Many techs know just enough about economizers to bypass them. In this podcast episode, Jerry Eavenson and Bryan talk about the basics of what an HVAC economizer is and how it functions. Economizers typically work on the air side of package units and help pull fresh air into a structure. Economizers are almost exclusive to commercial HVAC. Climate also plays a role in their usage; you will not find many economizers in hot and humid places like Florida. An economizer is generally an energy-saving device that brings fresh air into a building if it is of a higher quality than the return air. These economizers determine if the outside air is better than the return air via enthalpy controls. Enthalpy controls evaluate the humidity and temperature of the air. When you set up an economizer, you can easily go wrong if you don't understand the sensors that are involved in the setup. Many economizers have dry-bulb or enthalpy sensors (wet-bulb), and these sensors are not interchangeable. You typically have to know the model number to differentiate the two types, but the model information is readily available on the internet. Typically, your differential set points will depend on your climate zone. You may come across fixed-enthalpy or differential controls. When it comes to economizers, acquiring documentation is the best move. As with all types of HVAC equipment, reading the manual is the key to understanding what an economizer does. Jerry recommends identifying the controls, sensors, and functions of the equipment. Economizers may vary greatly across models within a manufacturer (let alone across manufacturers). Jerry and Bryan also discuss: Heat loads of commercial spaces Variable frequency drives Sensors Economizer setup Honeywell Jade Cooling stages Controls Dehumidification-only application possibilities Return duct sizing Climate zones   If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Dan Holohan is the father of modern steam heat training. This episode is a narration of his in-depth steam article "A Steam Heating Primer" from HeatingHelp.com. Read that article HERE. Check out more about Dan's work at heatinghelp.com. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In today's podcast, Bryan talks with legendary Hydronics author and trainer Dan Holohan about the history of steam heating and some practical applications of old ideas. Recently, Dan has been working on more novels, having published two of them over the past few months. Steam heating is a "lost art" nowadays; it has become increasingly uncommon and has been disappearing since the Vietnam War. Many people who understood steam heating either retired or died after the Vietnam War. Many elements of steam heating are difficult to understand or surprising. (For example, steam pressure has a surprising relationship with velocity: low-pressure steam moves through piping much more quickly than high-pressure steam.) So, Dan Holohan is on a mission to revive that knowledge and teach the newer generations about the lost art. There are many older steam heating systems still operating today, especially in the older large buildings in New York. Dan learned a lot about steam heating when working on these old systems and optimizing them. Most of the time, he optimized those systems by removing unnecessary accessories, not adding components like steam traps. Many old boilers used coal as a heat source. Nowadays, many old boilers have been fitted with conversion oil burners with thermostats, but they are still piped for coal. Some systems now have multiple risers or massive vents on the main riser to prevent the thermostats from getting too hot too early and satisfying the thermostat too early. We call that master venting, reducing pressure and allowing steam to move very quickly and efficiently. Dan also discusses: The 2-PSI standard Transportation metaphors for BTUs in steam Harmful renovations for old boilers Replacement vs. restoration mindsets Gaps in steam boiler education Monopolizing the market if you HAVE the education Boiler piping and venting Two-pipe vs one-pipe steam   Find out more about Dan and hydronic heating at HeatingHelp.com. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

This special podcast episode focuses on the tragic life and times of Spark Ranger Roy Sullivan. Roy Sullivan was a park ranger who was born in Virginia in 1912. He grew up in the 1920s when the mining industry was in full swing and had scrapped up the beautiful mountain landscape. In 1935, Shenandoah National Park was founded, and Roy decided to become a park ranger. He wanted to help restore the land and protect it from human destruction, such as the mining industry. One of Roy's duties was to scope out the forest on the new fire lookout tower. That new tower had yet to have a lightning rod installed. One day, a lightning storm approached while Roy kept watch, and lightning struck the tower. Roy survived the strike, though he was badly burned in the incident. In July of 1969, Roy encountered lightning once again. That time, Roy was driving a car. Although many people believe that the tires are insulators, most people are protected from lightning by the Faraday Cage effect; the current travels through the metal around you until it reaches the ground. Roy, unfortunately, forgot to close his window and had a lightning charge from a nearby tree strike him through the window. Roy got struck with lightning yet again while doing yardwork a little while later after a transformer was struck by lightning. He was allegedly struck by lightning several times after that, including on a fishing trip where he ALSO had to outrun a bear after getting struck by lightning. However, even though Roy had the scars, these lightning strikes are unconfirmed. Sadly, Roy died by a[n allegedly] self-inflicted gunshot wound. However, the legacy of the Spark Ranger continues through his ongoing world record for "Most Times Struck By Lightning."   