HVAC School - For Techs, By Techs

Russ King joins us to discuss simplifying duct design for residential contractors. We focus on using 3D software for duct modeling. While computers are great tools for duct design, you must be careful with them. Computer technology doesn't correct your mistakes; it allows you to make mistakes more quickly. Russ made 3D software specifically for duct modeling, and its goal is to help technicians/contractors with duct designs and equipment sizing. The software is good for quick duct design, can determine flex duct design, and is ideal for broad usage in residential HVAC. Russ has noticed that existing energy modeling and load calculation software ask for extremely specific inputs, which can confuse technicians. He was frustrated with the process and wanted to make software that could help technicians solve the problems that mattered in a way that made sense. With the help of his son, Russ came up with Kwik Model (of Coded Energy). They developed software that allows users to design ducts and adjust parameters easily. The goal is for Coded Energy to be a simple, straightforward duct design software that addresses the hardest duct design issue: making the ducts fit. Coded Energy is written in Unity, which is used for video games and architecture/automotive design. The user essentially imports a floor plan, scales it, places boxes, and stretches the boxes to meet the design conditions. Once the user has built the house, the software can calculate the surface area automatically. Then, the user can use EnergyGauge for load calculations and equipment selection. The user can then draw ducts and have the software size the ducts for them. Russ and Bryan also discuss: Equipment selection for latent removal capacity Oversizing issues Designing ducts for building plans Comfort diagnostics 2D vs 3D modeling Getting feedback in the field post-design Visit kwikmodel.com to learn more. Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Bill Spohn with TruTech Tools joins us to talk about why being "approximately correct" is better than being "exactly wrong" when it comes to test instruments. When you see a number, that doesn't necessarily mean that you're dealing with a number you're supposed to see. For example, nitric oxide can present as "false CO" to a carbon monoxide sensor. Test instruments that mistake nitric oxide as carbon monoxide will give a different reading than ones that don't pick up nitric oxide as CO, but that doesn't necessarily make either of them wrong. So, some instruments can give you false positives based on exactly what they measure. On the other hand, false negatives may have to do with poor sensitivity. A common case happens with leak detectors; on occasion, a leak detector won't be sensitive enough to pick up a leak. You can't just say that a set of numbers on an instrument absolves you of responsibility for errors; you must understand the instrument, what it measures, and its sensitivity to use it appropriately. Being rigid in terms of specifications is also a mistake when communicating with customers; customer satisfaction is the goal, and it's okay if their comfort needs deviate from the specifications a bit. Overall, accommodation and mental/financial investment in your tools are the keys; for the sake of the customer, we need to make acceptable compromises, and that's something you must factor into your measurements. Bill and Bryan also discuss: NOx filtration Bacharach PGM-IR Personal protective CO detectors and overloading Laboratory-grade instruments vs. normal test instruments Getting valid wet-bulb readings and using sling psychrometers Analog gauge variables and inaccuracy Lab testing and controlled conditions Ductwork in conditioned spaces Flow hoods Using our senses Olfactory fatigue 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.

Bernadette Shahin of Aeroqual joins Bryan and Kaleb as they all dig very deep into indoor air quality (IAQ) sensors and instruments. They also cover the certainty and uncertainty of measurements. Reference method instruments generally have to operate within a set of parameters, notably a temperature range. Gas laws make the gases act differently, so you want the temperatures and pressures to stay within a range that allows you to measure the air conditions effectively. While we can use reference methods for full-scale instruments, there are no reference methods for IAQ sensors. The only way to make something close to a reference method on IAQ sensors is to use the near reference method. We measure humidity and temperature, and we do an atmospheric chamber and calibration. You have to pair sensors within an instrument to have a product that properly senses conditions. Measuring indoor air quality is important because we spend 90% of our time breathing indoor air with very little fresh air. Air pollutants build up in indoor spaces, and you could spend time in environments with harmful VOCs, allergens, and bacteria. Most people don't have the means of using HEPA filters or fresh air mixing in their homes; so, we need to focus on other solutions to control indoor air quality. Those solutions include air purifiers, but they also include sensors that monitor the air quality. One such sensor is the photoionization detection (PID) VOC monitor. With sensors, we must also think about sensitivity; we want the sensor to measure what it's supposed to measure in the amounts it's supposed to measure. Bernadette, Bryan, and Kaleb also discuss: Barometric pressure instrument calibration Algorithmic adjustments Sick building syndrome Formaldehyde off-gassing, ozone, and CO Aeroqual's solutions for BTEX Automatic baseline correction R2 factor AQI Automating IAQ strategies Pricing 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.

