HVAC School - For Techs, By Techs

Eric Mele, Eric Kaiser, and John Oaks come on the podcast to talk about commercial PM best practices and what matters most. Drain cleaning is a critical part of the standard commercial PM. You must assess the drainage situation (pitch, length, location, etc.) to plan your cleaning strategy and arrive at the best result: the entire drain gets cleaned. If you use chemicals, you need to be very careful not to let them back up into other units. Condenser coil cleaning is another important PM procedure in both residential and commercial HVAC. However, you don't always need to clean the condenser coils. When you actually need to clean the coils, some best practices include splitting multi-row coils (on VERY dirty systems) and washing the coil against the airflow (usually from the inside out). Lots of commercial equipment use belts, so HVAC technicians should know how to work on them. Unfortunately, many HVAC technicians aren't great at aligning and tensioning belts. Bryan is of the school of thought that many belts that are adjusted should just be replaced. When working on gas equipment on rooftops, you can perform very accurate combustion analysis because the flue is in an ideal location for testing. Grilles are also very important in commercial HVAC, and the best practice is to check them for restrictions. As always, you cannot underestimate the importance of visual inspection, "do no harm," and making sure the equipment is running when you leave. The Erics, John, and Bryan also discuss: Drain pan cleaning tips Neutralizing algae in drains Clearing drains with nitrogen or shop vacs Transfer pumps Paperwork and documentation Environmental reasons NOT to clean coils needlessly Microchannel coils Quoting specific procedures Belt longevity Browning tools and literature Checking for phase imbalance Benchmarking equipment Maintenance people vs. technicians Communication 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 live podcast from CASTBOX, we discuss the skills gap and how we are going to get more people into and trained in the HVAC/R trade. Instead of gaining skills early in life and then looking for a job, many of us in the HVAC/R trade started our careers and gained skills along the way. The most successful technicians (and Bryan's favorite job candidates) have the "growth" mindset and care about their work, not just connecting a paycheck. Many people have experience working with their hands (or working any job), but they don't go into the HVAC industry with trade experience under their belt. Work ethic and care for one's work are more indicative of success than prior skills. From a contractor standpoint, Bryan thinks that we must teach and force the application of skills. The basics are important, and being a "hands-on learner" is not an excuse for a technician not to learn the basics. Repetition and muscle memory are a major part of learning in our trade; however, they are undervalued in the classroom. It's all about striking a balance. As a society, we don't see as many people involving their family members in the trades. As a result, our trade currently has a hiring and skills gap. It's up to us to get people excited about the trade and help them get involved. We must make it clear that HVAC/R careers ARE good careers where you CAN make a nice living. We also discuss: Hiring out of desperation Self-control and maturity regardless of age Successful techs from other industries and hard times The Diagnosis Game Company culture Successful communication Formal vs. informal performance reviews Interpreting hiring exams, interviews, and phone calls Proficiency timeline and career evolution Learning without an internal training program Competitive starting wages Better high-school programs Socratic method Getting younger people involved in the trades and job-shadowing Being safety-conscious Apprenticeship programs HVAC/R teachers Being intentional about training 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, Nate Adams and Michael Housh give the HVAC 2.0 rebuttal to the idea of standard load calculations. They take a different, possibly more radical approach to proper sizing. Michael and Nate believe in doing real-world load calculations, not just relying on models for load calculations. They are on the side of replacing equipment like-for-like unless the customer will pay for the proper load calculation; customers should have the option to get a free quote for a like-for-like or slightly smaller replacement or a full consultation, but they will often opt to choose the free quote for a similar or slightly smaller unit. The full consultation includes blower door tests and load calculations, which are keys to proper equipment sizing. Even once we do all the typical tests for consultation (blower door, duct leakage, load calculation), there is still some room for ambiguity. The tests are not all-telling, but they exist to help the contractor and homeowner decide what the next step should be. No matter what, there will be some degree of guesswork, but there will be far less guesswork if you perform all the tests and look at utility usage. Some problems can be "HVAC'd away," but excessive leakage may require work on the actual shell of the home to address cracks and infiltration points. To "HVAC problems away," proper equipment sizing will play a major role in promoting comfort. Nate, Michael, and Bryan also discuss: Like-for-like tonnage Building customer relationships through consultation Windows and radiant heat loads Natural pressurization vs. blower door testing Sizing increments and room for error Air changes per hour (ACH) Assessing leakage rates Moisture problems and dehumidification Load calculation theater The consumer-oriented mindset Diagnostic pyramid Natural leakage Communicating testing practices to your sales team Learn more about Nathan's work, go to energysmartohio.com or natethehousewhisperer.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 true story from Bryan's teen years, you learn about the "Freon Sniffer:" what inspired him to become an HVAC/R technician (maybe). When Bryan was working with his uncle at age 14, he was an electrical apprentice who worked in grocery stores. He installed "pink lights," which were lights that hung on aircraft cable over produce displays. (The aircraft cable came from Bryan's grandfather's aircraft junkyard.) The pink lights were difficult to install, and many people were unwilling to do the installation. However, Bryan and his family were willing to install that difficult equipment. Bryan primarily assembled the lights and didn't do any particularly dangerous work. Bryan and his family traveled around the state, staying at hotels and working at grocery stores across the state. In a remote Florida town, Bryan's uncle and a coworker discussed something about checking a "Freon sniffer." They promised to show Bryan what that was. All they said was that "Freon sniffers" just existed to check for refrigerant leaks in the refrigeration piping. What really was it? They tricked Bryan into pressing down the disconnect fitting for the produce sprayer, which sprayed Bryan's face. It was all just an elaborate prank to humiliate him! If nothing else, the situation inspired Bryan to learn more about HVAC/R equipment. Maybe in the future, he wouldn't have the wool pulled over his eyes. 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, Jim explains how to use a combustion analyzer. He also talks through the process of combustion analysis using Accutools BluFlame. The beauty of BluFlame is that it can do CAZ testing, help you set the inches of water column in your furnace, and measure static pressure drop. BluFlame is a tool you can use year-round, not just when you need to measure stack gas. To learn how to use a combustion analyzer on a typical gas furnace, you have to understand why you're doing it. Combustion analysis is necessary to monitor the health of a furnace system; it's like a doctor measuring your blood pressure at each appointment. You must test for carbon monoxide to protect the homeowners from a potentially deadly situation; combustion analysis can save lives. First, we have to test for ambient CO, which can be high in cities with lots of cars and air pollution. Then, we start deploying our tools and set them up to check our pressures. After that, we can start the furnace up to collect our readings all at once, which is easy with MeasureQuick. From there, we can use the readings to help us adjust the input settings. After that, we put our analyzer in the stack about 12-16 inches away from the draft inducer motor. Jim and Bryan also discuss: Jim's involvement in BluFlame Testo probes that do and don't work with BluFlame Clocking the meter and checking input Manometer locations Drilling and sealing holes for testing CO air-free and excess air dilution Overexposing the analyzer to CO Oxygen (O2) content Vacuum in gas furnaces Draft direction Running gas furnaces with other gas appliances (stoves, fireplaces, pool heaters, etc.) Electronic gas leak detectors BluFlame on 80+ vs 90+ furnaces Other gas appliances that require testing 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.

