease is proactivity; safety begins with a regular maintenance regimen, use of proper PPE, and thorough training for cleaning procedures. Ray and Bryan also discuss: Legionella growth assistance History of Legionnaires' disease Ideal Legionella growth conditions ASHRAE Standard 188P Fill deposits Goodway products to combat Legionella Legionella testing and CDC guidelines Learn more about Goodway HERE. Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In this short podcast episode, Bryan covers ductless or mini-split cleaning. He collaborated with SpeedClean to map out this procedure and write a guide, which you can read HERE. Cleaning is ultimately a maintenance procedure, so one of the main goals is to keep energy efficiency high (watts per BTU). You can test energy efficiency by using two psychrometers: one up top and one going into the vanes. You can check the delta T and fan charts to determine the performance. Overall, you clean ductless units to improve system performance, equipment longevity, and indoor air quality. Be clean; wear shoe covers and put down drop cloths in the customer's home. First, you confirm the system operation and do a visual/auditory inspection. Then, make sure you have all of the PPE you need, especially goggles and gloves. Usually, you will clean the evaporator, blower wheel, air filters, and condenser coil. Pay attention to the drain and condensate pump as well; they can clog and negatively affect your system. We often use the bib kit indoors. When you use one of those bib kits, you can clean the evaporator (and sometimes the blower wheel) in place. The bib goes over the ductless unit, so cleaning is seamless and shouldn't make a mess as it runs off into a bucket. We recommend using a pump sprayer like the SpeedClean CoilJet; bringing a hose in can cause a mess and is impractical. When you've finished cleaning, make sure you let everything dry completely. We like to keep plenty of rags on us so that we can wipe everything down. After you think everything has dried, you can test the system. (It's a good idea to keep the bib on at first to prevent the unit from splashing liquid everywhere.) Learn more about SpeedClean HERE. Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Andrew Greaves comes on the podcast to give us a sneak peek into the life of a tool manufacturer. Andrew has worked in the field for a long time and has recently begun working for NAVAC. He currently works as a regional manager who oversees operations in 24 states; his main task is to establish a nationwide distribution network for NAVAC products. Andrew recognizes the need for communication between wholesalers/manufacturers and technicians, especially in the areas of education and product demand. To bridge that gap, the sales representatives act as middlemen between manufacturers and consumers. Representatives must know what the consumer demand looks like so that they can effectively sell products that technicians want to buy. Effective representatives must also understand their market and have a grasp on the training necessary to use the products they sell. The ultimate way to connect the manufacturer to the user is through training. Andrew working for NAVAC is a promising move for the industry; he knows how techs use tools in the field and what they need to succeed in their work. When people bring field experience to the manufacturing world, they can meet technicians' on-the-job needs while keeping their businesses afloat. When these businesses stay in the game, they can continue to provide quality tools that truly help technicians. Andrew and Bryan also discuss: Taking a technical background to sales Misunderstandings between wholesalers and technicians Stigmas against sales reps Production of good tools Analyzing the market Combatting the "BS" sales response Commitment and sacrifice in the HVAC industry Viable career paths beyond the field Putting out online training and content to make a name for yourself Check out NAVAC at navacglobal.com. Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In this short podcast episode, Bryan covers the bypass factor in airflow and psychrometrics. He also explains why it matters to techs. The bypass factor is a ratio: you take the difference between the evaporator coil temperature and outlet air temperature as compared to the inlet. In other words, you find the difference between your TD and delta T. When air moves over the coil, only some of it contacts the coil's surface. Therefore, only some molecules will become the same temperature as the coil. Other air molecules will bypass the coil, which typically happens when coils have a lower surface area. Evaporators have fins to increase the coil surface area, which helps those air molecules bump into the coil and transfer their heat. Without those fins, your performance will suffer; the saturated suction temperature will drop, and your temperature split will be lower, indicating a higher bypass factor. We want that air to have MORE contact time with the coil; therefore, we want a LOWER bypass factor. However, when we account for total enthalpy change across the evaporator coil, we also have to look at the latent content; that topic can get complicated and theoretical very quickly, so we avoid that discussion for the sake of simplicity. The bypass factor also accounts for contact time, which is the amount of time needed for the air molecules to transfer their heat to the refrigerant. You can reduce air velocity to increase the contact time, which is the inverse of the bypass factor. Bryan also covers: Coil types and impacts on bypass Impacts of coil size on dehumidification CFM adjustments with varied coil sizes Sensible heat ratios (SHR) and installation considerations Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Colleen Keyworth from Women in HVAC/R comes on the podcast to talk about the importance of getting women excited about our trade. While many women take up administrative roles in HVAC/R companies, very few women work in the field. Schools don't tend to market trade schools to women (or in general), so we can attribute part of the gender gap to how high schools present career options to people. Women in HVAC/R as an organization helps educate young women about career options in the trades. Colleen also has a very positive view of the industry and the values that contractors tend to promote. In general, women just want to be treated the same as men; women who go for HVAC careers want to be part of the rule, not seen as the exception. Colleen believes that female techs don't require any special considerations as long as the company culture is already intact. To get women interested in the field and set them up for success, we just need to be clear about expectations and what the job entails; the heavy lifting is only a small part of the job, and the physical disadvantage sometimes gets overblown. The pillars of Women in HVAC/R are membership, sponsorship, mentorship, ambassador programs, and networking. Memberships are for all people who have a common goal of promoting a greater female presence in the HVAC/R industry, regardless of gender. The ambassador program is what really focuses on reaching out to young women in high schools. Colleen and Bryan also discuss: Women's success in sales How women overcome the physical strength gap Support of men in the HVAC industry Non-inclusive environments in the past Generational differences Learn more about Women in HVAC/R and consider becoming a member at womeninhvacr.org/. Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In this short podcast episode, Bryan explains the ins and outs of vacuum pump maintenance, a critical component of evacuation. The most basic part of vacuum pump maintenance is changing out your vacuum pump oil. This practice should happen very often. At a minimum, you should replace your vacuum pump oil weekly; in very wet or contaminated systems, you may need to replace it multiple times during the same job! When moisture gets into the vacuum pump oil, it can wear out your vacuum pump well before its time should be up. So, most of the maintenance practices exist to reduce the risk of moisture damage. Good-quality pumps can last for several years with the proper attention to oil management. If you can cap the outlet of the pump, then that's a good idea to prevent moisture from getting to the oil. You'll also benefit from leaving your gas ballast open until you get down to the 500-micron range. You'll want to keep your vacuum pump in a place where it won't be jostled or thrown around. It's an expensive piece of machinery that shouldn't take too much abuse. Store your pump in an accessible but secure location. When it comes to evacuation, be sure to use dedicated hoses. Dedicated hoses don't hold moisture because they are vinyl; you can make them even safer by keeping your hoses capped off. All pump ports should also be capped when they are not directly in use. Test the pump periodically; it should pull down to under 50 microns. If not, the pump will have a hard time evacuating adequately. If you want to test your micron gauge on the pump, keep in mind that the micron gauge will leak. Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