Jordan Cummings is back to discuss some of the most important points in the proper installation of VRF and VRV systems. We especially cover piping best practices. When it comes to piping, the biggest concerns on VRF and VRV systems are making sure the piping can handle the refrigerant velocity and ensuring proper oil return. Most VRF systems use PVE oil, but you still want to be cognizant of oil type, as not all manufacturers use PVE. You must consider fittings, length, and elevation changes when you pipe a VRF or VRV system. In our suction line, we want minimal pressure drop because too much suction drop reduces the mass flow rate through the compressor. You also need to think about avoiding too much of a pressure drop on the dual pressure line when it sends refrigerant to the compressor. You want your piping to be below the connections on the outdoor unit. The piping should be pitched up towards the unit when the outdoor unit is elevated on a stand. Of course, you'll also want to be mindful of where you place the outdoor units; the units should avoid the elements and be mindful of any awnings above. VRF/VRV systems come together at a variety of joints, including REFNETs and wyes (multi-chassis kits). Indoor units use REFNETs, which are basically engineered, balanced wyes. Outdoor units use typical wyes. Positioning these joints also makes a huge difference when it comes to proper feeding. Jordan and Bryan also discuss: Pipe sizing with software Dual pressure line PVE vs. POE oil Miscibility and oil carry Air-cooled vs. water-cooled condensers Condensate drains and trapping Reduced pumping/flow on water-cooled condensers External static pressure Alarms Piping limitations Cross piping on the branch selector box Expansion valve staying shut Pipe expansion 550 PSI, 24-hour pressure test Testing as you go Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Bryan and Eric Mele have a relaxed conversation on time management on the job. They also explain how to manage time in life as a whole. Some people are naturally fast because they cut corners in the name of time management. Instead, something Eric has learned to do is optimize his processes. He gets his work done a lot more quickly because he knows how to get the most out of the trips to his truck. Eric is also familiar with the tasks to perform them confidently, and he knows which diagnostic tools he'll probably need. Overall, repetition leads to efficiency. There are also plenty of ways to streamline evacuation and recovery. For example, Eric recovered refrigerant by piercing the liquid line from the air handler. His setup consisted of two charging hoses, a line dryer, and a recovery machine; it was an economic way to save his tools and recover refrigerant in the rain. Eric has done a lot of installs with people of varying experience levels. If there's one thing he learned, it's that you can streamline the process by starting at the outdoor unit, getting the old unit out, and getting the new unit set. The entire time, only one person should be working on the one-person jobs while the other gets supplies and makes preparations as needed. When it's time to work on the new unit, one person can work outdoors while the other works indoors. Eric and Bryan also discuss: Diagnostic tools to keep close or go without Dealing with paperwork Scavenging and saving small parts Cleaning the drain pan Pulling a vacuum through difficult fittings Working with people of diverse experience levels Using tin snips Efficiency and payment Work-life balance Prioritizing parts of your life Working with cranes 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 suction line traps and inverted traps are. He also covers the purposes they serve. It's a bit hard to find literature on suction line traps, so it's always best to read the manual and follow the manufacturer's guidelines. We traditionally use P-traps on suction lines to hold oil and let it go up the walls of the refrigerant piping. You need enough velocity to lift oil (mineral or alkylbenzene) up the riser. We know that POE carries much easier with refrigerants than mineral oil; it is very miscible with common refrigerants. That's why it's especially important to get all of the mineral oil out of retrofit systems. In refrigeration, we have lower temperatures, pressures, and densities; that combination adversely impacts oil carry. Oil logging is a bigger concern even with POE oil. So, P-trapping with POE oil is a more common practice in refrigeration than it is in air conditioning. In air conditioning, we can make a case for the inverted trap: in an air handler that's higher than the condenser, we want the suction line to go above the air handler and then go down into the evaporator coil. When the system goes off, there is still refrigerant in the evaporator coil, so refrigerant will condense into a liquid. We don't want that liquid to rush down the suction line and into the compressor upon startup, so we use an inverted trap to prevent flooded starts from happening. However, we can use hard shutoff TXVs and other strategies to prevent liquid refrigerant migration. Unfortunately, inverted traps can also keep mineral oil stuck in the evaporator coil. 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 how you can prevent and overcome price objections in your HVAC business. You can prevent price objections by avoiding the "budget" reputation. If your company establishes itself as a "budget" or "cheap" company, you will attract coupon-clipper customers. Coupon-clippers can be difficult to work with because of how cost-conscious they are. Customers who aren't looking for a deal will be less likely to object to pricing. You also don't want to shy away from money conversations with friends or family members. Once you get your business model and clientele established, you need to overcome pricing objections in yourself. "Expensive" isn't the issue; value is. If you set a price, then you need to be confident in it; pricing is a business decision, not a moral imperative, and you won't please everybody. If you're not comfortable with the prices, your discomfort can show in your body language and turn the customer away. Another tip is never to talk down your own value or make your work seem like it should be cheap; don't be afraid to explain labor or warranty costs if the customer asks. You can also prevent price objections by avoiding dramatic language. Instead of saying, "This will be expensive," or, "I've got bad news," you can just give the facts and the quote. If the customer gets emotional, you can empathize with them and give them a positive outlook on the situation. It also helps if you can keep money conversations as comfortable, clear, and fact-based as possible. Make sure you get customer approval and allow your customer to decline new procedures every step of the way. Bundle in extra value if you can. Oh, and remember to be empathetic and do a good job. 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 explains why latent capacity is prone to disappearing. He also explains what actually happens when the latent capacity drops. When you measure enthalpy split across the coil, you'll learn that the equipment design makes it perform to AHRI design conditions. Those design conditions are 95-degree outdoor temperature and 80-degree indoor temperature at 50% indoor relative humidity. So, the A/C system must remove a lot of moisture. However, we don't usually run A/C units for 80-degree indoor temperatures; we usually aim for a 75-degree indoor temperature. When we have 80 degrees, the sensible AND latent heat loads are higher. Things get tricky when we encounter disappearing latent capacity, which is when you remove less moisture. If we have equipment with a sensible heat ratio (SHR) of 0.75 at design conditions, we'll likely have a higher SHR with our typical conditions. When the dew point is lower, water condenses on the evaporator coil at a lower temperature; water holds up the surface temperature of the evaporator coil and optimizes heat removal, suction pressure, and compression ratio. When heat transfers to the water on the coil, the sensible heat in the air decreases via a latent process. When we don't have moisture on the coil, all of the heat going from the air into the refrigerant is making it in via conduction through the metal coil walls. Unless the coil gets below the dew point, it won't remove any moisture; we can still remove sensible heat, but you don't have the advantage of the moisture "holding up" the surface temperature. In very dry climates, we increase the airflow because we don't want to remove moisture from the air, but we still want heat to be available to the evaporator coil. However, we have to be careful about the bypass factor. 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, Jeremy Smith joins us to discuss demand cooling in low-temperature applications that use R-22 refrigerant. R-22 is NOT an ideal low-temperature refrigerant because it leads to high compression ratios. The discharge gas also gets really hot and can burn up the oil in the system. (The head of the compressor is even hotter than the discharge line, so if the temperature is high enough to cause oil breakdown in the discharge line, it's almost surely worse inside the compressor). However, R-22 is starting to go away in rack refrigeration. Demand cooling injects saturated refrigerant into the compressor to help mitigate the high discharge temperature and oil damage. It may seem like demand cooling intentionally slugs the compressor. However, the saturated refrigerant should boil off almost immediately, and it should not make it to the head of the compressor under typical conditions. On the diagnostic and repair side, demand cooling is usually pretty straightforward; if a sensor fails, then it's likely a thermistor issue. In the case of thermistor problems, you can diagnose those issues with the information given in the application engineering bulletin. Loose connections and valve restrictions can happen, but those are also pretty easy to diagnose and repair. Perhaps the most complicated issue occurs when rack systems have low liquid levels. The injector valves can't get a solid column of liquid, but many other components will work fine. Demand cooling solutions are usually brand-specific; each manufacturer has a slightly different setup. To learn more about the Copeland Discus compressors with demand cooling, check out the AE4-1287 bulletin. Jeremy and Bryan also discuss: Outdoor air and head pressure DTC valves Desuperheaters and hot gas bypass Tube-in-tube heat exchangers as "subcoolers" Seasonal changes in discharge temperature Why should we pay more attention to discharge line temperature? Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Bryan and Kaleb cover the basics of low-voltage electrical applications. They focus on the practical stuff, not just the theory that confuses techs. Many techs have a hard time with low-voltage electrical concepts and components because it's not easy to visualize what happens; we only see wiring diagrams, not metaphors that help us understand what's going on. The low-voltage control circuit starts with the transformer. The transformer has a primary side (where the high voltage comes in) and a secondary side (where the lower voltage comes out). The secondary is only connected to the primary via electromagnetism; it helps to think of the secondary as an independent electrical circuit. Color coding is a simple concept, but it has changed over the years and can confuse techs. You can only truly understand the wires by doing a complete visual inspection and tracing the wiring. (Though generally, blue will be common/C, and red will be hot/R.) We also typically use yellow for Y1, but Y is a confusing concept. Y ISN'T the compressor or cooling! Y pulls in the contactor coil; it is really the high-stage contactor. Y2 is a higher staging, and Y1 is a lower staging. On heat pumps, the white wire is usually for heating, and the orange wire is usually for the reversing valve. G is for the indoor fan and often has a green wire. Kaleb and Bryan also discuss: Tapping transformers W and O calls on heat pumps G calls DH on 24v controls Communicating controls Float switch configurations and issues Breaking Y or R with the float switch Wire routing: air handler and condenser Preventing conductor corrosion NASA or lineman splice Stranded shielded wire vs. solid wire 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 talks about the impacts of compression and airflow changes. He also discusses some of the ramifications of those changes. In order for us to energize the second stage of a compressor, we need to energize both Y1 AND Y2. On stage 2, we're running that compressor at full speed (350-450 CFM per ton). The compressor will also perform at rated capacity. When you stage down to stage 1, your blower should ramp down, and the compressor should produce less capacity (move less refrigerant). When moving less refrigerant, the compressor should use less current but still be cooled properly. Naturally, the suction pressure goes up while the head pressure goes down when we ramp down the compressor. However, when you reduce the blower speed at the same time, your evaporator coil picks up less heat. In that case, the suction pressure would drop. You normally don't want the suction pressure to go up in the low stage from the high stage. The impacts of compression changes are multifaceted, and there are several moving parts to think about when it comes to capacity. When the compressor slows down, it moves less refrigerant over the same period of time; your compression ratio goes down if your airflow over the evaporator coil remains the same. However, if the airflow drops proportionally, then your suction pressure should stay close to the same. If the compressor pumps the same amount of refrigerant, the suction pressure will drop. If the compressor pumps less refrigerant proportionally to the airflow, then the suction pressure should remain the same theoretically, but it usually increases. An increase in suction pressure results in a lower compression ratio, which is good for efficiency. Bryan also discusses: Floating the evaporator temperature Broken valves on reciprocating compressors Improperly seated scrolls Improper tonnage ratings across components Oversized coils 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, we ONCE AGAIN talk about superheat and subcooling. This episode is a recap to help people who struggle with the concept. You get superheat when you have 100% vapor, and you have subcooling when you have 100% liquid; any liquid-vapor mixtures are in a saturated state. We usually measure superheat outside at the suction or vapor line. It's best to take the superheat reading as close to the port as possible. Anything in the saturated state is boiling; you can only get the mixture at the boiling point of a refrigerant. Anything above the boiling point is all vapor, and it's superheated. Very high superheat indicates that the refrigerant boiled off very early in the evaporator, meaning that the system could be low on charge. On fixed-orifice systems, you charge a system via superheat. Zero superheat indicates that you have liquid in the suction line. When you have liquid in the suction line, you can cause compressor slugging, which leads to failure. You will usually only measure subcooling at the liquid line, usually right at the outlet of the condenser. When you read a higher level of subcooling, that means the system has more liquid stacked in the condenser. Any refrigerant below the condensing temperature is subcooled. In many heavy commercial/refrigeration equipment, you will have a sight glass instead of taking subcooling readings. Excess subcooling indicates that too much refrigerant has stacked up in the condenser, so you will likely also see an undesirable rise in head pressure. Bryan and Kaleb also discuss: Superman and submarine analogies Problems with the pot of water boiling analogy What really is steam? Sensible vs. latent heat Metering devices Superheat and subcooling targets vs. measured superheat/subcooling Adjusting charge Condenser as a desuperheating component Evaporative effect on the condenser 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 psychrometric basics podcast, Bryan and Kaleb talk about the properties of air. They also discuss dry-bulb, wet-bulb, dew point, and relative humidity. Psychrometrics is the study of the relationship between air and its properties. The psychrometric chart can be a bit intimidating, but you can use it in a variety of ways. A technician should care about this chart because it helps with whole-home diagnosis. You can't see the whole picture of someone's comfort unless you know the properties of the air. The left side of the chart is centered on wet-bulb and enthalpy, and the right side is centered on the absolute moisture content; the chart provides a comprehensive comfort profile if you use it correctly. Dry-bulb temperature is the basic sensible temperature of the air and gives you a one-dimensional heat measurement. Wet-bulb temperature directly relates to the evaporative properties of water in the air; the wet-bulb temperature changes based on the moisture content even if the sensible heat stays the same. So, wet-bulb temperature gives us a better picture of the enthalpy, which is the total heat content (latent AND sensible). The wet-bulb temperature will usually be lower than the dry-bulb temperature, and the difference is called wet-bulb depression. The only time when wet-bulb and dry-bulb temperatures will be the same is at 100% relative humidity, also called the dew point. At the dew point, the air can no longer hold any more moisture, so any additional water vapor in the air has no choice but to condense. Bryan and Kaleb also discuss: Radiant gains and dry-bulb measurements "Cold air is dry air" Relative vs. absolute humidity What really is temperature? Sling psychrometers vs. digital probes Load calculations Supply air and relative humidity Insulation and humidity 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.