Duct and air handler (unit) sweating is a common issue in humid climates. Bryan talks about what causes it and what to do about it. Many people try to keep their ducts and equipment either very cool or very warm to prevent sweating. Despite the good intentions, neither of those methods is great for sweat prevention. If a ceiling grille is sweating, people try to insulate the top of the boot to stop the sweating. The real reason why the grille continues to sweat is that those sweating areas have hit the dew point. If anything reaches the dew point or lower, you WILL see condensation. Another potential cause is that air with a higher dew point is going into the lower-dew-point space. In the latter case, sealing the ducts and cracks near the boot should help that higher-dew-point air from infiltrating; insulation does very little to address leakage, so air sealing is the real solution. Attics often have air with a higher dew point than the conditioned space. Equipment sizing is also important. Oversized equipment leads to shorter run times, meaning that the evaporator coil can't get cold enough to remove moisture. When you have a low latent capacity, you won't have proper moisture removal in the home. We will almost surely encounter sweating when we have air handlers and ducts in unconditioned spaces. To address duct and unit sweating, some technicians increase the air velocity to prevent ducts from sweating, as the higher temperature should prevent the duct jacket from being below the dew point. However, as with oversized equipment, excessive airflow will negatively impact the latent capacity. So, you will have less moisture removal. The best solution is to decrease the attic dew point or increase duct insulation. Reheat solutions are also worth considering on some 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.

Alex from Wrightsoft is back to discuss duct design. He also explains a common mistake made when designing ducts using a Ductulator. The Ductulator is a common entry point for technicians who get into duct design, so it sticks with technicians despite its flaws. It makes more sense to reverse the process by picking a friction rate and pressure drop as the first step when designing ducts. Figuring out how to overcome restriction is the key to commercial duct design, but it can also work well in residential duct design. However, we can't pull our desired friction rate out of thin air. We have to consider the sources that contribute to the friction rate. We must also consider both velocity pressure (moving forward) and static pressure (pushing against the duct walls). The less restricted the air is, the more energy there will be to go forward; low static generally indicates greater velocity (more airflow). The best designers understand these principles, so many of the best designers come from the HVAC service industry. You can adjust the airflow by balancing duct sizing and restriction, such as from filters. Equipment sizing and Manual S are surely important, but airflow and velocity have a lot more to do with duct design and how fan speed, duct size, restrictions, and air mixing work together to establish comfort. Poor duct design can produce results that resemble those of oversized equipment. Alex and Bryan also discuss: Figuring out desired friction rate and static pressure Changing tonnage and its effects on duct design Load calculations ACCA Manual T Emergency/backup heat Manufacturer coils and pressure drop Rules of thumb Principles at work in HVAC service Use the offer code POD2019 for a great discount on Wrightsoft products at Wrightsoft.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 explains what you need and the things you need to consider if you want to start a business in HVAC/R. When you start a business, you need to have a healthy reserve of money already. Kalos started with $100,000, and that money went towards vans and tools needed for a GC and HVAC business. Even if you start a business with just one person and a truck, it's best to have at least $50,000 available at the start. In the business world, you MUST care about money. Otherwise, you'll go out of business. Profit margin is important, but you must also have a healthy amount of cash readily available at all times. You must have enough cash on hand to weather a storm, and you would be wise to avoid credit card debt at all costs. At the same time, you must separate personal and business funds. You also need to have control of your pricing and know the difference between gross margin and markup. Starting a business is also a commitment that will come with suffering. So, your spouse, kids, and mentors should be willing to help you every step of the way; a support system is extremely important. You may need to pay off the home and car debt, you may work late nights, and you may be frustrated with work at times, so the important people in your life need to be willing to support you. Although hard independent work is necessary for HVAC work, having the right relationships is key. Knowing the right people is better than marketing in your business's early days. Be active in your community and provide excellent, friendly customer service. Discipline, treating people well, hard work, and financial literacy are the keys to starting a business. 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.

Alex Meaney from Wrightsoft joins us to talk about Manual J and S. He also discusses how load calculations and equipment selection apply to real-world situations where contractors are tempted to replace "like-for-like." Load calculations have been a staple of new installations, but they are becoming important in retrofits as well. We consult Manual J when we do load calculations for residential HVAC designs. We determine where the heat loads are coming from to see how equipment can address those heat loads; in heating, we want to replace heat losses. The technicians who do load calculations also tend to get more customers and have better outcomes because they show additional care and can educate customers. We must also be diligent and check our mistakes in calculations AFTER we work on them. In general, most load calculations will NOT determine that upsizing is the right solution. Then, we use our Manual J calculations to use Manual S for equipment selection. When we propose solutions for retrofit installations, we should quote the customer for our recommended solution and like-for-like tonnage. You could also talk with the customers about ways to adjust the heat load; just don't tell them they're wrong, even if they are. It also helps to be straightforward about the health and dehumidification benefits of the best solution versus the like-for-like retrofit option. Alex and Bryan also discuss: When customers are comfortable with oversized systems S.W.A.G. in system design Looking at math AND customer demands Uneducated homeowners and what they do know Don't put thermostats in the hallway Moisture issues, latent capacity, and dehumidification Commissioning "One trip, close" sales Talking to customers about sales and quotes "It's not time wasted; it's time invested" Making time for load calculations and consultation Use the offer code POD2019 for a great discount on Wrightsoft products at Wrightsoft.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 live podcast from the Castbox app, we talk about analog vs. digital, digital vs. probes, and probe vs. non-invasive testing of A/C and refrigeration. We also talk about apps and various Bluetooth tools. Although analog gauges are old, reliable tools, digital gauges tend to be a bit more accurate than analog ones. However, the jury is still out on which one has the durability edge. Digital gauges also have batteries to worry about, whereas analog ones don't. Ultimately, the only reason to use analog gauges over digital ones is a personal preference. Probes work well with hoses, tees, and core depressors. We still use manifolds to this day because they have charging tees and are easy to use, though you can modify probes to make them more user-friendly. Refrigerant can be left over in the hoses, and refrigerant mixing is a possibility. Probes minimize the losses of manifolds. However, non-invasive testing is another manifold-free route. The key to using non-invasive testing effectively is to become a master of the obvious and not to put too much focus on the readings alone. While it is important to know the measurements, it is even more important to use your senses to look for clear problems. When you use tools that connect to electronics via Bluetooth, we recommend using a separate device, not your personal phone. For example, Bryan uses an iPad with a data plan. We also discuss: Five Pillars of HVAC Diagnosis Favorite temperature clamps K-type thermocouples Mandating vs. recommending tools Scales Fieldpiece probes for A/C Sporlan probes for refrigeration Advantages and disadvantages of Testo probes Core depressors Checking light commercial systems with probes Rub-outs When readings are overrated Best practices "Negative" superheat and subcooling 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 talks about ambient CO. He also explains why it matters and what you do to check for it. CO, carbon monoxide, is a colorless, odorless, and toxic gas that can result in death. It should not be confused with CO2, carbon dioxide. Although our bodies inhale oxygen and not carbon dioxide, the latter isn't toxic if it gets into our bloodstream. CO, on the other hand, displaces oxygen, which proves deadly. Carbon monoxide can also build up in your bloodstream over time, so you want to avoid repeated exposure. In some locations, you can expect some degree of ambient CO. For example, lots of car exhaust in busy cities can lead to a low amount of carbon monoxide in the air (a few parts per million). Most CO monitors detect much higher concentrations of carbon monoxide (around 100 parts per million). When working in a place where carbon monoxide is a concern, such as in a home with gas appliances, be sure to use your instrumentation to measure CO in an occupied space. Also, check for carbon monoxide spilling out of the unit. Don't confuse ambient CO with the carbon monoxide found in combustion analysis; they are NOT the same. Ambient CO indicates a bigger problem like backdrafting. Unlike standard CO monitors, you will want to use a personal ambient CO monitor that can measure down to 1 part per million for YOUR safety. Again, do NOT use combustion analyzers for personal protection! You can also offer higher-quality CO monitor/alarm suggestions to your customers. 