If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In today's podcast, Bryan and Jamie talk about the electronic expansion valve (EEV). Bryan and Jamie describe how EEVs work and the reason they exist. In the process, the hosts also review a wide range of metering devices. We made this podcast to address the rising demand for EEVs in the aftermarket element of the HVAC business. Like the TXV, the EEV is a metering device. Metering devices create a pressure drop as refrigerant moves from the liquid line to the evaporator. Traditional refrigerators typically use capillary tube metering devices because they require a constant temperature and operate in a fixed temperature environment. However, TXVs are a bit more variable but open linearly and are dictated by a minimum stable superheat value. EEVs are also variable, but they can influence the superheat more directly; the superheat always exceeds the minimum stable superheat. Therefore, EEVs can increase efficiency by reducing the evaporator temperature and compression ratio by increasing saturation temperature. Even though EEVs dominate the grocery refrigeration market because of their head pressure control, we can use them in residential HVAC too. The EEV controls superheat more precisely than a TXV, and their algorithms can maximize efficiency and fill the evaporator coil with the most refrigerant possible. There are two types of EEVs: the pulse-width EEV and the stepper motor EEV. The stepper motor has "steps" to modulate the degree to which it opens or closes. The pulse-width EEV either opens or closes, much like a solenoid valve. Bryan and Jamie also discuss: Hot pull down Ideal compression ratios and efficiency Minimum stable superheat Compressor cooling accessories Downsides of oversizing TXVs Evaporator superheat vs. suction superheat Technological advancements for EEVs, especially for Danfoss EEVs Less obvious advantages of EEVs over TXVs   If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In today's podcast episode, trade school student Chris Caldwell interviews Bryan about trends in the HVAC industry, his business, and the future. Chris works in the HVAC business as a service tech and attends trade school in Alabama. New trends include spending more money on testing instrumentation. Nowadays, there is a greater reliance on test instrumentation to produce accurate measurements. Diagnostics have certainly improved over time. On top of that, Bryan sees the industry's potential to improve other practices like evacuations. Customers have paid more attention to indoor air quality recently, and that trend is likely to continue. There is a new emphasis on comfort over energy efficiency, especially in humid climates like Florida and Alabama. As such, HVAC techs can expect an intersection between the HVAC industry and the building science industry. Customers also enjoy having integrated controls, such as thermostats that connect to wi-fi. However, some service companies and manufacturers have focused too much on shiny new technology. Bryan owes this phenomenon to the "sales-first" business model. He would prefer to see techs and manufacturers focus on basic serviceability. As such, Bryan would like to see an emphasis on creating thorough solutions to problems instead of seeking quick fixes. In the future, Bryan hopes to see further development of tools like measureQuick. He would love to see better data collection practices. He would also like to see more unified communication protocols between appliances. Bryan and Chris also discuss: Solar solutions Human comfort and IAQ Communication between techs in the digital age New ASHRAE outdoor air standards "Sales-first" business models and the skills gap How to make the HVAC industry appeal to the new generation How to find fulfillment and validation in HVAC work   If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In today's podcast, Chris Reeves joins Bryan to discuss filter driers, including suction driers, liquid driers, core driers, different media, and basic applications. Filter driers are simple components, but they have plenty of room for misunderstanding within our trade. We refer to Parker-Sporlan Bulletin 40-10 throughout the podcast, and you can read that bulletin HERE. Above all, filter driers act as filters that prevent debris from reaching the expansion valves and destroying them. As such, the best place to install a liquid filter line drier is as close to the expansion valve as possible. These filter driers also catch and hold water from the system; they minimize moisture