Many contractors make a huge pricing mistake: confusing markup with margin. The distinction between those two things can be the difference between being profitable and losing it all. If you want to mark up something that costs $10 by 50%, you multiply it by 1.5 to get $15. So, did we make a 50% gross margin? No; we only made $5 on a $10 transaction; if we take 10/15, we get o.66. So, we really only made a 33% gross margin. When we factor overhead in, 33% is normally nowhere near enough. Not everything in the business will make money, and those costs become overhead costs. Businesses need to buy vehicles, pay for utilities, and save for emergencies, so you need a net profit from your sales to get enough money to pay or save money for those things. A good business makes 10+% net profit. If you don't do the math properly, you probably won't make that amount of money. If you use a 40% markup in cases where you have 30% overhead, you won't make enough money. If we have $70,000 in revenue and multiply it by 1.3, you won't get $100,000. Instead, you take the cost of goods sold and divide the number you're charging for by the cost of goods sold. 70,000/0.7 will get you $100,000, which accounts for what you need to earn to break even with 30% overhead. So, for a 10% profit, you'd divide 70,000 by 0.6 (30% overhead and 10% profit). So, using markup to set prices is a huge pricing mistake. The margins are where you really need to look. ("Margin" also sounds a bit better than "markup.") 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, Ron Saunders from Fresh-Aire UV comes on and answers questions about UVC. He clears up misconceptions and pulls no punches. Fresh-Aire UV (Triatomic Environmental) used to manufacture and sell ozone solutions, but the business evolved to sell UV and carbon-based IAQ solutions. UV lights exist on a spectrum of varying wavelengths. Some UV lights at the higher end of the spectrum produce ozone, but UVC light does not. UVC's frequency (~250 nanometers) is outside the range of light that produces ozone (shorter than 185 nanometers). Like any other IAQ product, UVC lights have advantages and disadvantages. To kill microorganisms, you need a mix of time, intensity, and proximity to the light. Since UVC effectiveness is so multifactorial, studies can be a bit misleading and can make the products look more effective than they really are by letting time and proximity make up for some slack in intensity. Visual light also doesn't necessarily reflect the light's intensity; you must be diligent about replacing them according to manufacturers' specs. UVC lights can kill all microbes, including viruses like COVID-19. However, light intensity and air velocity are both factors that determine how effectively UVC lights can kill viruses. Viruses don't propagate on coils like mold, though, so you don't have to worry about viral "growth" on coils in the same way you'd deal with fungi or bacteria. Ron and Bryan also discuss: Benefits and drawbacks of ozone solutions and oxidizers Time vs. intensity "Airstream kill rate" Viruses vs. fungi and bacteria How to answer customer questions about COVID-19 UV lights and component damage Handheld UV applications Hydroxyl radicals vs. ozone Scarce independent testing in PCO technologies UV light and skin/eye disorders Best COVID-19 product Using UV lights in ducts Measuring and detecting chemicals Stray light and VOCs 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 free-flowing conversation, the Trethewey family talks about growing up with This Old House, what the show is like behind the scenes, what Rich misses about the past, what the future holds for the trade, and some nerdy specifics between Bryan and Ross. The show business is a collaborative effort between the producers and talent (even though they're real people, not actors), and the Trethewey boys find the end result almost cathartic. This Old House was never scripted; there were beats and predictions about the content, but the content is all authentic. As the trade moves forward, Richard worries about weakening connections and producing leaks in the race to improve technology. He's glad that we work with far fewer deadly chemicals and materials nowadays, though. Many technicians are artisans at heart, and the future is bright because of techs who make ethical choices and do good, aesthetically pleasing work. (However, we can expect controls and ventilation to become increasingly important in coming years.) Bryan and Ross also brainstorm some innovative solutions for residential applications by looking at commercial equipment. Bryan enjoys thinking about using R-290 chillers and buffer tanks for residential applications. Ross anticipates a future focus on CO2 as a residential refrigerant; he thinks the future "magic box" solution is a CO2 split system for heating and cooling. Richard, Ross, Evan, and Bryan also discuss: Exposure to media Propane refrigerant Heat pumps vs. natural gas Hydronics Staying organized Pit corrosion on copper pipes What it means to be an "expert" at something and how it feels Core traits of successful skilled tradespeople Passive makeup air solutions New control strategies Getting new people into the trades Thanks to Richard, Ross & Evan for making this happen. Check out the This Old House podcast "ClearStory" on your favorite podcast player. You can also learn more about the Trethewey boys' work at TE2 Engineering and RST Thermal. 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. TE2 Engineering RST Thermal

Two of the great air and infiltration expert minds of our time, Gary Nelson and Steve Rogers from TEC (The Energy Conservatory), come on the podcast to talk about blower doors. They also discuss blower door testing and how it compares to real-life infiltration. A blower door has a fan to measure the air flowing through it, and you generally install it in a doorframe. Blower doors hook up to manometers to measure the pressure differential between the inside of a building and the outside. Generally, you need to adjust the fan speed to bring the pressure differential down 50 Pascals. Then, you measure the airflow through the blower. That is how you determine how leaky a building is; all the leakage comes out through the blower door due to the pressure differential. We use blower door data and mathematical models to estimate the natural infiltration rate. ACH50 is a means of expressing the leakage (air changes per hour at 50 Pascals). You take the CFM50 and multiply that by 60 to get the cubic feet per hour. Then, you divide that product by the cubic feet of the building to get your ACH50. You can apply a similar process to the surface area of a building instead of volume (though that's more common in commercial buildings). During natural infiltration, the leaks can move inside or outside the envelope, so it's difficult to use the blower door test to measure infiltration accurately. Wind and extreme temperatures also affect natural infiltration, and testing can't account for those. Gary, Steve, and Bryan also discuss: Testing pressure variations Analogies for measuring infiltration at 50 Pascals PSIG vs. PSIA Stack effect CO2 and infiltration Predicting infiltration rates with models Infiltration in cold climates How infiltration affects the latent load Duct leakage and building pressure Transfer grilles Balancing with precision manometers Check out The Energy Conservatory at energyconservatory.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 how to keep your humanity and make moral decisions when selling IAQ products. As the COVID-19 pandemic has started to grab hold of the world, we've seen an uptick in IAQ interest. When you have greater consumer interest, there are opportunities to hoodwink customers. While some IAQ products are indeed not very effective against viruses, there are some good products that you can sell to customers to benefit their health. Pretty much every product has an appropriate application, but sales and marketing can lead to inappropriate, ineffective usage. Some techs sell IAQ products for inappropriate applications just to make a buck, but many others simply don't know any better. For example, UV and PCO technologies can work very well for certain applications, but they are not the fix-all that some people market them as. When selling IAQ products honestly, you'll want to understand the efficacy data in the exact application you're selling it for. If you don't have the data for the application, don't make claims about efficacy. When it comes to oxidizers, you must also be transparent about safety concerns. Sure, you can explain how particles combine, but you also have to explain safety issues with the particles' behavior. Independent testing is also important. Paid studies can be manipulated to make a product look favorable. Ask if the product does what it's supposed to do. Then, you have to ask if the product is safe. Cold plasma and oxidizing products are a bit less effective than other PCO technologies, but they are a bit safer. The goal is to educate yourselves and the customer so that you can both make the best decision for the customer's health. 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.