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, Michael Housh joins us to discuss his years of experience with geothermal heat pumps and their special considerations. "Geothermal" is a rather generic term, similar to how people say "Freon" to refer to any kind of refrigerant. Those heat pumps don't necessarily have to be underground; you can have water-source heat pumps in ponds or wells, and there are also ground-source heat pumps. The ground provides a steady temperature under many conditions, which helps heat pumps work effectively in cold climates. Like other heat pump systems, geothermal pumps come in split or package types. The pump may be either integrated with the equipment or separated from it. When the equipment is separate, multiple units can use the same loop (for example, a 10-ton loop can have five 2-ton units attached). Michael designs geothermal systems. He uses software to design systems, particularly closed-loop systems, and load calculations play an important part in informing his designs. Many contractors use rules of thumb to help size the loops, but the only way to know what you're doing is to take load calculations, especially on water-source pumps. Undersizing loops can severely reduce the system capacity and make it hard to maintain temperature. To keep performance up, we also need to flush heat exchangers as part of regular maintenance. However, restrictions and contamination tend to be relatively uncommon except in pump-and-dump systems. As with any type of equipment, be sure to follow the manufacturer's recommendations. Michael and Bryan also discuss: Patience and caring about outcomes of jobs Water temperature and quality effects on system operation Environmental concerns Maximizing efficiency in geothermal systems Geothermal sales and economic trends Return configuration Sharing loops Figuring out gallons per minute and delta T Pump-and-dump configuration Clogged heat exchanger symptoms Identifying problem areas Loop temperature variations 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 what water vapor diffusion is. He also explains why it matters to the everyday HVAC technician. Vapor diffusion is the transfer and distribution of water vapor through a solid surface. New constructions sometimes have vapor barriers on the outside of buildings in hot, humid climates or on the inside of buildings in cold, dry climates. (Even so, vapor barriers are not 100% effective.) We are NOT referring to water or mist wicking through the buildings via capillary action; we are referring to water vapor. Drywall, a common building material, is quite permeable and allows moist air to diffuse through it. The vapor diffuses through the drywall from the unconditioned attic to the conditioned living space. Of course, we have to focus on air sealing before anything else, but we also may need a vapor inhibitor or a means of controlling the attic dew point to prevent water vapor from moving through. The driver that causes moisture to move into the space is surprisingly NOT relative humidity. Instead, we need to focus on the actual moisture content as a driver, and it would help us more to look at the dew point. Dew point is the key to controlling vapor diffusion. If the dew point in the unconditioned space is higher than that of the conditioned space, then you will get vapor diffusion into the conditioned space. However, if the dew points are the same in the conditioned and unconditioned spaces, then there won't be a differential that would cause vapor to move. 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 live conversation, we discuss some real-life situations with difficult customers. We also cover some helpful tips we learned along the way. When Bryan started Kalos, there was one situation where a customer blamed him for lying about a customer diagnosis. So, that was how Bryan fired his first customer. However, many of us want to fire several customers, and that's when we have to look in the mirror and evaluate ourselves. When the problem truly isn't with us, we have to make a choice to say, "Sorry you feel that way," and walk away after we've tried our best. Sometimes, customers will demand that certain procedures are done or certain systems installed. Even if we were to give in to their demands, difficult customers would still be inclined to blame us, so it's up to us to assert our boundaries and do the job correctly. We also need to stop saying that our work is "easy." When we say that work is "easy," it appears to cheapen our work in the customer's eyes. We may encounter customers who are a bit neurotic or who want to take advantage of us. In those situations, the best thing we can do is take the customer seriously and take full responsibility for our work: carry out tests, answer questions, and solve the issue. The manufacturer may do very little to help a situation, so we must be prepared and knowledgeable. We also discuss: Bryan's Christmas pool heater meltdown Commercial HVAC/R finger-pointing Being "good with money" and how that translates to doing good business Valuing our work Working for family members and charging them A ductless disaster with a nervous customer "Calm down" Listening productively Setting expectations Pricing and making a profit Moving on from failing customer relationships Buyer's remorse 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, Henry Papa from Sporlan joins us in person to talk about refrigeration case controllers on systems with common compressors. We focus on the Sporlan S3C case controller, but some of the information applies to other case controllers. Case controllers control the conditions at each separate evaporator and are responsible for controlling defrost, discharge air temperature, and superheat. They can also monitor conditions at the evaporator, especially discharge air. In grocery, we tend to look at discharge air temperature instead of box temperature. Traditionally, we use EPRs to control a fixed evaporator pressure to control the discharge air temperature. With the S3C refrigeration case controllers, we can assess the discharge air temperature directly. The greatest advantage of the S3C controller is that it is NOT a single centralized control. Those standalone case controllers communicate with each other but work independently. So, if one rack goes down, the rest can keep running. On traditional controls, all of the racks could go down if one goes down. The S3C controller is also quite serviceable and connects to Bluetooth. So, you can sync the case controller display's data to your mobile device for convenient viewing. You can also control a few different functions from your device. However, you must take some time to understand the parameters, inputs, and outputs, as with any other controller. The goal is to read the manual and get comfortable with the details before working with the controllers. Henry and Bryan also discuss: Sporlan's podcast and training resources Parker-Sporlan relationship Demand defrost Alarm systems on refrigeration case controllers Dual-temp control Electronic EPRs vs. traditional EPRs Becoming "masters of the obvious" Check out Sporlan's Chill Skills online training 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 talks about brazing and soldering. He also weighs in on patching and if it is an allowable repair. Brazing is when you use a dissimilar metal to join metals at a temperature above 842°F, and soldering occurs at temperatures below that. (Welding occurs when you use the same metal as a joining metal.) In our trade, we generally use soldering on copper plumbing and brazing on line sets. We also often call brazing alloys "solders," such as silver solder. When making a joint, you want to have a sufficient (but not oversized) gap between the male and female surfaces of the joint. That's because the joint needs a large surface area where the solder or alloy can flow in via capillary action. Temperature is critical, as it needs to be high enough to draw the alloy into the joint, but it can't be too high. Patching is a controversial practice, but you CAN do it. If you are going to patch a system, it's best to do it on the low side of the system at a low temperature and with minimal vibration to minimize the risk of damage. Unlike traditional brazing, patching is when you use an alloy to seal up a small crack or leak; you don't want to draw the alloy into the joint. If you decide to patch, one of the best alloys you can use is 15% silver solder. You also risk blocking the tube. If you can cut the leaking section out and patch it with a coupling, that's an even better practice. We DON'T recommend patching on the discharge line at all. 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.