David Holt from NCI comes on the podcast to talk about airflow testing and its importance as a customer service tool for the HVAC trade. Charging and airflow are closely linked. Even though the charge may be correct, the system can't operate correctly if the airflow is off. For example, we can only get the most latent heat removal in humid climates if we run lower fan speeds. To get the right balance, we need contractors and technicians to be educated on airflow so that they can make the correct adjustments. (Remember your ABCs: Airflow Before Charging.) Testing airflow may require you to make adjustments to the system, such as installing test ports. You need to be able to measure static pressure in your system, and you can tell if previous contractors have done it or not by the presence (or absence) of test ports. On the customer service side, pointing out the lack of test ports or other testing evidence allows the customer to discredit the previous contractor; you don't have to be negative about someone else to get customers to trust your company over the others. Testing also keeps your installers honest; almost everybody will realize that their company has made mistakes after they test the system airflow. One of the best ways to educate customers is to speak in terms they understand. For example, David compares static pressure to blood pressure in our bodies. In that same vein, we'd be committing malpractice if we refused to test airflow or disclose our test results. David and Bryan also discuss: Qualitative vs. quantitative data Low-bid contractors System airflow impacts on combustion How to measure static pressure Pressure drops across coils and filters Variable speed motors Sales vs. technical excellence Premium pricing and earning what you're worth Check out NCI at hvactoday.com. Also, check out the AirMaxx Lite app. Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In this short podcast episode, Bryan covers the basics of sunk costs. He explains what they are and what they mean for you and HVAC businesses. Sunk costs are costs to decisions that have been made in the past. You've "sunken" money, time, or effort into a decision. Let's say you invest in tools; after you make that purchase, the cost of the tools will become a sunk cost. The cost merely occurred in the past. It is a good idea to reflect on these costs as something that is already over; you can reflect on these costs as a lesson for how you invest money in the future. It is not particularly helpful to view sunk costs as a past cost that keeps you down. The same mindset applies to employment. Someone may hire you, and you may realize that the job is exactly what you thought it was; other times, the job may be a poor fit. If you can look back and say, "If I could redo the choice to take this job with what I now know about it, I wouldn't take it," then you may want to consider finding another job. In other words, sunk costs allow you to reflect; they aren't a specific category of costs like overhead. Very few situations require us to take pause and reject attachment to sunk costs. In short, viewing past decisions in terms of sunk costs can help us make logical decisions about buying tools, hiring employees, and accepting employment offers. Sunk costs factor your experiences into decision-making, but we have the choice to cling to those costs or detach ourselves from them. Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Steve Rogers from the Energy Conservatory comes on the podcast to talk about residential air balancing and flow hood accuracy. Residential air balancing is important because it contributes to comfort in the home. To achieve the most comfort possible, we need to know where the air is going inside the home. For example, some rooms may be more conditioned than others, even if they may need less conditioning than the under-conditioned rooms. A flow hood can give us some data about the airflow in the ductwork; there are cases where dampers may be closed, which blocks airflow and contributes to customer discomfort. Load calculations can only help so much. Systems require flexibility because air distribution can vary across seasons or throughout the day. HVAC systems won't always perform under design conditions, so it's a good idea to think about customer comfort above Manual J or Manual D calculations. Flow hoods are some of the best tools for residential air balancing; they can tell you where there is flow and where there is not. However, flow hoods are expensive and may not be completely accurate if they haven't been calibrated correctly. Many manufacturers use a single supply register configuration or wind tunnel for calibration. Many flow hoods use a pitot array, which is a grid that attaches to a manometer. Others use the RPM of an impeller to measure the flow; they also compensate for resistance. Some hoods also use vane anemometer technology. You can typically determine the insertion losses by looking at the hole size. Steve and Bryan also discuss: Pressure vs. velocity Air handler location Load calculation (Manual J) Balancing dampers Anemometers vs. flow hoods Insertion loss Flow conditioning Building envelope construction TrueFlow Grid Accuracy questions about flow hoods Check out THIS webinar with Steve and Bill Spohn. Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In this short podcast episode, Bryan covers the unique practices of brazing steel. He also explains how it differs from brazing copper. Brazing steel appears to be a rather uncommon practice in the HVAC industry. However, we actually do braze steel when we braze in compressors. Many compressors have copper-plated steel stubs; only the outer coating is copper, and if you burn through it, you'll reach the steel. However, steel requires a different fluxing agent than copper-to-copper or copper-to-brass brazing; you can't use a 15% silver-phosphorus rod because phosphorus doesn't react well with steel. Instead, you will need a high-silver rod WITHOUT phosphorus when brazing steel to steel, copper, or brass. We recommend using a separate fluxing agent or flux-coated rods. However, high-silver rods are expensive and REQUIRE flux. When working with a compressor with copper-plated steel stubs, try to get all the solder off with heat. When working with steel, you must keep in mind that it has a higher melting temperature and lower thermal conductivity. In other words, you can apply more heat to steel without it melting, but the heat doesn't transfer to steel as easily as it does to copper. You'll want to move your torch around more and pay more attention to the tip you use. Even though the thermal properties differ from copper, you're still aiming to get the steel to a dark cherry red color, about 1200 degrees Fahrenheit. Remember, you also want to protect any other components that will come into contact with the heat. You can use a wet rag or Refrigeration Technologies WetRag, which works great as a heat-blocking putty. Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

John Pastorello from Refrigeration Technologies is back on the podcast to talk about leak detection procedures from start to finish. Big Blu was what started the Refrigeration Technologies empire. John developed Big Blu to create a bubble leak detector with a higher sensitivity to leaks than any other bubble test solution on the market. Big Blu differs from other leak detection solutions because it detects gas leakage down to 0.65 ounces per year, putting it on the same level as some of the best electronic leak detectors. One of the most common misconceptions in our industry is that systems don't leak at all. That is simply not true; all systems leak to some extent. When we check for leaks, we want to check for unacceptable leak rates; detectors will normally reveal when a leak occurs at an unacceptable rate. Most of the leaks we check for are standing leaks, which we pinpoint when the system is off. We also have pressure-dependent leaks, temperature-dependent leaks, and vibration-dependent leaks. Those leaks vary with system operation, and you may even hear the leaks when the system is under a certain set of conditions. Overall, you want to use your senses to look for oil spots, listen for hisses, and feel for oil residue before using an electronic leak detector. If you get a hit, pull out the Big Blu. When using soap bubbles, also be sure to use a mirror and light source to look all the way around a joint. John and Bryan also discuss: Pressure distribution in the compressor Leak rate and molecule size Leaky valves and mechanical issues Cumulative micro-leaks Losing refrigerant from hooking up gauges repeatedly Leak detector sensitivity and calibration Efficiency during leak detection Oil spotting Evolution of leak detectors Checking for leaks on furnaces Testing leak detectors Learn more about Refrigeration Technologies HERE. You can also find their FREE Leak Detection Manual HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE

In this short podcast, Bryan dives into enthalpy. He explains what it is and how we see it at work in the HVAC/R systems we service daily. Enthalpy is a fancy word for the total heat energy within a substance. Don't confuse it with entropy, which is the disorganization of energy in a system. We measure enthalpy in energy per mass unit, such as BTUs per pound. Enthalpy combines both the sensible and latent heat capacity; for example, it may represent the energy that it takes to evaporate the water contained in the air. (Water vapor is always present in the air, not just at boiling. Evaporation also occurs at many temperatures below the boiling point.) So, the more water vapor in the air, the more enthalpy there is. Believe it or not, water vapor is less dense than dry air. So, we can't equate thermal mass to density. Air with a heavy concentration of water vapor has lots of latent heat trapped inside the water vapor. However, we won't recognize that heat until that water vapor condenses to a liquid at the dew point, such as on a cold evaporator coil. Relative humidity measures the moisture in the air as a ratio. An RH value of 100% indicates that the air is at saturation. That is also the point when the dry-bulb and wet-bulb temperatures will be the same. Overall, we don't care very much about enthalpy values on their own; in HVAC work, we want to calculate changes in enthalpy across parts of the system. We care about changes over the coil, such as drops over the cooling coil. Psychrometers come in handy when you are trying to look for trends in the enthalpy content of the system. Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE

Jim Devlin from Weil-McLain joins us to talk about high-efficiency and cast-iron boilers. He also explains how to use them together in a "hybrid" configuration to serve your customers. Cast-iron boilers are standard-efficiency boilers. These boilers are "standard-efficiency" because they have higher return water temperatures; you typically measure about 330 degrees in the flue. Conversely, high-efficiency boilers have much lower return water temperatures, only around 180-190 degrees in the flue. The goal of a high-efficiency boiler is to get more BTUs out of the fuel, so your flue gases will be cooler. However, the standard boiler can be better for thermal transfer and gives us more leeway for our flue temperatures. Hybrid boiler plants aim to eliminate inefficiencies by using cast-iron and high-efficiency boilers together. These hybrid configurations usually exist in older constructions, but you also see them in new constructions with dual-fuel burner systems or where high-efficiency boilers won't have a good value on their own. You will often see a greater ROI on systems that use cast-iron and high-efficiency boilers together than on systems with multiple high-efficiency boilers. Hybrid configurations usually set up dissimilar boilers in series with a primary-secondary loop. The controls usually use sensors and 1-10v DC output signals, so these controls can modulate the burners. Many people make mistakes when piping these boilers; they don't understand the parallel positioning of the tees. When installers make these mistakes, the boilers lose efficiency. Jim recommends drawing out the piping to avoid making those errors. Jim and Bryan also discuss: Sulfuric acid and condensate Boiler metals Dual-fuel burner systems Boiler controls Hybrid vs. Combi-boilers Comparing utility reports and checking ROI Energy savings on cast-iron boilers Heat exchangers Future geothermal and solar hybrid systems Visit weil-mclain.com to learn more. Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Do you need different gauges for each refrigerant? In today's short podcast, we discuss the answer to this common HVAC question. When we first started using R-410A, many people warned us that we'd have to use a separate set of gauges when working on R-410A systems. That's because R-410A systems use POE oils, not mineral oil, and they are not compatible. While it is true that R-22 and R-410A systems use different oils, there is no need to worry about using separate gauges for each type of system. Actually, some manufacturers recommend using a little bit of POE oil in mineral oil systems. What you cannot do, however, is mix the refrigerants themselves. Many of the gauge hoses have quick disconnects, which cause some confusion regarding the de minimis rule. (The de minimis rule permits tiny refrigerant losses from regular servicing, and de minimis DOES protect us.) However, we aim to keep our hoses clear anyway. We do that by bleeding liquid refrigerant back into the suction line after servicing. So, the real concern doesn't lie in which refrigerant we use with our gauges. The real issue is about taking steps to avoid contamination of the entire system and stay in compliance with EPA standards. Mixing POE and mineral oil does not negatively affect a refrigeration system; however, moisture does pose a threat to POE oil. Again, the core issue deals with best practices: flushing and purging hoses, minimizing the risk of hydrostatic pressure, avoiding venting, and avoiding mixing refrigerants. Of course, you don't have to worry about any of these problems and practices if you check the charge without gauges. Using probes is an easy way to get good measurements without worrying about contamination Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In this two-part interview, Moe Hirsch goes deep and wide on buffer tanks and strategies for "parking" BTUs in hydronic systems. Systems with a high domestic hot water load can also benefit from a buffer tank. You can pipe the domestic hot water tank as its own zone and step down the rest of the structure. However, there will be some standby losses for a tradeoff greater capacity. You also cannot use the buffer tank as an air eliminator or separator; they work only for BTU parking. Contrary to popular belief, buffer tanks do NOT prevent flue gas condensation. If the buffer tank reaches 120-130 degrees, then it may prevent flue gas condensation via the flywheel effect. Flue gas condensation on boiler systems has to do with excess air, combustion, and run cycle length. Moe and Bryan also discuss: Water storage temperature Using a biomass boiler as a backup Stratification: tall tanks vs. wide tanks Cycle times and mathematical formulas Outdoor reset targets Boiler startup conditions Manual reset high limit

In this two-part interview, Moe Hirsch goes deep and wide on buffer tanks and strategies for "parking" BTUs in hydronic systems. When we use boilers, we want to use a heat sink to "park" BTUs in a buffer tank so that we can temporarily store extra heat and avoid short cycling through load matching. However, few boilers have an actual buffer tank; many systems have a means of creating a buffer, though. Buffer tanks are good for parking BTUs in systems with zones and microzones that require varied heating needs. The amount of BTUs you store depends on the temperature difference between the beginning and end of the tank and the water quantity. Moe and Bryan also discuss: Pressure tanks Variable frequency drives Getting extra BTUs Snowmelt systems and Combi-boilers Two-pipe and four-pipe configurations Creating and positioning buffer tanks Hydraulic and air separation Reverse indirect water heaters Parking BTUs in concrete Dirt and magnetic separation

In today's short podcast episode, Bryan covers the basics of refrigerant oil in HVAC/R systems. He also discusses what technicians can do to maintain oil systems. Oil lubricates the moving parts of the compressor. So, oil moves with the refrigerant and lubricates the parts as the refrigerant moves through the compressor. Unfortunately, oil can migrate to other parts of the circuit when it's not supposed to. Flooding occurs when liquid refrigerant enters the compressor crankcase, and slugging occurs when liquid gets into the compressor head. When either of those happens, they can eject oil from the system. When a system has insufficient oil, the compressor's moving parts can heat up and wear out quickly. We can use an array of preventative strategies to keep oil in the system and reduce the risk of compressor damage. We want to keep our discharge lines below 225 degrees to prevent oil (or lubricant) breakdown. To prevent the compressor from overheating, we want to look at mass flow rates and compression ratios. We should also make cleanliness a priority, as dirty components can increase the compression ratio. Oil has evolved with refrigerants. We largely used mineral oil with HCFCs like R-22, but we have begun using POE oil with HFC refrigerants like R-410a. Newer HFCs are generally NOT miscible with mineral oil, but we must be careful with POE and PVE refrigerants because they are hygroscopic. These oils break down via hydrolysis when they react with moisture, and they become acidic. So, we need to keep POE and PVE systems dry to prevent damage. Bryan also covers: Hard shut off TXVs Pump down cycles Oil return Viscosity Oil velocity and pipe design Miscibility AB oil Check out our oil article HERE. Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In today's podcast, Kevan Mayer from NAVAC comes talks about recovery and ways to make it work better and more safely for you. Recovering refrigerant is better for the environment and safer for us. When designing recovery equipment, NAVAC's goal is to limit the gases we put into the atmosphere and leave the planet in better shape than we gound it. Recovery also ensures that refrigerants for phased-out refrigerants remain available. Tanks require vacuums of at least 1000 microns, if not deeper. We also need to remember what the previous tank contents were to make sure that we only fill the tank with those refrigerants and oils. You absolutely DO NOT want to mix refrigerants. Tanks should always be up-to-date and must be certified every 5 years. When recovering refrigerant, one of the best practices is to use a filter-drier to filter out moisture and contaminants. Reducing moisture and contamination will increase the life of your recovery machine. However, a filter-drier will not restore refrigerant back to the highest purity standards. The speed of your recovery will depend on your vacuum, recovery machine, hose sizing, and core removal. You can also raise pressure by turning the fan on. The goal to produce speedy recoveries is to reduce tank pressure and increase system pressure. When it comes to filling the tanks, we must pay attention to the tare weight and water capacity. However, we must understand that the water capacity is NOT the same as refrigerant capacity. We need to do a little bit of math to fill our tanks safely. Kevan and Bryan also discuss: Evacuation vs. recovery Reclaim company tank-handling protocols Refrigerant mixing costs/consequences Using recovered refrigerant legally Compression ratio Hose sizing and manifolds Push-pull method The 80% rule NRDD recovery machine Learn more about NAVAC tools at navacglobal.com. Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In this short podcast episode, Bryan covers the difference between volt-amps (VA) and watts when we take electrical measurements. We usually use VA to rate transformers, but we use watts for other electrical ratings. Even though you can multiply volts by amps to get wattage, the difference between VA and watts has to do with the power factor. Power factor is the ratio of apparent to active power. VA is the apparent power, and watts is active power. The difference between volt-amps and watts is called KVAR (kilovolt-amps reactive). The reactive volt-amps are not effective; you can compare them to the foam on a beer (if the entire beer is the VA, the watts are the actual beer). When we look at motors, we want to know how much actual work that motor is doing. That's why motor ratings are in watts or horsepower; the utility company is also probably going to charge you in watts. However, we want to measure transformers in VA because we are more concerned about the exchange of current, not necessarily the work to be performed. (Smaller transformers use VA ratings, while larger transformers have KVA ratings.) Our goal is to have a power factor of 1, as that indicates a minimal amount of ineffective reactive power. In those cases, our motors and other electrical components will be working efficiently. There is also less unnecessary heat when our systems have a power factor of 1. When our systems get out of whack, we may have to do power factor correction. Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In this episode, I talk with tech, contractor, and consultant Genry Garcia. He tells us about his experiences with independent consulting and helping other contractors in South Florida. A chunk of Genry's work deals with independent consulting, which primarily focuses on helping other HVAC businesses and contractors instead of customers. South Florida has unique climate considerations, and Genry focuses on improving workmanship in a way that works well with the climate. Diagnosis remains important in Genry's work, as he needs to find and solve issues with HVAC companies in his work. Genry and Bryan both believe that the future of the industry lies in a non-judgmental approach towards technicians and customers; Genry's consulting approach aligns with that vision for a better HVAC industry. In South Florida, oversizing equipment is a severe issue. The hot and humid climate of South Florida leads to technicians oversizing the equipment to deal with the heat, but the runtime is too short to help with latent heat removal. So, Genry tries to get the full picture of an install by contacting everyone associated with the installation to gather information. He also focuses his education and training on correct equipment sizing and air balancing to help technicians in his climate zone. Equipment sizing has to do with heat load and air balance. So, some of Genry's work also involves measuring pressures and balancing the supply and return air to maximize comfort. We also have to be aware of balancing heat and moisture when we adjust the structure or system. Genry and Bryan also discuss: Tech support "Competing" for customers Repetitive HVAC training and education Data logging Building occupancy and its effect on load Helping consumers understand sizing issues Load matching Zonal pressure matching Check out Genry's website HERE or contact him via his email address: [email protected] Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In this short podcast episode, we talk about condensate drains. We get into the basics of cleaning, pitch, drain pans, and more. Cleaning drains sounds like an easy task, but it can be a bit time-consuming and difficult to get right. Instead of just "blowing out the drain," you must check the entire drain and be aware of buildup in traps and other hard deposits that form inside the piping. Sometimes, you may need to use cleaners to dissolve the sludge and grime. Cleaning is about understanding the drain anatomy and checking it thoroughly to identify and attack the source of the buildup. You also need to clean the drain pan. Drain pitch is also important for proper drain operation. The horizontal runouts need a slight downward pitch to move the pipe contents. We recommend using 1/4" per foot of fall on horizontal runouts. Insulation is also important on horizontal runouts in areas like attics and other unconditioned spaces. Secondary drain pans should have about 3 inches of overlap in all directions, especially over the supply. Improper drain pan setup can cause messes later, and we don't want condensate dripping all over the place. Make sure you install your units in the proper configuration. Be willing to tweak the design to make sure the drain pan is sturdy and collects condensate well. As you would ensure that your unit is level, you need to make sure the secondary drain pan is level and supported properly. You also need to think about float switches. If you have multiple float switches, you need to wire these in series. These components also require thorough testing; each one should be able to break the circuit. We also discuss: Strapping the drains Venting Double-trapping Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Bert and Bryan discuss the commonly repeated phrase, "refer to manufacturer's specs," in HVAC work. They discuss when referring to the manufacturer's specs works and when it feels like a crutch. Sometimes, you need to read the manufacturer's specs so that you can use the correct kits and components if specific parts or tools are necessary. Without knowing the specific product numbers given in the specs, you wouldn't be able to do the job properly. The manufacturer's literature can also explain equipment performance under certain conditions. In very specific applications, including VRF/VRV systems, you will want to be aware of specific procedures. Manufacturer specs also provide vital information for installations; while manufacturer literature can help with troubleshooting, the manual isn't always always as trustworthy for servicing equipment. However, manufacturer specifications can also be outdated or incorrect. For example, many manufacturers refer to outdated evacuation methods in their literature; they use information based on poor vacuum pumps. Many manufacturers also recommend doing triple evacuation, but a deep evacuation can usually suffice without needing to do a triple evacuation. Manufacturers also aren't aware of products like Nylog that don't contaminate the system, so manufacturers advise NEVER to use thread sealants. Overall, you must understand your equipment and use the manufacturer's specs to help you understand the equipment. If you use them as a step-by-step guide for servicing, then you may be using those manuals as a crutch. Some techs also use the specs to justify certain charges and services, which Bryan finds quite annoying. Bert and Bryan also discuss: Technician profitability Advanced functions in the Ecobee thermostat manual Flare leaks Nitrogen usage Understanding applications and misapplications Customers, equipment failures, and spending money Charging the customer "according to manufacturer specifications" Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

By viewer request, Bryan talks about some solar system basics in this short podcast episode. Solar energy is an up-and-coming power source that will continue to emerge. However, oil is still very inexpensive, so the USA still depends on it quite cheaply. Many consumers also don't like the high up-front costs associated with solar energy. Photovoltaic energy creates a differential that moves electrons. Many customers also object to the bulkiness and lack of aesthetic appeal of solar panels. However, in places with unstable electrical grids like Haiti, using the sun as an energy source makes a lot of sense. American homes with panels can backfeed the grid, which makes the electrical company owe you credit for sending their energy back. The panels also store energy into batteries in areas with a weak electrical grid. However, these batteries can potentially be dangerous and expensive. Lead-acid batteries are commonplace in third-world countries. People use that stored energy at night when the sun can no longer power the panels. You need to calculate panel space, battery size, and peak solar times to create the most efficient system possible. Automatic shifting inverters can kick in and act as reverse charge controls that charge the batteries in both directions. If you were to build an off-grid system, you can set up battery banks, use a charge controller, and connect the system to an inverter or even a generator to provide additional power; your goal is to look for energy gains. Some batteries are rated in amp-hours, so you need to know what that terminology is and how it affects voltage. Panels are often rated in wattage. Be careful about bucking phases; you do NOT want to do that because it is unsafe. You also don't want to use solar on refrigerators or freezers for hot pull down. Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Bryan and Bert talk through a real-life issue we all face as techs: work-life balance. Bert's recent video "triggered" Bryan a bit, so they talk through it. Bryan believes that the work-life balance doesn't necessarily exist; instead of creating balance, he believes in a focus on discipline in work and home life as you're present to each of them. Instead of setting rules for dedicating his time, Bryan focuses on setting goals that can improve multiple parts of his life. That is how he is able to work at a high level in his company, make videos and podcasts, write articles, and raise a large family. The main issue that Bryan has with "work-life balance" is that the term focuses on value rather than focus. The term also implies that there has to be a 50/50 ratio of importance. He believed that Bert's video gave people license to give in to distractions at work. Bert is more inclined to pick up his personal phone at work if his wife is calling. He knows how to make time for his family because he knows how much his family values quality time. However, he understands that creating expectations is not the way to promote focus and balance in life. He knows that it's easy to create an issue when people feel unloved if their significant other doesn't pick up the phone at work, so he and Bryan discuss what love, prioritization, and open communication really look like. Bryan and Bert also discuss: Expectations and disappointment Balance and focus When people change in relationships How a spouse can promote focus in your work and home life Boundaries Enabling others Managing distractions at work Moving forward When are you working too much? Discussing goals and making hard decisions Setting priorities Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Today's short podcast episode is all about surge protection on HVAC/R equipment. Lightning poses a severe threat to equipment, and surge suppression may or may not help. Unfortunately, surge protection cannot protect HVAC equipment from direct lightning strikes. Surge suppression strategies connect to the high-voltage line and will protect your equipment from surges from the utility. Large, instantaneous spikes in voltage can mess up your equipment quite severely. In general, we install MOVs (metal oxide varistors) as surge protectors in residential and light commercial equipment. Series mode (SM) acts as a low-pass filter that blocks higher frequencies, but MOVs are our main go-to for surge protection. When the voltage is within the clamping voltage, the metal oxide varistor shunts or redirects current to ground instead of the device; these devices have very high resistance, and they can fail when they get too hot. In thermal runaway, the MOV is very hot but continues shunting the current; as a result, the MOV is at risk of catching on fire. Thermal protection can exist for MOVs. MOVs also need a strong, secure ground connection to operate correctly. Make sure the MOV is connected, and a good way to do that is to test from leg to ground. MOVs also require careful consideration during installation. These surge protectors can fit inside an ICM493 box that prevents catastrophic fire in the case of thermal runaway. Overvoltages below the clamping voltage can occur on MOVs, especially on inverter-driven compressors. ICM493s can also control overvoltages because they have voltage-monitoring capabilities (however, there is no published Joule rating). Both the LBK10 and ICM493 can shut off the equipment in the case of MOV failure. Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In this episode, we talk with Moe about the world of hydronics. We discuss some fundamentals and talk about various boiler and radiator types. Hydronic systems use water flow to move heat. We can compare these systems to railroads; the water is like a train carrying BTUs, and the BTUs get off the "train" at radiators. The pump moves water in a circle, though it moves that water pretty far. Boilers generally require a certain flow, and if a single circulator pump can't achieve that flow, we sometimes need to bring on a secondary circulator. Radiators can either be radiant or convective. Baseboards are a major part of conventional convective hydronic designs. Fin-tube baseboards are made of copper piping with aluminum fins on them. Cast-iron baseboards also exist and are commonplace in older homes, but Moe avoids installing them on newer homes. When designing systems, you don't want radiators holding on to heat for a long time. Recessed radiators go into the wall and are typically cast-iron; exterior walls require insulation. Freestanding radiators are typical of old designs but are making a comeback. Kickspace heaters go under cabinets and are fan-forced systems. Old boilers are generally cast-iron sectional boilers, and some are steel. Cast-iron boilers tend to be either dry-base (fire on the bottom) or wet-base boilers (power burner/gas-gun type). These old boilers also usually have tube bundles, especially wet-base boilers. Modern high-efficiency boilers are common nowadays. Combi boilers (combination boilers) also fall into the modern boiler category. Combi boilers act as on-demand water heaters. Moe and Bryan also discuss: Relief valves and pressure margins Purging hydronic systems Hydraulic separation Delta T and what it means for hydronics Condensing boiler temperatures Radiant vs. conventional baseboard systems Hydronic towel warmers Humidity and airflow control Boiler runtimes Short cycling and modulation Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In today's short podcast, we answer the following question: Should you ONLY use OEM parts? We also explain why the answer is what it is. It can be tricky to determine the value of OEM parts in general. For example, many OEM capacitors are very prone to failure. Some non-OEM capacitors have much lower failure rates. Operating conditions may also exceed manufacturer specs, so aftermarket components may be better for equipment in extreme conditions. When it comes to OEM parts, try to take those and the manufacturer bulletins at face value. However, you also want to do your own research. What are the OEM parts' fail rates? What are the operating conditions for the equipment? You have to ask yourself if the manufacturer's part is the most efficient and valuable one you can use for a given system. Go the extra mile to help your customers make the best possible decision for their unit based on efficiency, longevity, and price. Some techs avoid using aftermarket parts because of liability issues. For the most part, liability isn't a huge deal except on flammable equipment like furnaces and R-290 systems. However, in many cases, the quality of parts like capacitors and relays may be far greater on aftermarket equipment. Motors can be tricky, especially on blower motors with distinct fan curves from the OEM equipment. No matter what you do, make sure you consult with the customer and explain the benefits and drawbacks of each option so that the customer can make an informed decision. Also, follow your own company's guidelines. Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In this rather unorthodox short podcast episode, Andy gives his timeless soft skills tips. We also tell you a bit more about a special training event in Orlando in just a few weeks. Soft skills and communication are critical parts of the HVAC industry, especially residential HVAC. Customers don't compliment you on your tools; they compliment your service and attitude. We must acknowledge that we are in the people business and just happen to use tools when we work. Andy recommends being on time for every job; if you think you might be late, call the customer to let them know. When you greet customers, make sure you smile and be friendly. Put your listening skills first; during that first conversation with the customer, pay attention to them and make sure you let them talk about all of their concerns. When working with a customer, try to make sure that everything you do comes from a place of gratitude. Set the agenda with the customer and make sure that they understand exactly what the service entails. Show the customer everything you come across and involve them in the inspection and service process. Give the customer permission to follow you around and see what you're doing to build up that trust; the customer will know that you're doing your job and not trying to pull a fast one on them. It also helps if you begin to view the customer as a component of the system so that you can keep their well-being at the top of your mind. We are troubleshooters above all, and we would probably all do a bit better if we saw the customer as another part that needs to be taken care of. Find more at TopRate.com. Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In today's podcast, Bryan covers some of the facts about humidity. He also explains how to keep humidity under control in all climates. Humidity refers to water vapor in the air and is a component of the air. Changes in temperature and pressure affect the density of the air. The air density determines how much moisture air can hold. Relative humidity refers to the ratio of water vapor in the air. An RH value of 100% indicates that the air is saturated with water vapor; it has reached the dew point. At that point, the wet-bulb and dry-bulb temperatures will be the same. We do not want to reach the dew point inside a building. Many people associate high relative humidity with high temperatures, but that association is a misconception. Unless the moisture content is extremely high at high temperatures, the RH will tend to be lower in hotter environments; hotter temperatures can hold more moisture. The moisture content at 90 degrees with 55% RH will be significantly higher than the moisture content at 65 degrees with 55% RH. If the indoor temperature is below the outdoor dew point, we need to make sure we keep outdoor air out. We can do that by using ventilation strategies like bath fans and kitchen exhaust, especially since construction companies have built homes much more tightly over time. However, we want to ensure that we don't draw in low-quality air from the attic. We find that many humidity control strategies overlap with ventilation. Bryan also discusses: Wet-bulb depression Insulating spaces and the effect on humidity Dehumidifiers Attic and crawl space dew points Humidity drivers inside the home Coil temperature, airflow, and dehumidification Off cycle fan delay Sweating and equipment freeze-ups Running continuous fan Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In this short podcast episode, we talk about the myth that time at a job or in the business equals or deserves pay increases. Many people believe that showing up for a long time justifies a raise. They aren't necessarily progressing in their field, but they think they've spent enough time to warrant a raise. A business relationship is an agreement that you will perform specific tasks for a specified rate. If you don't go above and beyond or progress, then there's no reason for that pay rate to change. Soft skills, cleanliness, and overall professionalism are also important to job efficiency and performance. If you don't improve those, then you may not give your employer a reason to believe that they should give you a pay raise. You are not owed more money because you have simply worked at a place for a long time. If you work for a company that focuses on sales, the company has to make a profit for them to pay their employees more money. So, improving your own profitability as a tech will give you a case for deserving a raise. Investing in yourself can translate to success within the business. You will be a good earner only if you can bring quality work and skills to the table. You can also choose to move to a different business or segment of the industry. Ultimately, you have to invest in yourself and make decisions for yourself. Your value does not depend on how much time you spend with a company or in the industry. As a technician, your value depends on the work you put into the industry. Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In today's podcast episode, Mark Roth from Goodway talks about chiller and cooling tower cleaning best practices and techniques. Goodway makes industrial maintenance equipment for the HVAC industry, especially tube-cleaning equipment. A chiller has water running through the tubes, and debris from the cooling tower can build up in the tubes. When scale or debris buildup occurs, heat exchange becomes much less efficient. Water hardness can also interfere with heat transfer; harder water will lead to more mineral deposits. So, tube cleanliness is important, especially in high-traffic areas. In those areas, cleaning should happen at least once or twice per year. To access the tubes, you have to take the heads off the chiller. Cleaning the tubes is usually easier than taking the heads off the chiller. When cleaning the chiller and cooling tower, the water flows onto the floor and to a drain. So, floor cleanliness is important when wrapping up a job. "Chiller bibs" also exist to catch the water and transport it to the drain with less of a mess. Cleaning machines often have foot-pedals, and people commonly put toolboxes or other heavy objects on foot-pedals, which is a bad practice. People also need to tighten the brushes to their cleaning machines with channel locks; when techs don't tighten those brushes properly, the brushes can fall off, which is not good for the chiller. Cooling towers act as filters, so they collect a lot of debris in the basin. Goodway has a vacuum that collects the debris in the basin without having to drain the entire thing. Mark and Bryan also discuss: Basic chiller and cooling tower anatomy Legionella Using machines for cleaning Enhanced tubes Nylon, brass, and stainless steel brushes Makeup water and filtration strategies Cooling tower media Descaling strategies and products pH balance Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In this short podcast episode, we address the myth that IAQ is a joke. We also discuss how to think about IAQ correctly in HVAC work. Indoor air quality is NOT a joke. However, it has a bit of a bad reputation in our field due to the overuse of accessories and bells-and-whistles to solve whole-home air quality issues. (Oxidizers, UV lights, etc. can help IAQ issues, but they are not a fix-all.) We don't want completely sterile air, just as we like to have a beneficial microbiome inside our own digestive systems. However, there are also a bunch of things suspended in our air that are really bad for us. Some of those bad things include VOCs, carbon monoxide, and radon. Many of the products we bring into our home, including furniture assembled in underregulated factories overseas, end up off-gassing harmful substances into our air. VOCs have a distinct chemical smell, and proper ventilation helps solve the problem. Media filters are an everyday object that we use to help control IAQ. Using higher-MERV filters help keep the air free of particulates, but you must size them correctly to prevent excessive pressure drop and poor airflow. To control moisture problems, we want to make sure we seal buildings as tightly as possible. We also want to make sure we use designed pathways and effective ventilation strategies. Kitchen and bath exhaust fans should be functional. When we think about bringing in outdoor air, we want that process to be controlled, and we want to make sure we're bringing in high-quality outdoor air. Carbon monoxide and carbon dioxide are both undesirable in terms of IAQ, but carbon monoxide is potentially deadly. We want to make sure we vent those gases, especially CO. Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Chris Stephens from HVACR Videos joins us to talk about his experiences with and perspective on R290 (propane) refrigerant in restaurant refrigeration. Chris sees R290 propane on a daily basis, and his perspective as a tech differs from that of an R290 equipment manufacturer. While the temperature sensitivity contributes to flammability, R290 is also under pressure in a system. Therefore, propane refrigerant systems require a lot of caution. R290 equipment must undergo thorough redesigning to be entirely spark-proof. Hydrocarbon refrigerants also require OEM components; aftermarket components change the design and can cause problems down the line, and technicians WILL be liable for any damages related to aftermarket components. When techs evacuate/recover R290, all evacuation and recovery tools must also be spark-proof; you also need to check to make sure that those tools are certified to work with propane refrigerant, even digital gauges. When using approved service gauges, also be sure to use short hoses. More so than ever, following the manufacturer's guidelines is an invaluable practice. Unlike R-22 and R-410A, you CAN vent R290. However, the location should be well-ventilated. Chris recommends that you take extreme caution when venting refrigerant, such as by using a leak detector to let you know when to stop. Most of all, we need to be aware of our surroundings when we work with highly flammable R290. When we use our senses and are aware of our surroundings, the refrigerant becomes much more predictable. Chris and Bryan also discuss: Buying and sourcing R290 Recommended R290 training resources Piercing valves Basic R290 behavior Flowing nitrogen Evaluating hydrocarbon systems and using a "common-sense" approach Leak detectors to avoid using for R290 systems Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In this short podcast episode, we discuss the common myth about cleaning flame rods/sensors/rectification devices. Flame sensors or rectification rods are NOT the same as thermocouples or thermopiles. Thermocouples and thermopiles use two dissimilar metals to create a temperature differential. So, we do not clean thermocouples and thermopiles because the heavy abrasives in cleaners can damage and reduce the effectiveness of those devices. However, you don't have to worry about that sort of damage on a flame sensing rod; we can indeed clean those. The flame rod sits in the flame (regardless of ignition type) and allows for a DC current to travel through the ions in the flame to ground. The flame creates a path for that current, which makes a closed circuit. Flame sensing rods are merely pieces of metal that allow current to flow when there is an active flame on a furnace. So, you want to keep your flame rods clean to allow for conduction. You may want to avoid using sandpaper or Emory-type materials to clean the rods because sediment can build up on the flame rod. When the flame ignites, the sandy substance on the rod can turn glassy and impede conduction. However, you can use an appropriate cleaner without damaging the rod. You can also replace the rod if you happen to have one on your truck, but you don't have to replace all dirty rods. Pool heater flame sensors can get exceptionally nasty due to the chemicals they encounter. If a piece of equipment has a flame rod that gets dirty a little too quickly, try to find the cause of the excess grime and take care of it. Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In this podcast episode, Eric and I discuss his new home and his plans for installing central air the Eric-Mele way. Eric's home doesn't have an attic, crawlspace, or basement. So, designing and installing central A/C will be a challenge, especially since Eric doesn't like high-wall ductless systems. Eric considered using an air handler with exposed ductwork, but he doesn't want the noise issues associated with that design. He also considered using a package system, but it has the same noise concerns as the previous option. In the end, he decided to go with ceiling cassettes. Cassettes have a condensate pump, differentiating them from high-wall ductless systems and making them a bit more expensive. Eric has also collected his latent-sensible capacity data. Moisture removal is critical in his South Florida home, and equipment sizing is an important factor when installing central air. Sizing contributes to dehumidification because of its effect on runtime. However, smaller ductless/VRF units may not have sufficient heat even when they're properly sized. In the future, we expect companies to utilize heat sensors to improve the sensible heat ratio when moisture removal is needed. For filtration, Eric plans on seeing how the fan motors react to pleated filters. Upgrading the filters could help control sensible heat ratio and VOC contamination, but static pressure remains a concern. We also discuss: Ductless unit cleaning Filtration for air handlers with exposed ductwork Lagging vs. drilling Ceiling cassettes and condensate pumps Flex vs. duct board vs. metal ducts Oversizing VRF Two-pipe systems Activated carbon filtration Making flare fittings vs. brazing in factory-made flares Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In today's short live podcast, Bryan discusses the importance of context in education and the challenge presented by information. When we learn, we do ourselves a disservice by searching for information alone. Just-in-time education allows us to "search instead of research," and it works in a limited and inefficient way. Instead, we'd be much more effective if we knew how to learn efficiently. To learn efficiently, we need to bring context to the learning process. Instead of focusing on raw facts or abstract information, we need to know about the surrounding information. It's also beneficial to use similes and metaphors to grasp how something works. In other words, we need to connect new information to past experiences. Therefore, the learning process that most of us accept seems rather backward. Instead of feeding people answers immediately, we can supply them with experiences that can help them draw similarities between those experiences and demonstrations and the theoretical elements. The goal of context in education is to equip us to understand situations and solve problems repeatedly. As humans, we are likely to forget information that is fed to us directly and not connected to our experiences. Ideally, a learning process would begin with observation. We would show students how to do something or how something works. Then, we explain the theory behind why that thing works. Finally, the student or apprentice would be given the space to apply the principles themselves and work with their own hands. We also answer questions and respond to comments about: The value of schooling MeasureQuick compatibility Self-driven curiosity Companies working with educators Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In this episode, Jordan Cummings comes on the podcast to review application-based system selection considerations for VRF/VRV systems. A VRF/VRV system works a bit like a hydronics system, but it provides hot or cold air to various zones in a space, not water. The key to having a reliable and long-lasting VRF system is a good installation. Proper maintenance practices, including pulling deep vacuums for dehydration, will also improve the performance and life of a VRF system. When you choose a system to install, you have to determine if you want a heat pump or heat recovery system. Occupant type will play a major role in that equipment selection. Budget is also a variable, but it is typically less of a concern than occupant type and building purpose. Some VRF/VRV systems that have been primarily designed for cooling may need to provide heating in low-ambient conditions. In many cases, these will close fresh-air dampers and recirculate discharge gas. Some units may even have auxiliary heat or be backed up by other heating equipment. Defrost is also something you'll need to consider in low-ambient applications. Sizing is another important part of VRF/VRV selection and design. Consider nominal capacity but don't accept it as a hard and fast value. Keep your design conditions in mind; which temperatures and humidity percentages are you trying to maintain? What is the outdoor air temperature? Also, think about the piping total equivalent length and the estimated total distance between the outdoor unit and the farthest indoor unit. Jordan and Bryan also discuss: Buildings with cooling towers and boilers SEER vs. IER Aurora VRV equipment and technology Connection ratio Air handler unit and branch box selection Control boxes and accessory selection Discharge air control Condensate control Maintenance concerns for VRF/VRV systems Indoor unit turn-down Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In today's short podcast episode, we talk about specific gravity, also known as relative density. We explain why it matters to technicians. When we talk about specific gravity, we're actually talking about density. We're actually using that value to assess how a vapor or liquid's density compares to air or water, respectively. Regardless, we are working with the pressure conditions of 14.7 PSIA, or atmospheric pressure. In the case of liquids, we're relating them to water is at its densest, which is 39.2 degrees Fahrenheit. You may have noticed that ice cubes float in water. That's because water becomes less dense as it gets colder than 39.2 degrees and when it freezes. Ice is less dense and more buoyant than water. So, specific gravity requires a reference. Because it requires a reference, it is also a relative measurement, so "relative density" is another appropriate term for specific gravity. Regardless of units, we are still comparing one thing to a constant in the form of a ratio. (For example, a liquid with a specific gravity of 0.85 is equal to 85% of the density of water at 39.2 degrees Fahrenheit.) The relative density also explains why some liquids sink and others float when mixed together. Gases can also rise or sink based on how much lighter or heavier that gas is when compared to air. If the specific gravity of a vapor is less than one, it will rise to the ceiling. Natural gas is an example of that. If the specific gravity of a gas is greater than one, it will sink. LP is heavier than air and will sink. Therefore, LP is a bit more dangerous than natural gas because of how it takes up space due to its interaction with the air. Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In this episode, we speak with Embraco about R290 (Propane) refrigerant, hydrocarbons, and what you need to know about them. Embraco is primarily focused on compressors and is involved in the residential and light commercial market. The greater demand for natural refrigerants or hydrocarbons has made R290 popular. Hydrocarbons have hydrogen and carbon chains; although these refrigerants are very similar to grill propane, they are much drier and purer. R170 is another hydrocarbon for very low-temperature refrigeration. In some European countries, R290 and CO2 are becoming much more prevalent than synthetic solutions. China has invested a lot in hydrocarbon technology, and the United States has shown interest in using hydrocarbons for auto coolers and natural refrigerants for grocery refrigeration. R290 is flammable, but most techs' aversion to working on those systems likely stems from a fear of the unknown. These systems have several safety controls that prevent gas leakage from getting in contact with sparks. So, these systems rarely ever catch fire. Embraco also has a commitment to putting safety first when they design compressors. You can also vent R290 to the environment, which you can't do with many other refrigerants. Unlike other refrigerants, R290 has a very low global warming potential. R290 and CO2 are not perfect, but they will be the future as we move away from ozone-depleting substances and greenhouse gases. R290 is also making its way into the residential sector. You can find it in smaller applications, such as mini-fridges and even some other domestic refrigerators. We also discuss: Overloads and why systems aren't as flammable as they seem Terminal venting Embraco's design goals and philosophy Contamination and evacuation Links: http://refrigerationclub.com/ http://naturalrefrigerants.info/ http://embraco.com/Default.aspx?tabid=40 Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