Nikki Krueger joins us to talk about how humidity impacts indoor health and some ways to make our indoor air quality better (for real). Indoor air quality is all about manipulating the air in our homes to reduce pollutants and keep our air quality high. From air dilution to running bath fans to air purifiers, there is a lot more we can do to make our homes healthier. We can't entirely isolate ourselves from viruses, bacteria, and fungi. However, there are many other things inside our homes that can suppress our immune systems, and we can address some of those things with IAQ. To incorporate humidity control into our plans, we must look at the dew point. Dew point will change across the country and throughout the seasons, so we must work with varying conditions to keep RH in the 30-60% range. You can run kitchen and bathroom exhaust fans to manage moisture and VOCs. However, we also have to make sure the air we draw in is high-quality and won't upset people's allergies. So, ventilating dehumidifiers are an attractive option to replace exhausted air with high-quality fresh air. Temperature is mostly about comfort instead of health, but filtration, ventilation, and humidity directly impact the healthiness of our indoor environments. When we can control those three things, we can create indoor environments that are truly healthy. Ultra-Aire dehumidifiers can tackle all three of those, but education and holistic thinking are the real solutions to healthier homes. Nikki and Bryan also discuss: Air dilution Long-term payoffs The tricky IAQ puzzle in multi-family buildings Building design and IAQ Talking to customers about ALL options The "dehumidifier graveyard" What makes Santa Fe Ultra-Aire unique 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, Sal Hamidi of ProductsByPros joins Bryan to discuss what manometers are and how they measure pressure. Manometers measure pressure at a much higher scale than a micron gauge but lower than that of a pressure gauge; they measure pressure differentials by comparing static pressure to another source of pressure as a reference. Across all segments of the industry, we use manometers to measure static pressure. Static pressure is the pressure of air against the duct, not the actual air velocity. (Static pressure can give you an idea of the airflow, but you need pitot tubes or flow hoods to measure the actual airflow.) We can also use Magnehelics to measure static pressure, but it's just a specialized type of manometer. We can also use manometers in conjunction with blower doors to perform zonal pressure diagnostic tests. Blower door tests require the technician to pull the house pressure down to -50 Pascals. Then, the technician uses a very precise manometer to help determine the air changes per hour (ACH). Manometers are also invaluable tools in markets with lots of gas furnaces, as they measure gas pressure. You measure gas pressure on the inlet AND outlet side of the gas valve to make sure the pressures are correct. Every tech should have a regular manometer for everyday use to measure static or gas pressure. Techs on the building science side of the industry should have a precision manometer, which is an expensive but very precise instrument. Sal and Bryan also discuss: Pressure scales (in wc., PSI, Pascals, etc.) Absolute vs. relative scales Accuracy, precision, and resolution 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.

Michael Housh and Jim Bergmann join Bryan to look into the crystal ball to see the future of air conditioning and design the PERFECT residential system. Self-contained propane heat recovery chillers are futuristic devices that do simultaneous heating and cooling. While they may not be suitable for all climates, they can switch between heating and cooling modes, like heat pumps. They may also be able to service domestic hot water centrally as well. Although propane heat recovery chillers are impractical for residential use right now, they could hold the key to the future of air conditioning. Geothermal systems sound like a great energy source in theory, but the cost of installation may not be worth the investment for many homeowners. You only get payback on geothermal when it's time to replace the unit, so it takes a long time to recoup your initial expenses. While these systems may work well in northern climates, you won't see many geothermal systems in the South. Even though some customers have personal convictions about saving energy and efficiency, cost, effectiveness, and maintenance are going to be the most important factors to most homeowners. One of the challenges to adopting new technology is the lack of knowledge of new technologies. We expect a lot out of technicians when it comes to knowing how components work and what they do. When we introduce technology-heavy new systems, it can take a long time for technicians to become proficient with those technologies. Michael, Jim, and Bryan also discuss: Pool heating Equipment ROI Solving the flammability problem of R-290 Radiant heating and cooling Heat exchangers and piping resistance Pre-conditioning outdoor air Niches in the industry Ice banks New flammable refrigerants 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.

Thomas Talhelm, the founder of Smart Air, joins Bryan on the podcast to talk about how a filter and a fan in China sparked an IAQ revolution. The simple device changed his thinking about air purification. As a graduate student in China, Thomas witnessed the Beijing "Air-pocalypse" firsthand. That was when he became aware of the issue of air pollution and the potential health issues it can cause. So, he dove into the world of air purification. The most popular air purifier on the market was about $1,000, but Thomas felt that the price tag was way too high for protecting human health. Instead, Thomas decided to make his own air purifier with just a filter and a fan. He bought a laser particle counter to test his DIY air purifier and began publishing his data to make his health and safety data accessible and make cleaner air available to everyone. So, the goal of Smart Air is to lead an IAQ revolution by educating others about air pollution, sharing data about IAQ products, and improving health. The goal is NOT to earn lots of money. Thomas also uses his own experiments and data to answer tough but practical questions. For example, he has done studies to discover if indoor or outdoor air is cleaner. (Of course, the answer depends on location, but it's still a question that we've needed to ask for the sake of consumer health.) However, educating consumers and being transparent about the data requires a delicate balance of marketing and communication. Thomas and Bryan also discuss: Social enterprises vs. non-governmental organizations (NGOs) Smart Air in international markets COVID-19 and masks Being a researcher/professor Organizing data Sharing data in workshops The future for Smart Air Check out Smart Air at smartairfilters.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 talks about the steady-state voltage problem that can take out inverter boards and what to do about it. Inverter-driven equipment refers to a variable-frequency drive with ECM compressors and fans. We're talking about modern split-phase equipment rated for 208v or 230v power. However, the split-phase power will yield 240v. Most motors and components for 240v equipment have ratings for 230v AC power. L1 and L2 power can also be significantly higher than 240v, sometimes going as high as 250v. Inverter boards have a widespread failing problem in locations with high steady-state voltage. Surge protectors only work for spikes in voltage, such as lightning strikes; they don't protect equipment from steady-state high voltage. Inverter boards are rated for 10% voltage over 230v and 5% lower than 208v. The operating range is 197-253v, but consistent overvoltage that doesn't quite reach 253v can still lead to failure. We attempted to fix the problem by using the ICM493. These protectors have single-phase monitoring and have a NEMA 3R rating (suitable for outdoor usage). You can set the high and low voltage limits and get the benefits of thermally protected MOV surge protection. Although the inverters stopped failing, they started shutting off when they weren't supposed to. We discovered that the power companies were allowed to run up to 252v, which was right on the limit! Power companies may also run voltages 1-2v higher than 252v, so that explained the failures and shutoffs. If you decide to use the ICM493, you need to calibrate the voltage based on measured voltage (such as from a voltmeter). Then, you set it for 230v +/-10%. If you experience recurring problems with overvoltage, the power company probably won't be much help. In that case, you can use a buck-boost transformer. 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 and Michael Housh join Bryan to talk about testing A/C vitals. They discuss the new vitals mode in MeasureQuick and how it works. As with many of MeasureQuick's other functions, vitals mode is an invaluable tool for green and experienced HVAC techs alike. The new vitals mode helps us with charging, airflow, and other staples of A/C testing and commissioning. Vitals mode allows the user to give MeasureQuick some information about the system; when they provide that information, MeasureQuick can instruct them to use the most appropriate charging method. When you add enough refrigerant to create a liquid seal, you will begin to see a temperature drop across the evaporator. At that point, MeasureQuick would inform the user to stop charging and raise the airflow. MeasureQuick's vitals mode guides the user through the commissioning process by focusing on the main drivers: airflow and charging. The app also focuses on secondary drivers, including low-pressure, high-pressure, superheat, and approach. You can get to vitals mode by hitting the "trending" button twice. At the bottom, you can start with the quick charge; you then choose your refrigerant and the charging method. Vitals mode can help several new techs during the cooling season. The weigh-in feature helps prevent overcharging, which is a problem that's all too common. MeasureQuick has been working to fill the gaps in training by helping technicians do jobs correctly and avoid the confusion of listening to many different senior techs or trainers. Jim, Michael, and Bryan also discuss: Subcooling and line length Approach Sensible capacity vs. latent capacity Target temperature split Superheat Trade school vs. field training for charging Increasing the quality of HVAC instruction 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 how to use liquid line temperature as a quick diagnostic indicator on split A/C systems. Liquid line temperature is one of the first things to check when you approach a system. Checking that temperature is also a great way to get into non-invasive testing. The temperature should be between 4 and 15 degrees warmer than the outdoor temperature (unless it is wet). If the liquid line is cooler than the environment, then there could be a restriction. If there is a restriction, you could have a clogged liquid line drier or a partially closed service valve. When you have a larger condenser coil in relation to your capacity, your liquid line will be closer to the ambient temperature; the refrigerant must be at a higher temperature than the outdoor air to give off heat. You should also not see a pressure drop across the liquid line. An important value is the condensing temperature over ambient (CTOA). On a normally operating piece of equipment, the condensing temperature will be 15-30 degrees above the outdoor temperature. The CTOA is a design feature that sets the differential between the saturation temperature and the ambient temperature. So, before the refrigerant subcools, it will be 15-30 degrees above the outdoor ambient temperature. Subcooling goes below the CTOA. If we have a 30-degree CTOA and subtract 10 degrees of subcooling, then our liquid line will be about 20 degrees above the ambient temperature. If you add up all the numbers and find that the liquid line is warm, then you likely have an airflow restriction (dirty condenser, etc.). You shouldn't see a temperature differential across the liquid line; if you see one, then you likely have a restriction in the liquid line or lines that are too long. 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, we discuss viruses, bacteria, and fungi. We also explain how they interact with HVAC equipment, their effects on indoor air quality, and how businesses can protect their customers and employees. Since we work with the public, we can minimize the risk of viral transmission by keeping our distance between others and avoid handshakes and other forms of contact. However, we also have to respect the feelings of the customers we're serving. Many people confuse viruses, bacteria, and fungi (mold). All particles are small and would typically pass right through a MERV-8 filter; you typically need MERV-11 or better to catch all three. While our equipment can harbor those particles, the equipment can't create them. While bacteria and fungi can propagate on their own, viruses need a host to propagate. Viruses can go airborne, but they only grow and propagate inside our bodies. So, we don't need to worry about minimizing growth on surfaces or inside HVAC equipment. We make it harder for bacteria, fungi, and viruses to survive by keeping the relative humidity between 30% and 55%. That is part of the reason why certain viruses become prominent seasonally, though our own immune systems are also a factor. Probiotic cleaners also exist to attack biofilm on surfaces. To achieve that goal, probiotic cleaners promote good bacterial growth to fight the bad growth we want to eliminate. We may expect probiotic technologies to improve even more in the future. However, those won't affect viruses strongly because viruses don't GROW in equipment. We also discuss: Virus transmission Masks and gloves Mobile air scrubbers HVAC technicians as essential workers Microns Legionella COVID-19 vs. influenza HEPA and activated-carbon filtration Photocatalytic oxidation (PCO), bi-polar ionization, and UV lighting Is oxidization effective? Good vs. bad bacteria and probiotic cleaning 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 science and how to balance practice and experience with the "why" behind what we do. He also explains how either one can cause an error if you aren't careful. Science is not just about reading nerdy theories in books; it's all about understanding why the processes in our world. In that sense, many of us field technicians are scientists. When we use problem-solving skills in the field, we try to understand what is going on and why our proposed solutions might fix the issue. We partake in experimentation all the time when we look for solutions, too; we formulate hypotheses about what will happen when we apply a fix, and we test our hypotheses by seeing what happens. However, there has also been a rise in pseudoscience, which uses observation to come to a conclusion WITHOUT the due diligence of experimentation. We see this quite often in brazing; some old-timer technicians use poor brazing practices but still manage to get leak-free joints. While those brazing practices may work on the low side of the system, you can't expect the results to be the same when brazing in a compressor. The methods may "work" in some cases, but they're not backed by scientific understanding, so they can't produce good results under higher-pressure conditions. Science is not perfect and can go wrong, though. When we don't understand the application and the "why" behind the work, we can't expect products and tools to work as they're meant to work. That's when errors pop up. To avoid those errors, investigate the "why" and test out your hypotheses. Bryan also discusses: Multiple ways to do things Thomas Edison vs. Nikola Tesla Poor brazing practices Not pulling a deep vacuum Ozone generators and deodorizers "Hack" work 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 discuss some of the new, possibly strange-sounding business processes we've decided to implement at Kalos in 2020. First of all, we are going to add terms and conditions that our customers must agree to. These terms and conditions include a "hold harmless" disclaimer regarding viruses, fungi, and bacteria. Florida forbids us from discussing mold, so a "hold harmless" disclaimer protects us from liability for something we aren't even allowed to discuss. We also have to reinforce automobile safety to protect ourselves and our employees. Small fender-benders can spiral into serious legal problems when we lack proper evidence, so we decided to use GPS technology and dashcams in company vehicles. That way, we can collect more data on incidents to see who is really at fault in an accident. We've also clarified safety practices in our employee handbook. New business processes also include changing how we pay people per diem. In our construction and refrigeration divisions, our employees eat and sleep out of town, so they need compensation. We've put new processes in place to reimburse employees for those expenses without taxing that money. We also set rules based on the time of year, zip code, and average food/lodging rates. Overall, most of our new business practices are going into place to make Kalos a safer workplace with more efficient administrative processes We also discuss: Warranties on certain products "Assumption of privacy" Company credit cards vs. gas cards Dispatch/service software IRS "proof of transactions" Nurse triage and dealing with injuries Worker's compensation rates OSHA training and SDS Document signage and subcontractor agreements SambaSafety Slack vs. ServiceTitan Keeping track of parts, inventory losses, and supply house plans "Kaizen" 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.