n this live podcast episode, we have a fun conversation talking with Nathan Orr and Kevin Compass about grocery refrigeration. The most common types of calls are those where the machine is "not making temp." Usually, the cases can't maintain temperature due to frozen evaporator coils or backed-up drains. On low-temperature/freezer applications, we must rely on electrical or hot gas defrost to mitigate frozen coils. Hot gas defrost is a complicated but quintessential part of low-temperature grocery refrigeration because the coils easily freeze. The discharge gas has to go to the evaporator coil and merge back into the liquid line; that gas CANNOT make its way to the suction line without causing damage, so the liquid line pressure needs to remain lower than the discharge line pressure. Kevin sometimes recommends running the fans all the time in open cases because the fans aid in the defrosting process, especially when it comes to warming the drain pan. Another common issue that refrigeration techs encounter is starved coils. Clogged TXV screens often cause starved coils, but we don't usually replace the entire TXV in grocery refrigeration. Instead, we only replace the part that needs replacing (the screen). The same practice applies to other TXV components; we replace only the powerhead if the powerhead has an issue. Most grocery refrigeration systems use refrigerants that are quite different from residential HVAC refrigerants. Some of the most common refrigerants are propane and carbon dioxide. However, propane is flammable, and CO2 doesn't work very well in hot climates. Nathan, Kevin, and Bryan also discuss: Electric vs. hot gas defrost Walk-in boxes Bunker cases/coffin cases Hoarfrost Water heaters Defrost termination Offsets and thermistors Underground line sets Charging refrigeration systems for a wide range of ambient conditions Ammonia refrigerant 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 Rothenberg and Ed Janowiak join Bryan to talk about the good, the bad, and the uncomfortable of ACCA Manual J, D, and S. Manual J load calculations exist to make the BTU inputs and outputs predictable. Then, Manual S comes in to assist with equipment selection to meet the load calculations and the customer's comfort needs. Manual D is a collection of mathematical formulas that exist to help you calculate your friction rate, which is important for comfort in terms of noise in the ducts (from excessive air velocity). Ed believes that the best way to learn Manual J is from the physical manual; several instructors will teach the calculations straight out of the book, not on computer software. The difficulty of learning Manual J is one of the manual's shortcomings. Also, while Manual D is often required by code, Manual J is not often required, meaning that technicians can get away with poor designs. A common argument against Manual J is that comfort needs also tend to vary with each customer; therefore, standardized calculations and targets may not help individual customers meet their preferences. The typical temperature and humidity targets are 75°F at 50% relative humidity. Under those conditions, the dew point is 55°F (meeting the 20°F delta T rule of thumb), meaning that the air should remain well above the dew point. When the air remains above the dew point, the risk of a moisture problem greatly decreases, even at the expense of comfort. Nathan, Ed, and Bryan also discuss: Bad square-footage rules of thumb ACCA Manual T (register placement) Temperature and humidity effects on comfort Oversizing equipment Single-stage vs. two-stage equipment Ductwork in unconditioned spaces Check out the ACCA website at acca.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 compares under load vs. bench capacitor testing to find out which testing method is better. When we test the system while the motor is running, we call that testing under load. Testing under load is fairly easy; you take the voltage across the capacitor (V), amperage off the capacitor's start winding (A), and then you use the following math problem: (A x 2652) / V (You can also punch those numbers into the calculator on the HVAC School app.) While you can test under load on an off system, the test will provide a more accurate picture of the operating capacitance if you perform the test while the system is running. On a bench test, you disconnect the leads, discharge the capacitor, and test it with a capacitor tester. The tester will charge and discharge the capacitor; then, it will measure the amount of current going into and leaving the capacitor. The voltage will be lower than on a test under load. If either of those tests yields vastly different results, then it's likely that one of your readings is incorrect; it's unlikely that the performance differs that much under load or on the bench. For example, some ammeters can read higher or lower than the true amperage value, which affects the total capacitance in the math equation. Capacitors merely have foil plating and oil to make them work. The attraction between those forces creates a charge. Normally, these shouldn't "overheat." The plate-to-plate surface area can break down over time, leading to poor capacitance. Capacitor testing gives us a picture of the capacitance, and the state of the compressor materials could provide an explanation for the test results. 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.

Eric Kaiser joins the podcast again, and this time, we are talking ECM motors. We discuss types, history, diagnosis, and failure prevention. An ECM motor has a permanent magnet rotor, which means that the magnetism never deactivates. The variable frequency-driven motor is typically an induction motor, and the rotor only becomes magnetized by the stator's field. Eric describes ECM motors as three-phase AC motors, but we can control the AC pulses, resulting in oddly shaped sine waves. Those motors essentially convert the AC power to DC power and then to controlled AC power with the help of a microprocessor that measures back EMF. ECM motors have been in the industry since the 1980s. General Electric designed them to put out a constant volume of air against a wide range of static pressures. As time has gone by, manufacturers have developed those motors to overcome a wider range of duct challenges. and to communicate with controls and display components. One of the most significant developments in ECM motor manufacturing was the constant torque motor, also known as the X13 motor. There are also constant speed and constant airflow ECM motors. When diagnosing ECM motors, you will want to be aware of the signals. The 24v signals work similarly on constant speed and constant torque motors but differently on constant airflow motors. Sometimes, only the module has an issue, which can be separated from the motor and individually replaced quite easily. Eric and Bryan also discuss: Modified or pulsed sine waves RPM as feedback PSC vs. ECM motor efficiency Temperature's effect on a motor's lifespan Achieving rated static pressure How moisture can impact motors Overvoltage events and motor failure Programmable speed taps Informational resources on ECM motors 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 lively discussion, representatives from Chemours and Bluon Energy join the podcast. They talk about retrofit refrigerants and what to look for in a good retrofit. The R22 phaseout has been on the agenda for a long time due to its ozone-depleting potential. However, R-410A is also due for a phase-down in the future due to its global warming potential. While neither refrigerant will be outright banned, we will have to consider alternative retrofit refrigerants in the future, especially if reclamation rates stay low. Almost all of the replacement options are refrigerant blends. When we deal with refrigerant blends, we have to think about temperature glide and oil return. Many of the R22 retrofit replacements are compatible with mineral oil, and that's because manufacturers add hydrocarbons, which are chemically similar to mineral oil. We try to avoid toxic (B) and flammable (2-3) refrigerants on the ASHRAE classification system, but the hydrocarbons add just a little bit of flammability to the blends (2L). Retrofit refrigerants also behave differently in the way that they transfer heat, as refrigerants with glide may be colder in the evaporator. They may run with exceptionally cold evaporator coils, which could be an issue in climates with a high latent load. At that rate, some airflow reduction may be necessary to prevent the coil from freezing. The Chemours and Bluon representatives, Eric Kaiser, and Bryan also discuss: Net refrigeration effect (NRE) Offsetting hydrocarbons Mineral oil return and velocity issues POE oil as a lubricant Latent heat of vaporization Retrofit refrigerants' heat transfer in the evaporator coil R22 pricing expectations post-phaseout