to keep HVAC systems functioning properly. Filter driers also catch and remove acids from the refrigerant circuit. A filter drier and its desiccants CANNOT remove non-condensable gases. However, filter driers should NOT be the primary method of removing moisture. Proper evacuations with deep vacuums should be the main method, as filter-driers are limited in their moisture removal capacity. You also don't want to use a filter drier that has been exposed to atmosphere any longer than a few minutes; the drier has had time to collect moisture and will be less effective. Each time you open up a system, removing the filter drier is the best practice. We use biflow filter driers on heat pumps. The refrigerant can flow in both directions; a check valve directs the flow, so the flow always goes through the core and filter pad the same way, regardless of operation mode. Suction line filter driers are for older HVAC systems with issues. You'll want to install them close to the compressor for maximum protection and watch the pressure drop across the drier. We also discuss: Temperature control Overheating driers and exposing them to heat HH-style filter driers (with activated carbon) System sizing as a consideration Burnout and contamination   If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In today's podcast, Bryan covers the four basic gas laws and how they apply to you as an HVAC technician in the field, not just in theory. Remember, when dealing with pressure, you must convert the units to PSIA, not just PSIG. To do that, you merely add 14.7 to your gauge pressure. In every equation, the "1" indicates an original value, and the "2" indicates a new value. The simplest of the gas laws was discovered first, Boyle's law. The law states that there is an inverse relationship between absolute pressure and volume. When a gas's pressure increases (such as via compression), you decrease its volume. Inversely, when you decrease a gas's pressure, that gas will expand, and its volume will increase. Mathematically, the law looks like this: P1 x V1 = P2 x V2 Charles's law focuses on volume and temperature. This gas law states that volume and temperature rise or fall together so long as the pressure stays the same. You can mathematically describe the law with the following equation: V1 / T1 = V2 / T2 The general law of a perfect gas combines Boyle's and Charles's laws. You can mathematically describe the law like this: (P1 x V1) / T1 = (P2 x V2) / T2 As HVAC technicians, we should care about the gas laws because our pressures and volumes will change as temperature changes throughout the day, such as when doing a standing pressure test with nitrogen. Nitrogen is a relatively non-reactive gas, so it will follow the gas laws and won't condense to a liquid or react with other chemicals. Dalton's law is the final law, and it states that the combined pressure of all gases in a closed space is equal to the sum of the individual gas pressures.   If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Alex Figueroa is a VRF and refrigeration tech in Puerto Rico, and he talks to Bryan about his work and specialized experiences. Since Mitsubishi is a forerunner in the ductless industry, many of the units that Alex has worked on are Mitsubishi units. Alex works on lots of ductless mini-splits and VRFs in central air in commercial buildings. He typically works on VRF units that have ceiling cassettes or fan coils. Some VRF units also have branch boxes with electronic expansion valves (EEVs), and those components help distribute refrigerant flow. These systems have expansion lines, which some technicians may confuse for liquid lines. As with other large commercial HVAC units, oil is also a concern in VRF systems. Smaller-tonnage systems have large accumulators, but larger systems may also have large separators. Some of these systems are large and may contain 200-300 pounds of refrigerant. Unlike many other HVAC units, these systems have an electronic interface that indicates superheat, subcooling, and other criteria that can help with charging and troubleshooting. (Techs can, however, hook up gauges at the condenser, but the practice is not often necessary.) When you open up a VRF system for the first time, you will see lots of solenoids and other components that resemble refrigeration parts. Therefore, Alex felt that his experience as a refrigeration technician benefited him as he began working on VRFs. Like heavy refrigeration (especially grocery refrigeration), VRF systems may have several compressors and refrigerant circuits in a single system. Digital scrolls are common compressor types for these systems. The greatest maintenance issues with VRFs deal with are dirty evaporator coils and filters. In Alex's experience, the electric controls are the most commonly failed component. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