Ben with Infinitum Electric comes on to tell us more about his super-innovative, groundbreaking PCB (printed circuit board) motor technology that we saw at AHR 2020. The Infinitum motor is a relatively simple permanent magnet motor that can also work as a generator. Infinitum got its start with generators, and the groundbreaking new motor technology works quite similarly to generators. These motors can also work with variable frequency drive technology. In this groundbreaking motor, the traditional stator has all of the iron and copper taken out, and copper is etched into the circuit board. When you take the iron out of the equation, you eliminate core losses and get a much more efficient stator. Instead, electromagnetic waves travel through the air via flux transfer over the air gap, which rotates the motor. The machine has low inductance overall. Energy efficiency is the core of Infinitum's philosophy. The original idea for Infinitum's motor came from optimizing performance in specific applications; Infinitum increased the efficiency while keeping the motors small and quiet. After that, the motor outgrew its application and opened the doors to innovation. There is great promise for Infinitum motors in the aerospace industry because they are lightweight, quiet, and highly efficient. However, Infinitum is also interested in short-term applications, including fans, pumps, and compressors in the HVAC/R industry. Ben and Bryan also discuss: Generator vs. motor technology VFD system integration How to operate motors with low inductance Investors and why they choose to invest Development of major automotive and aerospace technology Serviceability of the motors Using printed circuit boards as stators Starting conversations with OEMs Check out more about Infinitum and its new motor technologies at infinitumelectric.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.

Rick from Certified Refrigerant Services joins us to talk about recovery and refrigerant management. He also explains what to look for and do to get the most from your program. A refrigerant management program offers recovery services, reclamation, and other options for processing refrigerants. Rick's company also buys and sells refrigerants. With his line of work, there are also plenty of opportunities to educate contractors. The goal is to reduce refrigerant mixing and keep high-quality refrigerant in circulation. Mixing refrigerants kills their value, though it is sometimes inevitable. On the contractor's side, you can take steps to prevent mixing by diligently using tags and weighing the charge each time. When we commit to careful recovery practices, we can keep high-quality, discontinued refrigerants available for people who have those systems. Contractors can also do injustice to their customers when they recover into dirty tanks, though it can be difficult to understand those tanks' histories. As contractors, we have a lot of difficult decisions to make, but we must always act ethically in terms of EPA guidelines and put the customers' needs first. It's a bad idea (and illegal) to give customers unprocessed recovered refrigerant charges. You can't possibly know if the system has bad refrigerant (such as from a system that burned out) or other issues, so you're probably not helping anyone by giving them unprocessed recovered refrigerant. Quality is the key to the refrigerant management industry, and contractors can both contribute to the cause and benefit from it. Rick and Bryan also discuss: Refrigerant A/C vs. commercial chiller systems and mixing Recycling R-22 EPA refrigerant disposal reports Service vs. recovery cylinders Being proud of being in the HVAC/R trades How much should we really fill our tanks? Life cycle of air conditioners Refrigerant pricing R-410A recovery Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Chris LaPietra, vice president and general manager of Honeywell Stationary Refrigerants, joins us to talk about some new releases from Honeywell. He also covers refrigerants in general. As our industry reduces its reliance on R-22 (and eventually R-410A), we have turned to more flammable solutions. There is a tradeoff in safety for the lower GWP, though. However, along with some slightly less flammable A2L refrigerants, Honeywell is releasing two new A1 refrigerants: R-466A and R-515B (N-15). These are non-toxic, don't catch fire, and have a lower environmental impact than R-410A and R-22. The Montreal Protocol was a groundbreaking initiative to phase out ozone-depleting substances to help slow down climate change. As a result, R-22 has undergone a phase-out. The Kigali Amendment is the next step, which addresses global warming potential and targets substances with high GWP for a phase-down. So, as R-410A will go in a similar direction to R-22, manufacturers have come on the scene; they are developing alternative refrigerants that address the global climate initiative. Instead of creating new HFCs, manufacturers are inventing new blends and HFOs to replace HFCs. Honeywell wants to avoid creating undue risk in the marketplace. So, they take feedback from their customers and make sure technicians feel comfortable working with their refrigerants. They also keep the best practices pretty similar to those of working with R-410A. Chris and Bryan also discuss: Residential HVAC vs. commercial refrigeration solutions The ZE product line ASHRAE terms and definitions How R-32 is made (and A2L refrigerant blends) Global warming potential (GWP) vs. ozone-depleting potential (ODP) How Honeywell develops new refrigerants Trading off efficiency for lower GWP E-cooling and the potential of the electronics market 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 comes on the live podcast to talk through some commonly repeated EPA myths. We also discuss how to get the most from your recovery machine and tanks. The EPA exists to interpret broad laws into specific standards, such as by translating climate initiatives into venting guidelines. One of the most common EPA myths is that you cannot charge a leaking system. If you can repair the leak and get the leak rate below the specified percentage, then you can recharge the system. Not every country allows this procedure. On the subject of refrigerant losses to leaks, making leaks is also NOT a valid excuse to vent refrigerant; the EPA tries to get us to minimize losses as much as possible. De minimis exemptions exist to allow for us to service a system properly, not to give us loopholes for venting. Overall, it's best to use probes to take your readings, not manifolds. R-22 is another controversial subject that gives rise to some EPA myths. R-22 is NOT illegal, but it is no longer being produced or imported. There are limitations based on the amount of charge as well, but recharging a system with R-22 is NOT a crime. When recovering with a recovery machine, you want to prevent junk from getting inside of it (such as from the recovery tank). To protect your recovery machine, it's good practice to run the refrigerant through a filter-drier when returning it to a system, though that won't fully clean the refrigerant. Eric and Bryan also discuss: The ins and outs of new R-22 guidelines Pulling down into a vacuum Low-loss fittings and refrigerant trapped in hoses Whose responsibility is it to keep records? Drop-in refrigerants, mixing refrigerants, and topping off Recovery tank safety basics and cleanliness How recovery machines work Recovering in the liquid phase Heat transfer in recovery PPE 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.