Education and training for flammable refrigerants and blends Benchmarking equipment Manufacturing R22 replacements Off-grid refrigeration 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 discusses the importance of the trap and vent in condensate drains. He also describes some trapping and venting best practices. Anytime you have long runs of horizontal drains, you run the risk of having a double-trap. A double-trap creates a water seal, which traps air between the two traps and prevents a system from draining properly. To avoid the complications of double-traps, you can create a proper trap at the air handler. When making a P-trap, make sure the outlet is lower than the inlet; traps need some fall. Then, you would vent it. When creating a vent, make sure it has enough height to be higher than the pan. That way, it should take longer for the drain to overflow if it backs up. If the system has a float switch, that should be tripped before condensate can overflow from the vent. On RTUs, the cleanout is close to the unit, and the vent will go after that; RTU units can have shorter vents. Do NOT cap the vents. Some best practices to avoid double-traps include strapping the drain properly. PVC can be especially challenging because it tends to bow and bend over time. Location can also present challenges, as we run drains underground due to the building structures and geology in Florida, which can cause backups. However, in the end, the main goal is to create a drain line that prevents air from blocking up the drain and doesn't cause property damage when it backs up. 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 live podcast episode, Bryan talks through real home IAQ solutions with Jim Bergmann and others. They also answer audience questions. Indoor air quality is a place where the HVAC and building science industries intersect, so it is an important topic for occupant health and comfort. Home IAQ is much more holistic than UV lighting or ionization solutions. For example, duct leakage is one of the fundamental challenges of indoor air quality in the vein of controlled ventilation. However, some more advanced IAQ devices include particulate counters, which focus on tracking pollutants in the air and understanding how those pollutants work with relative humidity. Some common pollutants include pollen, dust, VOCs, dander, carbon dioxide, and carbon monoxide. While most of those are bothersome and may cause comfort or minor health issues, carbon monoxide is potentially deadly. Homes that use gas appliances must have appropriate venting (and proper combustion) to keep CO out of the home. VOCs and carbon dioxide are two IAQ villains that require ventilation to dilute them. When lots of occupants are in a space, the carbon dioxide load can get very high, and furniture, paints, and other household objects can off-gas VOCs. Ventilation also helps us control energy usage in a home. Relative humidity is another important IAQ factor, especially when it comes to sealing ducts and controlling ventilation. Sweating is undesirable in the home, and we don't want to drive indoor temperatures below the outdoor dew point. Bryan and Jim also discuss: MeasureQuick duct leakage test Return vs. supply leaks Aeroseal CO poisoning and testing Building pressurization and balanced ventilation How to use mechanical ventilation properly CO2 sensors Determining practical and impractical IAQ practices Carrier Infinity controls Reheat electricity and dehumidification Ozone Oversized air filters Discussing IAQ product maintenance costs with customers If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Craig of AC Service Tech on YouTube joins Bryan on the podcast to explain how to charge an A/C unit. He also discusses his excellent new book. Before you start charging a unit, you must know about superheat, subcooling, and other means of determining how much charge is already in the system. You must also know how the refrigeration cycle works so that you can tell if the system is operating properly. Other must-understand concepts are saturation and the pressure-temperature relationship. To start off, you'll want to pull the disconnect on the outdoor unit. Then, get information from the homeowner and check the airflow; check the filter and examine the ductwork before turning the equipment on and using an anemometer to check airflow. When you actually begin to charge the equipment, you want to screw on your hoses clockwise and read your pressures. After you read the pressures, push the disconnect back in. Monitor the low-side gauge and keep the saturated temperature in mind. Verify the metering device and refrigerant type. Your metering device will determine the charging method; you would use the total superheat method on fixed-orifice systems and the subcooling method on TXV systems. You use those values and compare them to the target values to determine if you are low on refrigerant or overcharged. Then, you add or remove the refrigerant accordingly to reach those targets. Craig and Bryan also discuss: Well-roundedness Sliding calculators Saturated temperature Service valves Superheat vs. total superheat Frozen evaporator coils Adding refrigerant at different points of the system Line set length Breaking the vacuum with refrigerant Refrigerant Charging and Service Procedures Check out Craig's YouTube channel 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 and nerdy science podcast, Bryan discusses how electromagnetism impacts every part of our lives. Electromagnetism refers to the movement of electrically charged particles. From transformers to the visible light that helps us see, the movement of electrons is a critical part of our lives. For example, light is an electromagnetic wave within the visible part of the spectrum. On the more complicated side, AC motors generate a rotating magnetic field, which generates electricity. Transformers can also step down or step up voltage via two electrical coils that transfer energy via magnetism; electricity moves on the other side. Electromagnetism deals in waves. The distance between these waves varies, and the space between each wave is called the frequency. Many radio stations nowadays rely on frequency for listeners to tune in, and you can fir several stations just between the values 88 and 108. With TV, you wouldn't even get a single channel in that range (88-108 is somewhere between channels 6 and 7 on the old VHF analog system). Frequency rates also dictate many properties of a wave. Radio waves and microwaves are on the low-frequency side of the electromagnetic spectrum, whereas ultraviolet and gamma rays are on the high-frequency side of the spectrum. Visible light is right in the middle, and frequency helps us determine which color we see. Waves move through a vacuum and can self-propagate, but old scientists believed that waves moved through a substance called the aether. Bryan also discusses: Hertz scale Electromagnetic vs. sound waves Electrons in chemistry and physics Atomic structure 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 first live podcast episode, Bryan responds to audience questions and discusses moisture and humidity issues in HVAC. Moisture leads to other problems, including fungal growth. We often see moisture problems where the surface temperature meets the air dew point, not where hot meets cold. When the customer drives the temperature down too low, many surfaces in the home can meet the dew point and begin sweating, especially ductwork in unconditioned spaces and air handlers. When you increase airflow, you derate the HVAC system's dehumidification. That's because the evaporator coil can't get cold enough for moisture to condensate on top of it, meaning that the moisture stays in the air. If there isn't enough dehumidification, we may end up seeing a moisture problem. These problems are especially prominent on wood and finished surfaces and can damage those severely. When assessing a home, you also have to think about internal moisture gains, including from cooking, showering, and doing laundry. However, external moisture gains are a major concern from infiltration. Drawing poor-quality, unconditioned air from attics and the outdoors through cracks will increase those gains. You must also keep in mind that the dew point can be different throughout the house. Dew point will also be different on the ceiling compared to the floor. Some stratification occurs with height, so that can complicate matters and must be accounted for. Bryan also covers: Multi-stage compressors Dew point vs. relative humidity Infiltration, leakiness, and negative pressure The problem with bath fans Water in slab structures Boot sweating R-value and insulation in the attic Commercial buildings with fresh air requirements Condensate blowoff in horizontal installations Dealing with wet insulation 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.