What do you need to know to walk up and fix a VRF or ductless system? John Chavez, longtime VRF/ductless pro, covers his approach to ductless and VRF diagnosis in Part 2 of this podcast. (Listen to Part 1 HERE.) If you believe that there is a component failure, you'll want to check the voltage going into the unit. You'll want to pay special attention to the board and see where power is going in and out. In other words, pay attention to your inputs and outputs on the board and pay attention to the documentation in the manual. Make sure you have a quality voltmeter on hand. Another potential electrical issue occurs when the board blows out entirely. When that happens, you'll have to watch the input voltage and be mindful of the utility quality and local geography. Utility companies WILL NOT admit if they are part of the problem, so it is good for a technician to ask about the property and utilities to study the history of the unit and the location. Watch your discharge air temperatures and make sure they perform correctly under AHRI conditions (the standard is 95 degrees outdoors, 86 degrees indoors); should have 40-50 degrees coming out of the discharge of the ductless unit. Pipes may even get as cold as 37 degrees before discharge protection kicks in. To sum everything up about VRF diagnosis, you'll want to do whatever you can to find the root cause; don't be a parts-changer. To consider all possibilities, you must take your time to understand the unit. We also discuss: Lightning strikes and power surges Determining delivered capacity Critical charge Electrical/controls terminology Building science, thermal envelopes, and VRF performance Sensible and latent heat loads Inverter-driven compressors Resources Computer Room Application Formula Ductless Steps Friedrich Service Form Seven Common Install Answers If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

This episode covers some basics of matter that relate to HVAC/R. These basics include mass, weight, and volume. There will also be some talk of specific gravity and specific volume. Matter and energy are the building blocks of the HVAC industry; we move matter around and transfer energy. Matter refers to anything that exists and takes up space, including all solids, liquids, and gases. We use three means of measuring matter: volume, mass, and weight. Volume refers to how much space an object occupies. Even though we use mass and weight interchangeably, they mean two different things. Mass refers to the amount of matter an object has, and weight is the force exerted on an object by gravity. Density is a mass-to-volume relationship. Density comes into play when items float or sink in water, and it is a component of specific gravity. Specific gravity does not have an absolute unit of measure; it merely compares an object's density to water. For example, propane has a specific gravity of 1.5 in comparison to air and would sink. Conversely, natural gas has a specific gravity of 0.6-0.7, meaning that it would float in air. Specific volume is NOT relative; we use a set unit for it, typically cubic feet per pound. The cubic feet of air per pound changes with temperature, humidity, and barometric pressure. So, "standard air" isn't a fixed value. All gases can be compressed and can be affected by temperature much more easily than the other states of matter. Specific volume is important because it helps us determine the amount of refrigerant we can safely put into a recovery tank; you must know the difference between the specific volume of water and the refrigerant you are using.   If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

What do you need to know to walk up and fix a VRF or ductless system? John Chavez, a longtime VRF/ductless pro, explains his approach in Part 1 of this podcast. You CANNOT have a haphazard approach to installation or service. The best thing you can do is respect VRF and ductless technology for what they are. When you take the time to understand the equipment and the processes at work, you will be successful. The best thing you can bring to a job is patience. Unlike on typical split systems, gauges should NOT be hooked up to a ductless or VRF system unless they are absolutely necessary. Gauges may introduce contaminants into the system, and they may cause more harm than good if techs use them when they are unnecessary. Superheat is rarely a useful diagnostic reading for mini-split and multizone systems. However, superheat and subcooling are readily available readings that may be useful for diagnosing VRF systems. Diagnostic work requires detective work; ask questions about the system history to see how it has performed in the past. Involving owners in the repair process is a good way to build a relationship while understanding the problem better. Like split systems, dirty coils and air filters can severely compromise a VRF/ductless system's performance. So, try to make sure filters and coils are all clean during diagnosis. The fins of evaporator coils can get especially dirty and should be cleaned. Some ductless systems can be cleaned in place. Be sure to take down the model and serial numbers of the system. If you need tech support, you MUST have those numbers to be as specific as possible. Service and installation manuals are also useful tools for diagnosis (yes, we know that some techs are allergic to reading). However, don't over-rely on the error codes. Resources Computer Room Application Formula Ductless Steps Friedrich Service Form Seven Common Install Answers If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Watch the sequel to this podcast episode HERE.