Gurminder Sidhu joins us from NATE to talk about what NATE is all about and bring us some news about the new changes and improvements. NATE was created for the industry by the industry; the organization arose from a need to promote education and standardize HVAC qualifications. Today, NATE continues to address the industry's needs by offering education and certification for technicians. NATE also understands the need of explaining the "why" behind our daily work. The people at NATE also believe in continuing education and offer learning materials to techs of all levels, as well as study guides for their exams. People from all sectors of the industry contribute to the study guide content. These people also review it to ensure that everything in the guide is relevant and accurate. The study guides take what technicians have learned in the field and put them into a form that helps them prepare for quizzes. These guides also have practice questions, a glossary, and formulas. Technicians must take a core and specialty exam before the big NATE exam. When it is time for you or one of your employees to take the NATE exam, you can arrange a date and time to take the test at a local testing organization. NATE is currently working on an alternate pathway to certification for those who are new to the industry. This pathway has a series of five smaller exams that people can take in any order. You can take the alternative tests either traditionally or remotely with an online proctor. Gurminder and Bryan also discuss: Four levels of NATE certification The study guide creation process How employers benefit from employing a NATE-certified technician New NATE user interface Get started or keep up with news from NATE at natex.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.

Alex Meaney from MiTek/Wrightsoft joins us at AHR 2020 to talk about some HVAC design myths and how to bust them in your mind. It was a really fun talk with a great guy. One common HVAC design myth worth busting is that we can use a set friction rate with a Ductulator to make duct systems work. The friction rate only applies per 100 feet, and it has different degrees of impact based on duct sizing and fan speeds. We CANNOT guarantee that a system will work if we subtract losses to filters, coils, and grilles until we reach a set friction rate (usually 0.1 or 0.8). We experience most of our pressure losses at the fittings, which the friction rate doesn't account for. To prevent some of these myths, we can move away from manual math and start using more software. However, we have to know what our numbers exactly are and what the performance conditions are. For example, filters can show a static pressure drop rating of 0.1, but that WILL change depending on the CFM. Velocity is a confusing area for techs because we have face velocity and duct velocity. Face velocity refers to the speed of air at the register whereas duct velocity refers to the air speed within the duct. These can get a bit complicated when you throw dampers in, but duct velocity doesn't have that much of an impact on the face velocity; the register has a much greater effect on face velocity than a damper in the middle of a duct. Alex and Bryan also discuss: Starting off by learning the wrong thing 12,000 BTUs per ton Radial duct systems What really is "static pressure?" Oversizing ductwork Creating vs. relieving friction Manual D Ideal velocity Variable-speed technology Efficiency vs. moisture removal Sensible heat ratio (SHR) and Manual S Latent loads 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 joins us again from AHR 2020. This time, he discusses what mentors and role models do in our trade and why they're important. Mentors are not just the grouchy senior techs who throw hammers at apprentices. Mentors have an active role in others' professional development; they spend a lot of time with their mentees and actively aid their growth. Not everyone is cut out to be a mentor, as the role comes with a lot of responsibility (and possibly stress). Role models indirectly influence others by doing good work and inspiring others to do the highest quality work; we should all strive to be role models. However, the mentees need to put in a lot of work and must have emotional intelligence. Both mentor and mentee need to ask questions about the work and each other. The relationship is all about involvement and intentionality. Mentors also have to care about their mentees as people, not just as students or technicians. They respect their mentees' values and acknowledge where their own shortcomings are when communicating with their mentees. However, mentors also know when to question and challenge their mentees when necessary. Mentees are entitled to clarity, and a good mentor understands that there has to be mutual understanding and trust in the relationship. Relationships take time, and mentors usually need to give their mentees a chance to prove their work ethic before they commit to the mentorship. As a mentor, you must understand that your mentee doesn't have your perspective, and that's where empathy and expectation management are required. Andrew and Bryan also discuss: Individual learning styles Formalization of mentorship Investment in training vs. mentorship "Multimedia" and internet mentorship Dave Barefoot stories How to start a mentor-mentee relationship Filtering through unsuitable mentees Setting expectations before goals 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, HVAC School team members Kaleb and Leilani walk the floor and talk to various people about their products and companies at AHR 2020. Bryan also has a quick conversation with Frank from HVAC Outlawz. The newest RectorSeal surge protection (RSH-50 with the 60A disconnect) uses MOVs and gas discharge tubes, which work together to fight off power surges. The effectiveness of the product has allowed RectorSeal to give customers a lifetime warranty on their product. RectorSeal also has a new drain cleaner, Nu Line. Nu Line eliminates the biofilm in drains AND protects the drain from growth after cleaning. One of Bryan's AHR 2020 highlights was speaking with Frank of HVAC Outlawz. Frank wants to push the limits of what we know so that we can perform the best work possible. In his 15 years, he has worked with a wide range of equipment. His experience led him to start creating content on Facebook and Instagram (also with inspiration from Andrew Greaves). He also involves himself in local trades education, which is the key to making our trade accessible to young people. Emerson is also an HVAC titan that participates in events like AHR 2020. Emerson is at the forefront of new HVAC technology and always focuses on doing the right thing for contractors, wholesalers, and industry partners. We also explore: Gas discharge tube technology Various applications for Line Sets Inc. products Measuring duct pressures and velocities with Dwyer Refrigeration Technologies Venom Packs Maintaining building envelope integrity with Friedrich A/C Recovery units with NAVAC Emerson's Sensi Predict and Multiple Thermostat Manager Fieldpiece vacuum pumps and Job Link probes Ultra-Aire dehumidifiers RGF Environmental Group REME Halo LED Women in HVACR Ultravation Synergy 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 recording from the AHR Expo, Kaleb Saleeby, Nate Adams, Michael Housh, and Steve Rogers discuss building performance. The building science world is an exciting place; we're all excited about improvements to reheat dehumidification, which is when we use waste heat to take care of humidity without cooling. As equipment becomes more efficient, we also look forward to tackling new challenges that make us think more broadly. New people are also stepping up, using new tools, accessing more knowledge, and doing better work. Building performance is becoming more important in HVAC via HVAC 2.0, which focuses on design efficiency. However, the biggest challenge right now is making HVAC 2.0 sustainable and profitable. We must simplify and scale building performance; when we make it accessible, we can work it into the HVAC industry and do more thorough work. One of the challenges to widespread adoption is the lack of experience with building performance. The average technician simply doesn't have the needed exposure to building science concepts and practices. Perhaps the best way to bring people into the building science side of the business is to work on the techs' own homes. We need to bring the personal part of building performance to the technicians and their families if we want to see widespread adoption of HVAC 2.0. We also need to make building performance solutions accessible to the consumers. Although the solutions may be too expensive for many customers right now, the goal is to start holistic comfort conversations. Kaleb, Nate, Michael, Steve, and Bryan also discuss: Tapping into the engineering mindset Economic sustainability Psychrometric charts vs. app-based learning Math vs. software Working with techs and the CSRs The Gulf of Disappointment Contractor relationships Economic and environmental impacts Fossil fuels Upgrading the electrical grid Propane 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 from Refrigeration Technologies talks to us about his journey in business, some new and old products, and how well the business is growing. Refrigeration Technologies tries to make products that do the job correctly the first time and are safe for techs to use. The products are odorless, don't burn skin, and are safe around food. John and Mike Pastorello are passionate about using chemistry to make quality products that make techs' lives easier. Mike joined his father's business full-time when he was 23; he performed a lot of the menial tasks while his father developed the products. Nylog is perhaps one of the most popular yet controversial products. The product is made of refrigeration oil, which is inside the system anyway. While many people may be suspicious of additives to avoid warranty complications, nothing inside Nylog will harm the system. It also won't clog the lines when used properly. Lately, Mike and John have made highly concentrated cleaners that have taken all the excess water out of coil cleaners. These Venom Packs are pure concentrate, meaning that they are very strong but maintain their original cleaners' non-toxic properties. They are also easier to store and come in brightener, all-purpose, evaporator, and condenser varieties. Refrigeration Technologies cleaners also work on tough bacterial zoogloea, a common plague in humid climates like Florida. The Pan & Drain Treatment also works very well to clean out and treat drains. The spray is also tough on odors. Refrigeration Technologies has experienced a lot of growth recently. Most of the company growth happens in John's lab, as the products are constantly getting better. The goal is to improve the quality without raising prices, and improvements to packaging are crucial to that element of growth. The company is also very active on social media and actively takes feedback. 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.