Eric Mele and Joe Shearer join Bryan to discuss the challenging issue of diagnosing and rectifying non-condensibles in the circuit. Non-condensibles are gases that don't condense, including nitrogen. These are NOT moisture or contaminants, and they can be tricky to diagnose; the pressure readings will likely be normal, but the charge will actually be quite low (around 60-75% of the usual charge). These gases also don't just enter the system suddenly in significant amounts; non-condensibles typically enter the system when lots of technicians work on it, or the gases have been there all along. One of the most telling symptoms of non-condensibles in the system is elevated head pressure and subcooling WITH flashing. (You can usually hear the flashing at the metering device if you listen.) Otherwise, the symptoms often mimic those of a metering device restriction, which is a much more common issue. The only real way to tell if you have non-condensibles is to weigh out the charge; you may recover the charge or pump down the system. When you come across a system with non-condensibles, the customer may merely notice decreased cooling performance for an extended period. However, when a system is allowed to run with non-condensibles for a long time, there will likely be some long-term effects on your system. For example, these gases can erode the needle on a TXV. Eric, Joe, and Bryan also discuss: Common misdiagnoses Metering device restrictions How metering device type affects non-condensible symptoms Liquid seals Pinching off the discharge line Copper plating on compressors Pumping down scroll compressors (and general pump down) Training other technicians to diagnose non-condensibles Liquid line and filter drier restrictions Long line sets and accessories 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 quickly covers defrost termination and failsafe. He also explains what they mean in refrigeration systems. We need to defrost evaporator coils anytime they drop below freezing (32°F, o°C). When evaporator coils have a coat of ice over them, they cannot transfer heat from the box to the refrigerant; the ice blocks the coil from the air in the box. In defrost, we add heat to the evaporator coil. We can add heat in the form of electric heat or hot gas (discharge gas); either of these can damage product if they run too long. A simple off-cycle defrost may also work on properly sized coolers and medium-temperature equipment. We can control defrost by fixing the cycle onto a timed schedule. Unless we can use a complicated algorithm with a series of sensors, we almost never initiate defrost based on temperature. Instead, we initiate defrost based on a timed cycle. The defrost termination relies on a thermostat or control to stop the defrost, so a defrost will end early based on a temperature reading (since it will be well above freezing). After the defrost ends, there may also be a dwell time where the coil can drain its moisture before the refrigerator starts cooling again; that way, the moisture won't freeze back onto the coil when the system starts operating again. If the defrost termination fails to kick in, we need to set a defrost end time to take the system out of defrost. We call that end time the failsafe. It is not a good idea to use the failsafe to predict the defrost cycles; it should only work in the case of emergencies. So, to sum things up, defrost termination relies on temperature, but failsafe relies on time. 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 joins us to talk about testing oil and refrigerant for contamination. He also explains what each test is good for. John developed the Checkmate testing kit when he recognized a need to test reclaimed and recycled R-12 for acid and moisture. The Checkmate method removed a small amount of refrigerant from the system for testing. The Checkmate apparatus hooks up to a refrigeration system to test the oil. You insert a tube with a rubber stopper, and you can draw refrigerant from the system when the tool pierces the rubber stopper; the method is similar to drawing blood. The kit then assesses the acid content in the refrigerant and creates a colored stain that indicates the acid content. You can use an included color chart to interpret the stain color. Checkmate also assesses oil based on its dielectric strength; contaminants can give oil conductive properties, which the test picks up on. Unfortunately, oil breakdown can happen even when technicians use best practices, and it's commonplace on aging systems. Some tests only pick up on acid, not moisture. However, Checkmate picks up on the moisture content as well, which can be an indicator of future acid problems. Many technicians don't perform oil testing frequently enough; if they test the refrigerant or oil at all, it's only infrequently, such as during PMs. More frequent testing could occur with easier testing methods, such as by using the Checkmate kit, and it could save HVAC system owners lots of money in the long run. John and Bryan also discuss: Diagnosing compressor burnout Conductive oil Gradual oil breakdown Schrader core testing devices PVE oil Air and moisture skewing other test methods Vapor testing Venting exemptions for acid/moisture testing (de minimis) Checkmate tube shelf life Suction driers 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 what to do when you get water in your tools. (Hint: the answer is NOT to panic!) Some technicians try not to get water in their tools at all. Depending on the climate and line of work, that may be an impossible task. In humid or coastal climates, you may deal with a lot of rain and moisture. If you work on cooling towers and boilers, you will be working with systems that rely on heat transfer through water, so you WILL encounter water. When your tools get wet, you can't just stick them back in your toolbag and pretend that nothing happened; the tools' performance WILL suffer if you don't address the issue. If your tools get water on them, they won't dry on their own; they will corrode. At Kalos, we use microfiber cloths to clean our hand tools after they get wet. In the case of battery-powered tools, make sure you remove the battery and dry it off as best as you can. Sometimes, you can use WD-40 to help displace water. You can also look into using degassing chambers to remove moisture from battery-free tools. These chambers look like crockpots and make it easy to pull a deep vacuum (below 500 microns) to remove moisture. (Don't put batteries or devices with refrigerant in the degassing chambers! Cell phones fall into this category, too!) 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.

Mike Hardy from SpeedClean joins us to talk about how SpeedClean got started. He also explains why all contractors should consider engineered solutions. SpeedClean emerged from the need to make coil-cleaning a better experience. Mike's philosophy is to look at the "pain points" of common tasks so that his company can develop engineered solutions to reduce the issues of those "pain points." The goal of companies like SpeedClean is to make an HVAC job more efficient to boost technician productivity and provide good value. However, Mike also believes in consumer education to promote user adoption, and he wants to make sure he conveys the benefits of SpeedClean equipment. In the past, pressure washers were some of the only technologies available to clean coils well enough, but they often damaged the fins and led to unhappy customers. There also weren't many pump sprayers, and hoses weren't always long enough to reach the equipment. So, the CoilJet came into existence in 2007 and had a mostly positive reception on the US West Coast. Customer feedback helped Mike improve his product, and he continues to accept and integrate user feedback today. As mini-split systems began to emerge, a need to revolutionize indoor cleaning emerged. So, SpeedClean released the Mini-Split Bib Kit to make indoor ductless cleaning easy and mess-free. SpeedClean makes all of its products in the USA, and its company culture places a high amount of value on the employees and respects their life outside of work. There is an assembly-line-type methodology in place, and the company consistently meets demand. Mike and Bryan also discuss: Battery issues with the CoilJet Negotiating labor and product costs CoilShot evolution User adoption and "laggards" Systems thinking Cleaning efficiency best practices Learn more about SpeedClean HERE. You can check out the HVAC School and SpeedClean mini-split cleaning guide HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Eric and Bryan talk through some non-standard ways of thinking about filter drier usage. They also discuss how to install these non-conventional filter drier ideas. The humble filter drier helps us prevent gunk from moving throughout the refrigeration circuit with the refrigerant. That way, you protect the compressor and metering devices. Ideally, Eric would install his liquid line filter driers right before the metering device, but that's not always practical. When you put a suction drier into a commercial refrigeration application, most people will want techs to remove it. Suction driers can drive up the compression ratio by creating a pressure drop, which is undesirable. However, Eric likes to leave the drier in the system if it won't impact the system efficiency too negatively. Replacing the suction drier is especially important in the case of compressor burnout or acid in the system. If you have an accumulator, it is best to replace it in the case of burnout; you will also want to install the suction drier near the compressor, which will help prevent or reduce accumulator damage in the case of burnout. Above all, when you add driers to the system, you want to put them in sensibly. Their goal is to protect the system, and their sizing and placement should help them do their job. Also, DO NOT put filter driers in the discharge line! (Yes, it happens.) Eric and Bryan also discuss: Lennox liquid line drier placement Factory driers Replaceable core driers Flares, ball valves, and bypasses Using check valves on heat pump systems Testing oil for acid and burnout Undersized filter driers Factoring material pricing into proposals and quotes Discharge mufflers vs. filter driers 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, Bryan discusses the recent ads and news articles claiming that homeowners are in trouble and that R22 is becoming illegal. The R22 phaseout has been on the agenda for a long time and will finally come into effect in 2020. HCFCs have ozone-depleting potential, and it is time to look at more eco-friendly alternatives, such as R410A and R407A. The phaseout has affected prices and will cease virgin refrigerant production. However, after the phaseout period begins, R22 will NOT become illegal; you will still be able to find it in supply houses for a while. Nevertheless, you will only have access to recovered stock, and the costs may go up as the supply depletes. It is also NOT illegal to recharge systems with R22 as long as the refrigerant charge is under 50 pounds. You also still cannot vent or import R22. Overall, the AHJ may make different rules, but the EPA is not making the refrigerant illegal. Customers need not worry about replacing their air conditioner. There may be benefits to replacing an air conditioner, such as efficiency gains. However, there is no legal reason for customers to worry about replacing their systems. As HVAC technicians, we should focus on repairing leaks on R22 systems for customers who do not want to replace their systems. The most important thing to do is be honest with the customer; you can ease their worries about the legality of their system. However, you can still be honest about the environmental impact if the customer expresses concern about that. Check out The Engineering Mindset's YouTube channel 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.