Frank Besednjak talks about proper communication in conflicts between techs and managers. He also covers the potential problem with inexpensive air conditioning maintenance specials. When it comes to communication, Frank is a proponent of honesty and straightforwardness. However, he understands and appreciates the fact that people have different communication styles. He encourages people to write down their ideas, whether those ideas benefit the company, themselves, customers, etc. Frank encourages managers to set up an email or text line for people to input their ideas via written media; the leaders should make employees feel empowered to become part of the solution. The difference between a committed and complaining employee will become clear in the way that they communicate suggestions. Cultivating positivity in the business starts with future-oriented leaders. Managers who focus on the past allow negativity to breed, especially when they fixate on poor performances in the past. Frank also suggests that managers take the "good in public, bad in private" approach when discussing employee performance. The point is to find solutions, not make employees feel bad. Some PM "specials" include the infamous $89-tune-up. Some techs use these PMs as opportunities to push products and make sales. Frank believes that the pricing is not the issue; dishonesty about the tune-up's intentions is the issue. Sadly, these "specials" are often scams, but they still work for bringing in business. Some companies even do "classes" that are truly sales meetings; those meetings teach techs how to upsell and push products. This practice also opens the door for honest, skilled techs to be replaced with salespeople who do not fix units as they should. Frank recommends implementing a good pricing strategy that lets customers make their own decisions. Then, you will attract business honestly.   If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Carter Stanfield, a co-author of Fundamentals of HVACR, talks about the entire refrigeration circuit. He also explains how to read and plot a pressure-enthalpy diagram. The refrigeration circuit has four main components: evaporator, compressor, condenser, and metering device. When teaching, Carter likes to explain that boiling is a cooling process and condensation is a heating process. He describes saturation as the breaking point at which liquid refrigerant can no longer hold more heat (in the evaporator). The superheated vapor from the suction line then enters the compressor; the compressor adds even more superheat. So, the discharge line has very superheated vapor. In the condenser, saturation occurs when the vapor cools to the point that it can no longer hold more moisture; the temperature stays the same until the refrigerant becomes entirely liquid. Subcooled liquid travels to the metering device via the liquid line. The metering device reduces the pressure of the refrigerant and feeds the evaporator. However, some flash gas occurs and helps drop the temperature of the remaining liquid. A pressure-enthalpy diagram illustrates the refrigerant's changes in and out of the saturated state as it moves through the refrigeration circuit. The chart looks like a curved dome, and saturated states are inside the dome. Pressure is on the y-axis, and enthalpy is on the x-axis. Pressure is a logarithmic arrangement; a linear arrangement would be impossible to plot. The bottom of the chart shows low pressures, and the top shows high ones. Enthalpy is the heat content of the refrigerant. We express it in BTUs/lb. When you plot one of these diagrams, you can start with four lines and readings: high and low-side pressure, suction line temperature into the compressor, and liquid line temperature into the metering device. You will end up drawing a parallelogram shape on the chart.   If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

James Bowman talks to Bryan about leak sealant products, including RectorSeal's Leak Freeze product. James talks about how sealants work, what happens when they don't work, and how to be open-minded without being gullible. Leak sealants must not react adversely with the components inside a system (oil and refrigerant). Just as mineral oil caused some issues with O-rings, POE oil has additives that cause acid to form on the system. RectorSeal's Leak Freeze is technically an oil that can work with the oil and refrigerant that already exists in an HVAC system. Leak Freeze is a high-performance lubricant that creates a soft bond around a leak and doesn't clog the system. Many refrigerant-based polymer leak sealants are hard chemicals that technically succeed at sealing leaks. However, these leak sealants are prone to clogging a system when they clot together (via flocculation). If a sealant has hazard pictograms, then there's a good chance it is a refrigerant-based sealant that creates polymers. When selecting a product, there will always be pros and cons with each product category. There are cases where each type makes sense; you must know your customers, business, and employees to determine the best choice for each unique situation. In a test that Bryan performed with Leak Freeze on a rubout leak on the high side of the system, he noticed that the sealant managed to stop the leak while the system ran. Then, the system shut off. After that, there was only a slight leak. Generally, the product was meant to work better on formicary corrosion on the low side, but it still proved to be effective at sealing a leak in a challenging location.   