Richard Trethewey from This Old House joins Bryan on the podcast and tells his incredible story and shares some encouragement and laughs. Richard works with his sons, Ross and Evan. He has always worked in a family business and then left it to start his own with his sons. Family businesses truly are the backbone of this industry, as our business attracts lots of family-oriented business owners. Richard's sons volunteered to join the business early on. This Old House started off with a phone call from PBS about a home-renovation show idea; Richard had to start the show from scratch with no money, but his father agreed to do the show. The first years of the show were difficult because that was before Home Depot and the internet became popular, so DIY home renovation was still pretty new and unknown; Richard worried about "selling the secrets" of the trade. However, his main concern was with doing good work and setting a positive example for others whenever they watched him. If Richard had to give one piece of advice to young people, it would be to join the skilled trades. Many high-profile jobs have an ebb and flow of good workers, but the skilled trades ALWAYS need good workers. Regardless of where people are or what the market looks like, people will need comfort. One of the most rewarding things about being in the skilled trades is being able to inspire others to obtain the skills to provide for themselves. Nowadays, Richard spends time learning about new technologies and feels excited by the prospect of making American technology even better. He looks to Western European HVAC technologies as an example of what we can do. Richard also looks forward to empowering and inspiring the new generation and getting them to a point where they have pride in their work. Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

This podcast is by Sal at Products by Pros, featuring Bryan Orr of HVAC School. In this episode, Sal asks Bryan all about micron gauges. Products by Pros Guest: Bryan Orr What should technicians look at when deciding on a micron gauge? You should look for superior accuracy and resolution, especially if you'll be doing decay testing. You need to see what the trends are in clear detail. (The Bluvac app makes that easy.) Why should a tech even use a micron gauge? You use a micron gauge to verify that you have pulled a proper vacuum. What role does fear or pain play in the use of micron gauges? People respond primarily to pain; most technicians in the field know what they can get away with to avoid the pain of punishment for bad practices. What type of technician doesn't care about proper vacuum or micron gauges? They typically come from companies that don't care about having clear startup and commissioning practices. What is the cost of adoption for high-end tools? Technicians think in terms of the tyranny of the urgent. They have to take time to learn it, and many of them don't have that time. What are the pressures techs deal with? Scheduling pressures are already immense, and field techs are also under constant pressure to get work done and do their jobs even better. How can techs save time and relieve pressures? Learn how to do things right and become proficient with newer, better tools. How do you pull a proper vacuum? Don't use leaky manifold gauges during evacuation; just use good-quality vacuum-rated hoses. Use core remover tools and keep your micron gauge as far away from your pump as you can get it during evacuation. What are the incentives for techs to do things properly? A common thread among many techs is that they want to avoid blame; if we focus on reducing blame, then techs might feel more encouraged to learn and do things correctly. (There will always be sticks in the mud, though.) What role does integrity play when it comes to business owners doing things properly? Integrity comes in when we show techs how to do procedures right. When you teach techs how to do things right, the work will speak for itself, and your company will earn a positive reputation. What micron gauge from AccuTools would you suggest for technicians? I recommend the Pro for new techs or installers, the LTE for intermediate technicians, and the Micro for pros. Why do you consider AccuTools micron gauges reliable? I consider those products reliable because they work consistently with the typical wear-and-tear that's expected in the field. Except in cases of extreme abuse, they seem to maintain their sensing abilities very well. Looking to learn more? Go check out hvacrschool.com/evac or the AccuTools YouTube channel HERE. Want to have your local suppliers carry AccuTools? Reach out to [email protected] If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Rachel and Eric Kaiser join us to talk about connecting STEM concepts to the trades. They also explain how to teach STEM in a way that sticks. STEM refers to science, technology, engineering, and math. In traditional classroom settings, teachers usually tout these subjects as the ones that lead to the most promising careers. However, STEM concepts are not limited to their respective subjects; we use many of those scientific and mathematic concepts in the trades as well. Rachel believes that undergraduate programs would be more effective if they focused more on teaching critical thinking and less on making students meet requirements for degrees. Eric believes that traditional education needs to be more holistic; right now, trades education fixates on details; that approach may help for teaching specific tasks, but it doesn't broaden the students' knowledge. We can start talking about STEM more broadly when we start eliminating stigmas around STEM topics. For example, many students dislike math, but many of those people still use math effectively in several real-world applications without knowing it. We can break down that stigma against math to start having productive discussions and connecting STEM to the trades and other careers. The next step is to spark interest in others so that they seek out new STEM knowledge. The HVAC trade has many scientific concepts in play, even though we focus on diagnostics and field techniques at work. Most of our diagnostic skills are informed by the principles of heat transfer and phase changes. Rachel, Eric, and Bryan also discuss: HVACR Training Symposium Undergraduate vs. graduate programs University research and funding Principles of algebra in real life Gas laws and galvanic corrosion as chemistry concepts in HVAC Theoretical vs. diagnostic vs. instructional applications Continued learning vs. degree programs Applications and limitations Hands-on BEFORE theoretical Choosing to learn Improving safety and productivity through education Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

This short episode is a review of a list of installation reminders made by Kalos manager Jeff Crable. Kalos is doing a bunch of these installs for a commercial customer. Hopefully, the business leaders can take a few things from our checklist and help out their installers. Whenever we do an install for our large commercial customers, we give our installers a long checklist of reminders; that way, they can do the best install possible. Some of those install reminders include: Don't rush the details. Ensure the drain line is clean, pitched correctly, trapped, ventilated, and insulated. Install float switches in the unit and auxiliary pan. Wire in series and test. Replace the auxiliary drain pan or ensure that it's in good condition and has proper sizing. Hang the auxiliary drain pan WITH Unistrut; don't hang with wire. Install a new thermostat. Attach and hang the ductwork properly; silver-tape will NOT support duct board plenums. Replace incorrectly sized breakers (for licensed electrical contractors only). Replace old and faulty disconnects (for licensed electrical contractors only). Ensure that the outside conduit is watertight or replaced. Anchor condensers properly with isolators if the pad is attached to the building foundation. Mark the unit with the correct number using paint and stencils or vinyl stickers. Post pictures of the units and data tag in the appropriate location in our communication software; make detailed notes. Address vertical air handlers and take them as they come. If a unit is in a difficult area, try moving to a more accessible place if you can. Pour gallons of water into the drain pan and observe draining. Listen for noises of concern. All work will be checked by lead techs or managers. Get everything right the first time if you want a full bonus. 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 face-to-face discussion, Bryan and Kaleb share some tips for diagnosing and replacing the reversing valve on a heat pump. These valves may also be known as four-way valves. Kaleb and a trainee recently had to diagnose a heat pump with a scroll compressor. The motor was also over-amping due to a failed capacitor, and the compressor was making a metallic grinding noise. Because reversing valves are pilot-activated, they need a pressure differential to shift, so the scroll plate can sometimes pop up and make noise during bypass. Another possibility was that the compressor could have been running backward, but that wasn't the case. There are some cases when techs misdiagnose a compressor problem as a reversing valve failure; however, in Kaleb's case, there was a problem with the reversing valve that then caused compressor failure. To determine if a system has a reversing valve issue, you should look at the temperature difference across the valve (more than 3 degrees). Another thing to look for is an abnormally low compression ratio (high suction, low head pressure). You also want to watch the compressor amperage, as it will likely be lower than normal. When doing more advanced tests, such as delivered capacity tests, use Bluetooth tools to make your life a lot easier; that way, you can clamp your probes on. When Kaleb replaces a reversing valve, he cuts them out wherever possible. If he can't cut them out, he sweats them out and sweats the new one in. Sometimes, it's also easier to remove the entire condenser coil during replacement. Kaleb and Bryan also discuss: Common suction port Causes of compressor damage Unreasonably hot discharge lines Compressor amperage drop Common suction, common discharge lines Kaleb's compressor replacement Cutting out suction dryers Sweating out reversing valves in Trane units Purging with nitrogen before a pressure test Deburring properly 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 the times he has been hoodwinked in his career. It's time to name and shame. One time at a trade show, Bryan came across a product called KVAR. KVAR is already an electrical term for kilovolt-amps reactive; those are volt-amps that show up and generate heat but don't do anything useful, just like foam in a beer mug. So, the product supposedly balanced out the power factor to save energy. However, power companies don't charge based on VA; they charge based on wattage, which already accounts for the power factor. So, the KVAR products made no actual difference; the KVAR motor was simple and very inefficient, which did little to improve energy savings. Bryan was hoodwinked because he didn't ask the right questions. He should have asked about the difference between volt-amps and watts, and he should have asked to see hard data about energy savings. Hoodwinking happens quite often in our industry; the only way we can prevent it from happening to us is to learn more and ask the right questions. So, how do we avoid hoodwinking? The best thing we can do is ask to see the data. Don't accept platitudes, graphs, or name-dropping; ask about the test methodology and specific details. Indoor air quality (IAQ) is an area that has a high potential for hoodwinking. Unfortunately, the IAQ products' data is often incomplete and only tests for a few contaminants. While the products have the potential to do a lot of good, there is potential for deceptive marketing and lazy science. Something to remember, however, is that not everybody who hoodwinks you has bad intentions. They sometimes don't understand what they're doing or are more familiar with marketing than science. Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