My buddy Eric Kaiser from the ETS Group comes on to discuss a common problem we see in both students and techs as they study. We talk about issues with how they think about the trade and how to progress in it. Eric noticed that people who take classes or plan to get certified tend to study just for the end test. The tests may be industry-standard, but the students and technicians don't learn to apply their knowledge; they merely learn with the goal of passing the test. Many technicians look for courses to complete. Instead of absorbing information from articles and videos, people want their knowledge to be verified. As a society, we put so much value on completing academic programs. The truth is that learning is continuous; you don't suddenly need to stop learning once you complete a course, obtain certification, or pass a test. For schooling and study practices to be truly effective, the student or technician needs to have a mindset focused on applicable skills. In hiring, we should focus on the applicability of an applicant's skills. Instead of using a written test or relying on a resume, a physical assessment would be a much more useful hiring tool for HVAC/R job interviews. HVAC/R jobs have significantly more difficult physical "tests" than a mere certification exam: work ethic, working under pressure, solving problems, and applying best practices. Studying for an institutional test won't help technicians or students who want to get into the field. Eric and Bryan also discuss: Eating healthy on the job Certification tests Interest-driven homeschooling vs. test-driven public schooling Test-taking talent vs. applicable skills Communication and customer service skills Purging hoses and other best practices Society's overemphasis on degrees and certificates Benefits of traditional testing Willingness to learn 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.

Balancing complaints are common in the HVAC industry. In this short podcast, Bryan explains how diagnostic duct design solves those issues. "Diagnostic duct design" refers to using the duct system to locate and solve a customer's comfort problems. If a couple of rooms have problems with humidity control, then the duct system could be a culprit. However, before we even touch the ducts, we should look at the space to determine if we have issues. For example, radiant gains from a window could be contributing to comfort problems, not the duct system. Airflow may also not be an issue if comfort at night is an issue. That's a matter of the equipment cycling less often at night, and we can solve that by reducing the setpoint at night. When we look for duct issues, we want to assess the pressure. You can do very simple tests with a manometer (or a qualitative test with tissue paper under a door crack) to look for pressure imbalances, which can cause discomfort in rooms where the door is closed very often. Flow hoods are good for assessing airflow, but you can also get an airflow approximation by measuring air velocity. Make sure you're hitting your targets; then, you can check your static pressure. Since distributed airflow is a major comfort factor, you can take the total CFM and divide it by the square footage (factoring in each room's square footage) to determine the airflow distribution. Remember: Perimeters require more airflow than the centers of rooms, and rooms with more windows will have greater radiant gains to account for. When you can't redesign the entire duct system, use balancing dampers in oversized ducts to help balance the airflow. (Make sure the register isn't oversized, though! Try to keep the static pressure down, too.) 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.

Eric really likes ceiling cassette air handlers, so much so that he put them in his own home. We discuss ceiling cassettes vs. highwall and other ductless-related topics. A cassette air handler looks like a concentric fitting, and they are generally installed in acoustic or drop ceilings. Eric likes the comfort and easy installation. However, people who have low ceilings or dislike exposed equipment may not like ceiling cassettes as much as Eric does. Both cassettes and highwall ductless units work well in sunrooms or lanais, but Bryan has noticed that cassettes seem to provide fewer problems than highwall ductless systems in that market. Eric has noticed substantial differences in the cleanliness of cassettes and highwall systems. He noticed that the cassettes don't get nearly as dirty as most highwalls, and highwall systems are difficult to clean. However, some of those cleanliness issues may have something to do with VOCs, pollutants, and climate. Highwall ductless units require separate condensate pumps that require a lot of maintenance and a gravity drain. Ceiling cassettes have condensate pumps that may either run continuously or on-demand. Cassettes' condensate pumps are also easy to access for cleaning, and they are a lot quieter than the pumps on ductless units. The drain pan is also easy to pull down, though Eric has yet to need to clean his cassette's drain pan. Although ceiling cassettes appear to have several advantages, price is not one of them; they are typically more expensive than highwall ductless units. Eric and Bryan also discuss: Blower wheel cleanliness issues in highwall systems VOCs and air pollutants Drain pitch and insulation Gravity drains Eric's cassette installation New Carrier and Mitsubishi products 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 breaks down the most common defense for bad practices: time in the industry. He also explains how to STOP USING IT as an excuse. When technicians communicate with each other, especially online, they tend to justify their practices with the phrase, "I've been doing this 30 years!" What they don't realize is that their old training (and habits) don't reflect the current state of the industry and the current standards of best practices. When technicians spend so many years in the field, they may justify bad practices by saying that they've always done a task a certain way. However, as practices evolve in the industry, time becomes less relevant as former practices fall out of favor. For example, beer-can cold is no longer an acceptable means of determining the suction line temperature. While former practices may have helped technicians get an A/C unit to blow cold air, those practices hardly optimized performance. The goal of training nowadays is to teach technicians the best practices to optimize their customers' systems. IAQ and customer service are also much more important in our industry today. The HVAC industry has also evolved a lot in terms of equipment, refrigerant, and oil. In the past, refrigeration systems didn't have to worry about oil conversions because we used different oils and refrigerants. Practices that we used 30 years ago are no longer applicable; technology has passed those practices by. Nowadays, we would be best off if we paid attention to new training and best practices. We must admit what we don't know and be willing to learn more about the technology our industry relies on today. Listening to others is how we will improve, not stubbornly defending our bad practices by saying how long we've worked in 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.