If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Dick Wirz, author of Commercial Refrigeration for Air Conditioning Technicians, talks about making the switch from A/C to refrigeration. Dick Wirz is an advocate for using rules of thumb, which is a controversial position. However, rules of thumb are an excellent way for A/C techs to dip their toes into the refrigeration world. Rules of thumb are less likely to overwhelm technicians than the exact technicalities of certain readings and measurements. Some prime examples of using rules of thumb in air conditioning are condenser split, evaporator split/TD, subcooling, and superheat. Those all have relatively neat "rules of thumb" that don't vary too much. (30-degree condenser split, 35-degree evaporator TD, 10-degree subcooling, and 10-degree superheat.) On medium-temperature refrigerators, a common rule of thumb is a 10-degree TD for a 35-degree box with an evaporator running at 25 degrees (35 - 10 = 25). On low-temperature applications, the box temperature is -10 degrees. You still have the 10-degree TD, so the design conditions for the evaporator would be -20 degrees (-10 - 10 = -20). The pressures will vary across refrigerants, but the temperatures WILL REMAIN the same as the rule of thumb. Ice is an alarming sight for residential technicians. However, commercial refrigeration technicians will occasionally see frost or ice under perfectly normal circumstances. Frost merely indicates that the temperature of a pipe is below freezing. Ice alone does NOT indicate floodback. In commercial refrigeration, the fans run all of the time to defrost the system (even during the off cycle). However, in freezers (low-temperature refrigerators), hot gas or electric defrost is required. Dick also talks about: Subcooling vs superheat in diagnosis R-410a pressure confusion Reach-in and walk-in refrigerators Medium and low-temperature refrigerators Defrost controls Common issues in commercial refrigeration   If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Camron Conlee joins the podcast to give us an introduction to ammonia chillers. He also explains what it's like to work with a poisonous refrigerant. The California division of TDI Refrigeration, where Camron works, primarily works on ammonia systems. We often see ammonia refrigeration in cold storage and food processing; ammonia refrigeration is usually in industrial applications away from the public. Ammonia is more hazardous than CO2 and other refrigerants because it is toxic. When working on ammonia chillers, the most important thing is to keep the ammonia inside the pipes. You may even need to wear full-face respirators and personal monitors when working on potentially leaky ammonia systems. Ammonia chiller oil systems are a bit different from R-22 systems. Oil separation is important in both ammonia and R-22 refrigeration, as ammonia systems typically use coalescing separation methods to isolate oil from the refrigerant. However, the oil generally doesn't mix with ammonia as readily in the first place. Some systems rely on pressure differentials to move liquid, and others use pumps to move liquid ammonia into the evaporator. Preventive maintenance on ammonia systems is quite similar to PMs on other types of refrigeration systems. Compressors are also important components that require occasional maintenance. Like many other commercial refrigeration systems, several ammonia chillers have hot gas defrost. The ammonia refrigeration world has a few different types of job opportunities. Some companies require in-house operators, but there are also external service companies, which may have a few smaller customers. In almost all cases, these jobs require technicians who can stay calm in crisis situations, as there is a lot at stake. Camron and Bryan also discuss: Recirculated vs. gravity-fed systems High vs. low-pressure receivers Dry vs. wet suction Screw compressors Copper and brass leaks Finding ammonia refrigeration companies and trade schools   Find out more about TDI at tdirefrigeration.com. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Adolfo Wurts from Arbiter Incorporated, designer of the UEI WRS line of Bluetooth scales, comes on the podcast. We talk all about scales and how to use them. You'll want to pull a scale off your truck every time you add refrigerant to a system. Many technicians choose to estimate how much refrigerant they have to put in, and they sometimes put in more refrigerant than they estimated in their quote. Consequently, the business loses money. You'll also want to weigh your tanks during EVERY recovery to ensure that you do not overfill your recovery tanks and risk hydrostatic pressure buildup. Weighing the charge also helps keep track of amounts of increasingly uncommon and expensive refrigerants, such as R-22. Also, make sure your scales have good batteries at all times! Weighing the charge also shows you where previous technicians may have overcharged or undercharged the system to rectify a different issue. For example, someone may have starved their unit to reduce head pressure (maybe the condenser coil caused the high head pressure all along). To get the most accurate measurements possible, you must assess the quality of your scale and how you use the scale. For example, your scale must be on hard, level ground. (Do not use scales on grass; opt for concrete instead.) You should also center the tank you are weighing. However, the UEI series typically shows little variation under undesirable circumstances. (That is still not a reason to be careless with your scale.) UEI WRS scales are rugged and excellent for brutal fieldwork and inclement weather conditions. The scales also connect to smartphones via Bluetooth so that you can view the measurements remotely. The WRS series also has a wide range of design features for ease of use.   You can find these scales for sale at TruTech Tools by going HERE. And don't forget to use the coupon code "getschooled" for a discount at Trutechtools.com. Find out more about the WRS line by visiting the UEI website.