This live podcast episode is all about pool heater talk. We cover gas pool heaters and pool heat pumps, explaining how they work and common issues. Pool heat pumps work a lot like air conditioners, but they have heat exchangers that help transfer their heat to the water. Instead of having a typical condenser, a pool heater has a unit that works like a heat pump's outdoor coil in heat mode. There is usually an option to cool the water, but there are almost no cases where someone would want to use that mode. The heat exchanger is the core component of a pool heater, and this part has evolved a lot to improve efficiency and reduce the effects of water chemistry. The old designs were cupronickel tube-in-tube heat exchangers where the refrigerant and water flow in opposite directions. Unfortunately, these corroded and failed easily. Titanium coaxial heat exchangers replaced those, though they can still fail. If heat exchangers fail, water can get into the refrigerant circuit; when that happens, the whole heat pump will fail prematurely. Actuators are also components that commonly cause issues. Gas pool heaters work similarly to gas furnaces, so they tend to work better than heat pumps in low-ambient conditions. However, they have their own set of challenges. They have very short lifespans in Florida and corrode easily because steel, heat, chlorine, and water all interact in the same area. Inducer fans especially tend to rust out easily. We also discuss: Manufacturer quality control Hooking up gauges Water level and flow Low ambient conditions BTUs Float switches Internal thermal overload Heat and water pressure losses Temperature sensor issues on pool heat pumps Pool vs. spa mode Special considerations for indoor pools Flame rollout Cleanliness issues Double-lugging Circuit breaker failure Piping configuration and valves 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.

Alejandro Rios from True Refrigeration comes on to talk about self-contained R290. He explains what it is, why to love it, and how to service the sealed system. R290 is pure propane, and it has recently made a name for itself as an emerging refrigerant. It is an A3 refrigerant, meaning that it is non-toxic and highly flammable. As we move away from HFCs and other refrigerants with high global warming potential (GWP), we will encounter more flammable refrigerants, usually A2L and A3 refrigerants. R290 is a natural refrigerant and has a GWP of only 3, making it more attractive than 400-series blends and some A2L refrigerants. You can also vent R290 because it has such a low GWP and an ozone-depleting potential (ODP) of 0. Self-contained systems that use R290 have a relatively small charge. However, they effectively run colder coils. Due to the colder coils, these systems have a net refrigeration effect (NRE) about 30% better than previous equipment models with other refrigerants. R290 is also versatile and can work in medium and low-temp refrigeration. Many of the service procedures are quite similar to other refrigeration systems. However, you have to be EXTRA diligent to check for flammable gas leaks; you must use a combustible gas meter for leak detection, NOT your typical electronic leak detector. Like most self-contained equipment, True's equipment is factory-sealed, and you must braze in your own service ports. However, as long as you vent the refrigerant in open areas and purge the line with nitrogen, you normally don't need to worry about anything catching fire. Alejandro and Bryan also discuss: Regulations for self-contained systems Terminal venting High-efficiency R410A systems Small charges Residual refrigerant and evacuation Adding service ports and sealing them Refrigerant recovery with SHORT hoses POE oil Energy savings Check out True'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 podcast episode, Bryan explains what happens when your low-voltage circuit puts out a lower voltage than it should. Bryan recently received an email asking about the low voltage on a 20-ton split system with a long control wire; the voltage coming back to the condenser is only 19 volts, so there was some contactor chattering. First, in a case like that, you'll want to figure out why the voltage isn't as high as it should be. The control wire and line sets could be longer than the design specs, which may contribute to the problem. If the distance between components is the main issue, then you can use a relay to mitigate voltage drop and amp draw. You'll also want to check that you've tapped the transformer correctly. Since most transformers are single-phase, they'll probably start off tapped to 240v; when you're dealing with three-phase equipment, you must ensure that the transformer is tapped to 208v. One of the obvious issues to check is the voltage drop. If 26 volts are coming out of the transformer but you're only measuring 19, then you're clearly losing volts and have some resistance. Think about ALL of the conductors; is the drop the same across all of them? If so, then you've likely got a length and wire sizing problem. You can correct that issue with proper wire sizing; you can't always control the length, but if you can, then it's a good issue to address. If there's an issue with only one conductor, then the switch could have a problem, or there might be some wire splices. If the load is drawing higher current than it should, then something could be impeding the motion on the solenoid, contactor, or another electrical component. 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 codes and common causes for failed inspections. We talk about these topics both broadly and with some specifics. Many of the places where we fail to meet codes are on the electrical side. Electrical components have fire and electrical shock hazards, and codes are stringent for arc and ground fault protection. Leaking current to ground can shock someone, and arcs can cause damage to property and human life. We commonly see failed inspections due to improper marking on the air handler. In the HVAC industry, we have specific wire and breaker-sizing codes for our trade (440 in the NEC). Inspection failures are common in this area, as it's easy to leave the incorrect breaker in place. You also must have a disconnect or easily accessible circuit breaker that can function as a disconnect. In our market, we must also insulate drains and show proper attention to strapping, pitch, float switches, and cleanouts; otherwise, the drains may fail inspection (though it's rare). Clearances also come up quite often and are especially relevant to safety in our industry, as we don't want condensers blocking panels. Obstructed rooms or lack of egress are also common code violations related to safety. Anchorage is another safety-related code category, and there are special requirements in locations that are prone to high winds (like Florida) or earthquakes (California). You can't assume that units installed on rooftops have been anchored correctly, so be sure to check the anchorage. We also discuss: Pulling permits CO detectors PVC primer on condensate drains National Electrical Code (NEC) vs. AHJ Catwalks in attics Duct sealing and mastic vs. metal tape Florida Energy Conservation, Mechanical, and Building Codes Customer complaints Furnace venting and GAMA tables Smoke detectors Locking caps Wire protection Sealing boots 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 from the Castbox app, we have four techs join us to talk about common furnace issues and best practices. Those of us in heat-pump-dominant markets rarely have to worry about common furnace issues related to gas pressure and flow. In that same vein, we also don't have to worry about clocking the gas meter, which is a common practice on gas furnaces. Checking input and performing combustion analysis is critical to the diagnostic process AND can give you an idea of the unit's safety. There is no reason NOT to do combustion analysis when commissioning a furnace. Furnaces also have electrical components with flashing error codes. You must be careful when interpreting those codes, as multiple issues could show up under one code. (Compare it to going out on high pressure; that error doesn't necessarily indicate a pressure switch issue and could entail other problems.) Common codes deal with the flame sensor, but flame sensor failure is rare; the issue could come down to simple maintenance. When cleaning parts, the most important thing to do is make sure the carbon and debris come off; you don't have to overthink the cleaning material. Cracked heat exchangers are common issues that can present unsafe conditions, though they won't always have CO problems. If there is an issue with a cracked heat exchanger, the technician usually CANNOT turn off the system at the gas. (We usually CAN shut off the power at the switch, though.) Only the gas company can typically shut off the gas. We also discuss: Restrictions at ports Adjustments for altitude Carbon monoxide poisoning Proper drain line Clocking the gas meter in commercial settings Gas pool heater problems Parts that commonly need cleaning Steel wool vs. sand cloth High limit codes Clogged burner wings CO-monitoring Venting issues and negative pressurization Intake/exhaust pipe issues Power passing vs. consuming Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

David Richardson with NCI, author of Duct Dynasty, joins us on the podcast to talk about mixed air temperature and more topics of interest. When you bring outside air into the home, you introduce positive pressure into the home. That way, you can offset air lost via mechanical ventilation or through cracks, improving air quality. We often assume that the building will "breathe," but tighter constructions make it difficult for the home to bring in enough fresh air to offset harmful chemicals and VOCs. We need to measure two different kinds of airflow: fan airflow and outside air. When we have these numbers, we must figure out how much air is coming through the outside air intake. The fan airflow represents 100% of the air content after mixing has taken place. You can perform a duct traverse to get the airflow measurement; when you plot the fan airflow, subtract the two to know how much return air you're getting BEFORE mixing with the outside air. Once you have your airflow measurements, you must break those into percentages. You must determine the percentage that matches up with the temperature you want to use for the mixed air. Subtract the outside air from the fan airflow to get the CFM from your baseline. You could get 95% of your airflow from the return and 5% from the outside. Once you know the outside air temperature and the percentage of outside air, you will know how much the outdoor temperature will affect the return air and space temperatures. David and Bryan also discuss: How David got into writing Blown-in cellulose insulation Designed and undesigned leakage Duct traverse tools and procedure Dry-bulb vs. wet-bulb measurement applications SEER vs. AFUE Duct leakage Learn more about NCI at nationalcomfortinstitute.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.