Devin Skipper comes on the podcast to give you an introduction to make-up air systems and explain their purpose. This time, we pull out all of the initials: MAU, MUA, DOAS, and MHGRV. Make-up air is outdoor air that we bring in to replace exhausted indoor air, usually in commercial systems. We use dedicated systems to bring in humidity-controlled air to rebalance the building to a positive pressure; hotels, restaurants, and medical facilities with significant exhaust need fresh air to compensate for that exhaust and negative pressure. Unsurprisingly, design is critical for these systems, especially in humid climates. For example, in a restaurant, fresh air must come in from an area where it can add positive pressure without too much humidity. So, exhaust devices AND make-up air units will be on the roof. Undesirable infiltration occurs through cracks and under doors and usually isn't enough to make a satisfactory difference in the building pressure. In commercial facilities, excess negative pressure can make it difficult for people to open doors, which could present a safety hazard for building occupants. MHGRVs (modulating hot gas reheat valves) modulate discharge gas through a reheat coil. These components allow a system to keep running and maximize dehumidification without overcooling the space. When a reheat valve opens, the condenser valve closes and redirects discharge gas to the reheat coil, but they are NOT the same parts that facilitate hot gas defrost. These also keep systems from tripping on high head pressure. Devin and Bryan also discuss: High-latent markets and design conditions Measuring pressure (in wc) Excess positive pressure complications Floor drains and negative pressure Reheat strategies MUA fans vs. units MUA controls Learn 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 multi-stage or variable-speed compressors. He also explains the impacts of staged compression. Multi-stage (or variable-capacity) compressors can come in many different forms, but they all have one thing in common: they can adjust their capacities. We typically rate equipment for its maximum capacity. However, when you vary the capacity, you get turn-up or turn-down; the refrigerant mass flow rate increases or decreases. When a unit turns down the capacity, the output decreases; the blower should also reduce its CFM output accordingly. While the compressor staging can vary, the coils and metering device stay the same, so the system must handle staged compression. We sometimes have to pay extra attention to the metering device to make sure the system operates as it should. When we decrease the compressor capacity, the suction pressure goes up while the head pressure goes down; the pressure differential depends on the refrigerant flow. You'll also run a lower condensing temperature and higher evaporating temperature. However, if the blower adjusts its CFM output with the turn-down, these effects will be less significant. With a higher evaporator temperature, we can expect a warmer evaporator coil, which will decrease dehumidification. Since our compression ratio will be lower, you can expect some efficiency gains during a turn-down. You can also expect lower amp draws. We can control capacity and reduce it without having to worry about short cycling. When you turn up a compressor, as you can on some ductless systems, you can expect the opposite effects of a turn-down: higher head pressure and lower suction pressure. Bryan also discusses: Variable-capacity compression in ductless systems Approach temperature Turn-down rate on equipment 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 Bergmann is back on the podcast to talk about the effects of dew point on coil TD. He also gives us a full rundown on recent MeasureQuick updates and what to expect in the future. When you see flags in MeasureQuick, those indicate symptoms of specific problems. MeasureQuick cannot outright diagnose equipment; it can only offer variables and educate the user based on the symptoms it notices. Red flags are major faults, and yellow flags are minor faults or functions of the installation (such as long line sets), but Jim wanted to make the flags communicate information more effectively. While Jim Bergmann worked on the sensible and latent targets, he learned more about the relationship between the dew point and coil TD. In high-humidity conditions, dropping the airflow and dew point temperature can overload the coil with humidity enough to affect the DTD by a few degrees. So, Jim had to tweak the MeasureQuick algorithm to account for those conditions. When water is on the coil, a lot of heat transfer occurs because water has such a high specific heat value. The compressor can't keep up, and you can experience high suction pressure and high discharge pressure in high-latent conditions. The increase in suction pressure drives up the TD. MeasureQuick has recently focused on defining targets, making the app work with new probes, and working on a cloud service that allows the user to store information, share data, and benchmark systems. Jim and Bryan also discuss: MeasureQuick feedback Sensible and latent removal targets Relative humidity and dew point Diagnostic algorithms and variables Communicating information through a rapidly developing app MeasureQuick cloud service Monetization High airflow and duct leakage scenario 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 talks about EPR and CDS valves. We consider both to be evaporator pressure regulators, but they really function quite differently. CDS are Sporlan components that appear to be quite similar to evaporator pressure regulators (EPRs). EPRs go in the suction line and control the evaporator pressure. The pressure and temperature relate to each other, so the goal is to keep the evaporator from freezing by controlling the pressure. However, EPRs rely on a pressure drop across them to be able to do their job, so compression ratios will increase, impacting power consumption. We primarily see EPR valves in supermarket refrigeration on rack systems. Electronic EPRS (EEPRS) include the Sporlan CDS valve. However, EEPRs do NOT actually measure the pressure in the evaporator coil in the same way that a standard EPR does. (However, they are evaporator flow regulators.) The pressure of an EPR is fixed via mechanical parts, but the CDS valve relies on a signal from the controller to set targets depending on the air temperature. The CDS valve can modulate via a stepper motor to maintain a certain target. Sporlan CDS valves have a lot of benefits. For example, you can reset or adjust the CDS valve without manually adjusting it; you can easily adjust the controls. CDS valves also don't require a pressure drop because they do not rely on a mechanical process to work. If you encounter modulation issues with your CDS valves, you can power cycle them. Sporlan SORIT valves have a separate solenoid, but the stepper motor allows the CDS valves to close fully. Overall, CDS setups can save a lot of energy and are quite easy to use because of their integration with controls. Unfortunately, they are prone to failure from power surges. 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 talks about dew point, bubble point, and midpoint in refrigerant blends. He also covers the purpose of each and why MeasureQuick displays midpoint on the gauges. We've formerly used mostly pure refrigerants. However, as new refrigerant blends come on the scene, we have to deal with glide, which indicates that we have a range of boiling temperatures instead of a fixed boiling point. We have bubble point and dew point, which are when the refrigerant starts to boil and finishes boiling, respectively; you generally use dew point to determine the superheat and bubble point to determine the subcooling. Zeotropic refrigerants have larger glides than near-azeotropic refrigerant blends; azeotropes have no glide at all. The midpoint is the halfway point between the bubble point and dew point in refrigerant blends. Coil temperature typically corresponds with the midpoint. To find the midpoint of refrigerant in the condenser coil, add the dew and bubble points and divide the sum by two. The process is a bit trickier on evaporator coils. In the evaporator, you run refrigerant through the metering device and get some flash gas; when the refrigerant undergoes that change, the bubble and dew points change. As a result, the midpoint becomes a bit more weighted towards the dew point (60%). In MeasureQuick, the temperature-pressure charts go a step above and beyond to give you the superheat, subcooling, and midpoint. The midpoint is the effective temperature of the evaporator coil, which is a critical piece of information in refrigeration systems where food products are at stake. You can also use the midpoint for coil DTD and TD. Jim and Bryan also discuss: R-410A and near-azeotropic refrigerants Metering devices as reactive components Coil temperature misconceptions and uncertainty Pressure differentials and drops in the system Maintaining food quality in refrigeration MeasureQuick mathematical models and formulas 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, 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.