In this quick announcement I talk about the launch of the revolutionary diagnostic and data management tool MeasureQuick

Todd Liles of Service Excellence Training joins the podcast. He talks about techs who shouldn't be on commission, how to make the most of your career, and facial hair profiling. Todd's skillset was mixed; he had some technical knowledge, sales experience, and communication skills. He took those skills into training, and he started his own business based on his skills; his first business didn't pan out, but he founded Service Excellence Training and has grown quite a bit. Todd develops technicians by teaching them best practices, which also boosts sales. In the past, some technicians have judged Todd because of his sales background; technicians and salespeople may have negative views of each other due to bad experiences with them. If we want technicians and salespeople to improve their lives, we need to be able to listen to each other and set aside our biases. Some technicians may resent performance-based pay and argue that it gives sales techs a motive to take advantage of others. The truth is that most of us are simply hardworking people who want to do the right thing for customers. Working for performance-based pay doesn't suddenly make them unethical. In any case, techs can maximize their value by doing best practices and benchmarking the system; collecting data will make a technician more effective and more invested in the client's system and overall best interest. When it comes to sales, facial hair profiling is very common. The clean-shaven look is a staple of sales technicians, but the training is much more important for sales success. Todd and Bryan also discuss: Service Excellence Training core truths of service Having a rough childhood and making good vs. bad choices Flat-rate vs. performance-based pay Disorganized technicians and where they might shine Dealing with paperwork Uneducated technicians vs. shysters  Facial hair policies   Learn more about Todd's work at servextra.com. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Jim Bergmann returns to the HVAC School podcast to cover some advanced topics in evacuation, including rig setups and triple evacuation. To increase the speed of evacuation, you need two large-diameter vacuum hoses to overcome the limitations of pressure. Core removal is also critical, as Schrader cores are a significant restriction. It's also unwise to use a manifold for evacuation; a manifold will double your hose length, provide a restriction, and serve as a leak point. The vacuum pump is full of opportunities to expand your advanced evacuation knowledge. The pump oil needs to stay clean, and Jim recommends changing the oil after every use. When it comes to pulling the vacuum, it's worth noting that the vacuum is deeper at the pump than at the system itself. The vacuum at the pump does NOT reflect the vacuum at the system; core tools can isolate the vacuum pump from the system so that you can measure the true vacuum at the system. When we "break" with nitrogen, we're referring to nitrogen sweeps at different stages of evacuation (especially in the case of a triple evacuation). Triple evacuations are rarely necessary nowadays, but you may need to break with nitrogen from time to time. Nitrogen moves through the system so quickly that breaking with nitrogen often has a minimal impact on the vacuum. The length of evacuation doesn't really affect dehydration until you get below about 300 microns. Dehydration has more to do with the strength of the vacuum than its length. Jim and Bryan also discuss: Locking refrigerant caps Assembly lubricants Outgassing odors and gas permeability Hygroscopic vs. hydrophobic vacuum pump oil Vacuum pump oil management Average air conditioning decay rate Thermistor vacuum gauges Nitrogen regulators Metering devices Gas ballast on vacuum pumps   If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In this episode, Brent Ridley talks about the flame-free ZoomLock fittings and why he is using them for almost everything to replace brazing. These are tools from Parker, and they can give you leak-free fittings within seconds. ZoomLock works in residential and commercial applications. The fittings come in a wide range of sizes for the large piping of VRF systems and the smaller copper tubing of residential A/C suction lines. Brent measures the tubing to make sure there's enough room. Then, he cuts the bell end off, deburrs the copper, sands the copper down, and applies the fitting. You do NOT have to apply a lubricant or anything before you add the fitting. The fittings have two grooves to match the grooves on the jaw; that is how the fitting can crimp properly. Brent likes ZoomLock for its time-saving potential. You don't have to get your oxyacetylene (or air-acetylene) rig prepared and spend time brazing. There is also the potential to save money on the fuel and nitrogen you would use while brazing. As technology improves and the price goes down with increased production, it's possible that we can see ZoomLock-type fittings in more applications. Brazing is a key skill, but it also comes with a lot of risk to our bodies and customer property, so ZoomLock is a promising replacement for brazing. Will ZoomLock replace brazing altogether? Probably not; it would be quite difficult to use those fittings on a reversing valve, for example. But is ZoomLock a nice tool to consider for some applications? I think so. Brent and Bryan also discuss: How Brent was introduced to ZoomLock Stub lengths Oil compatibility (POE vs. mineral oil vs. refrigerant) Lateral strain on fittings Filter-driers   