HVAC School - For Techs, By Techs

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