We talk about measuring tricky amperage on a blower and condensing fan motor. We also cover why you may be measuring inaccurately, resulting in a misdiagnosis. When measuring amperage on a PSC blower motor, you may have noticed that amperage on the common is higher when the panel is off. Conversely, on ECM or X13 motors, the amperage is generally lower with the panel off. When measuring amperage, we recommend using a Bluetooth ammeter to take readings without letting the panels interfere with your measurements. Anytime the amperage is low, the more difficulty the ammeter will have in measuring an accurate value. In cases where you're dealing with a very low amperage, you will need a higher-resolution ammeter for accurate measurements. One old-school way that you can increase your resolution is by using the 10-wrap method and putting that in series. Then, you take the amperage measurement and divide it by 10. We don't recommend doing the under-load test on a blower; a bench test is much safer. However, the compressor and condenser fan motor capacitance can be measured under load. Outdoor tests can be a bit challenging because there is a greater possibility for interference. Current drawn outside of the clamps can indeed affect the reading, and several other nearby conductors draw current inside condensing units. Sometimes, technicians replace perfectly fine run capacitors because the amperage seemed too high on an under-load test. To avoid interference, perform a bench test and check the actual microfarads. Tricky amperage interference also leads techs to condemn condenser fan motors when they really just picked up amperage outside the clamp. So, keep in mind that your meter could be running high or picking up interference. Any possible fail parts should undergo further testing to confirm that there's something wrong. Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In this service manual talk-through episode, Eric Mele helps us discuss the Heatcraft Beacon 2 refrigeration system. We talk about what it can do and what it entails. The Heatcraft Beacon 2 is a refrigeration system with more electronic controls than electromechanical. However, it is quite user-friendly, and it allows you to see what the system is doing at almost all times. The monitor doesn't allow you to adjust anything in the system, but it lets you see valve position, superheat, time until defrost, and more as the system is operating. The Beacon 2 has a suction pressure transducer that maintains superheat. You can dial in the superheat on the control, and the system should control it almost exactly as long as all the components are working properly. You can also manipulate the wiring to run multiple evaporators off of one condenser. (There are master and slave evaporators, and you must differentiate them when configuring the controls.) When it comes to parameters, you have to set your defrost type to air or electric. In general, you use electric defrost for freezers. You must also set your refrigerant type accordingly. Then, you set your box temperature. Medium-temperature applications tend to be around 35 degrees, and many low-temperature applications tend to be around -10 degrees. You also have control over defrost settings and temperature units (Fahrenheit or Celsius). You can also find frequent parameters on the evaporator panel for more information. Most errors will be sensor errors. Many sensor issues are easy to test because of the user-friendly monitors. You can compare your reference sensor to the data to check the accuracy of what's being reported to the board. Eric and Bryan also discuss: Forcing pump-down and defrost Schematics and wiring practices/applications Headmaster valves Setting pressure controls Defrost frequency and failsafe Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

This short podcast episode covers the why and the how of low ambient cooling and refrigeration. Low ambient cooling refers to operating A/C equipment during low outdoor ambient conditions. Typically, the cap of operation is around 55 or 60 degrees. However, some commercial facilities need cooling when the outdoor temperature is cold. For example, those facilities may have to cool electronics or large volumes of people. In buildings that don't have economizers, running the A/C in cold ambient conditions may be the only option. The same applies to restaurants, which always need to run freezers and coolers. When the outdoor ambient temperature drops, the condenser rejects more heat to the outdoors. Head pressure drops, and there may be an insufficient pressure drop across the metering device. We also can't run A/C evaporator coils below 32 degrees, as there is no defrost mechanism in straight-cool A/C systems. So, the strategy to get around those issues is to focus on raising the head pressure by modulating the condenser fan motor. A fan cycling control can turn the condenser fan on and off based on pressure. So, we try to maintain a fixed pressure in the condenser by allowing that control to shut off the fan when the pressure drops too much. However, fan cycling can be a bit jarring for the system. Motor master controls help modulate the motor by decreasing voltage to the motor. However, that fluctuating voltage isn't necessarily good for the motor. In those cases, you must have a ball-bearing motor. Unlike the motor master, a refrigeration headmaster is a valve that allows discharge gas to enter the drop leg. Variable frequency drives can work with a three-phase motor to vary the speed of the motor. When the speed can vary easily, you can manipulate the pressure. Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In today's podcast, I talk to John Oaks about his experience as a VRF tech in the field, including branch boxes and two-pipe vs. three-pipe technology. John primarily works on the troubleshooting and service side rather than the installation and programming side of the field. Variable refrigerant flow (VRF) systems, also called VRV systems when manufactured by Daikin, are commercial HVAC systems. VRF systems work best in commercial buildings with some degree of fragmentation, like offices and medical facilities. These systems are similar to multi-zone ductless systems, but they operate on a much larger scale. VRF systems have a branch box, which acts to direct traffic between the various zones of a building and parts of the system; the branch box allows the unit to heat and cool simultaneously. A 24v signal drives most of the controls. These controls are "daisy-chained," as VRF systems are very interconnected, and a defrost signal can have up to about 50 destinations to various components. The entire VRF installation process requires careful attention to detail, not just on the programming side. When it comes to common issues with VRF systems, the refrigerant charge is one of the most critical problem areas. These systems mask issues with the charge, so it is difficult to find out if a system is undercharged or overcharged. In addition, you can't weigh out the charge in the same way that you would in a residential system. John and Bryan also discuss: Metering device placement Industry improvements and upgrades Inverter boards Line set length and charge issues Flares, brazing, and ZoomLock Condensate removal and drainage strategies Diversity of zones and efficiency Two-pipe vs. three-pipe configurations Cooling mode, heating mode, and mixed conditions Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

This is a voice-over audio presentation of the article of the same title on the HVACRschool.com website ("The Trade Skills Gap: A Manifesto). The manifesto discusses the value of technicians and the trades in modern society. It also covers the plague of snobbery that we are all too familiar with in the world. You can read "The Trade Skills Gap: A Manifesto" HERE. Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Jason Obrzut comes on the podcast and talks us through his furnace sequence of operation training: "Take It Slow, It's Gonna Blow!" There are 6 main steps in Jason's furnace sequence of operation training. The phrase, "Take It Slow, It's Gonna Blow!" should help you remember the sequence (Thermostat, Inducer motor, Safety switch, Igniter, Gas valve, Blower motor). The first component in the furnace sequence of operation is the thermostat, which initiates the call for heat. So, the thermostat has to send the signal to the circuit board. After the board receives that signal, it sends 120v out of the board to the inducer motor. Next, the inducer pulls the gas combustion air into the heat exchanger. That air will then be deposited into the exhaust. The inducer is what aids the venting action and is a critical part of a furnace. The safety switch is a general term for a negative pressure switch with a hose connected to the inducer housing or heat exchangers. Negative pressure from the inducer motor will close that switch. When that switch closes, 24v goes back into the board. Then, the board sends a signal to the igniter. Now, you will finally begin to see heat delays. Silicon carbide and silicon nitride are common igniter materials nowadays, but they are fragile. Once the igniter has worked long enough, the gas valve opens. We get 24v from the board to the gas valve, which brings on the gas flow and starts a timer. When the timer expires, the blower motor will come on. This component is the LAST one to come on. Jason and Bryan also discuss: Pressures on the flue Cracked heat exchangers Safeties not closing Hot-surface vs. intermittent-spark vs. direct-spark ignition Flame sensors and proving flame DIP switches Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.