If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Jeff Neiman returns to the HVAC School podcast to explain how we can perform leak detection on a low-pressure chiller. Jeff works on systems with glycol loops or other forms of secondary fluids, which may have leaks from time to time. When the chilled water pump on the suction side runs into a vacuum, air can get into the system via the shaft seal. Then, more leaks can occur in the glycol loop as more air goes into the system. High-pressure chiller leak detection is pretty much the same as on a package unit. However, your typical low-pressure chiller will sit in a vacuum and require us to spend more time on leak detection. These low-pressure systems often have massive amounts of refrigerant below atmospheric pressure. These may have purge units that keep non-condensibles out, but some trace amounts of refrigerant can be vented out with the non-condensibles. Leaks on the low side of the system can cause even more refrigerant venting. Leak detection on the condenser side of a low-pressure chiller is pretty straightforward; like high-pressure chillers, you can use the same leak detection methods you'd usually use on a package unit or split residential system. When you know you have a leak on the low side, you can turn the chiller off; it will still be below atmospheric pressure, so you'll need to bring up the pressure to find a leak. Otherwise, you can weigh out the charge and flow nitrogen with trace amounts of refrigerant through the system. Overall, leak detection can take a LONG time on low-pressure chillers. Jeff and Bryan also discuss: High vs. low-pressure centrifugal chillers Raising the pressure on the low side Submerging leaky components in water Leaking in the tubes Pressure and its effects on gaskets Jeff's leak detection tools Open-drive motors   If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In this episode of the podcast, Jim Bergmann talks about the launch date of the measureQuick (MQ) app, what it will do, why he made it, who it is for, and why it's different than anything else that came before. MeasureQuick is a universal measurement platform that incorporates Bluetooth to display, store, and interpret measurements. The initial release focuses heavily on air conditioning, but its goal is to assist with combustion analysis and refrigeration readings. It is a troubleshooting assistant that saves time and helps technicians make sense of their readings. It combines the air side, refrigerant side, and electrical side in a single Bluetooth-connected technology. MeasureQuick helps technicians understand if the conditions are ideal for testing or if the system performs optimally while testing. The app does not automate the diagnostic process, but it is a diagnostic aid to help reduce callbacks. MeasureQuick contains both free and paid components for users, and it is backed by Testo and other sponsors. Jim Bergmann's app brings a technological appeal to the tech-savvy rising generation. MeasureQuick encourages curious technicians to understand their readings and diagnostic criteria. The goal is to modernize the HVAC industry while bringing the knowledge base of the older generation to the newer generation. Jim Bergmann's goal is to make the app TEACH its users the best practices and principles of the industry; he aims to make information accessible to technicians with varied learning preferences. This app is especially useful for those who are not avid readers. Of course, hacks who don't care about learning the correct way will always exist. However, MeasureQuick will hopefully bring accountability to our industry through education.   You can find out more by going HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

James Bowman of Rectorseal returns to the podcast to discuss condensate switch codes and some best practices to comply with the codes. The humble condensate switch actually has installation standards; although there isn't a "law" about the codes, many areas follow and enforce the contents of the International Mechanical Code (IMC). Some states, including Florida, also adopt elements of the IMC and amend it to create a set of guidelines for the state. The IMC has widely-enforced code 307.2.3.1, which states that water-level monitoring devices must be installed in the primary drain pan; the device shall shut off the equipment. This code applies to downflow units and all other coils that don't have a secondary drain pan or provisions to install an auxiliary drain pan. The code also states that devices installed in the drain line are not permitted. However, code 307 is actually NOT saying that you can't install a switch in the secondary port at all; there are four different ways to comply with the code without installing a condensate switch in the primary drain pan. Switches must comply with UL 508. However, there are plenty of non-compliant switches on the market. These may even say that they "conform" to UL 508. Compliant switches will generally not short out when dropped in water, but it's up to us to make sure we're using code-compliant switches. If you're installing a float switch, be sure to follow the instructions; that's usually the best way to comply with local codes and protect the equipment. As always, make sure you test the switch before you leave the job site. James and Bryan also discuss: Mini-split drain considerations Float switches in the primary drain line Piping auxiliary floats Testing safety switches for heating equipment Drain pitch Rectorseal condensate switches Keeping redundancy in mind Condensate switches for RTU and ductless units   If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Les Fork returns to the podcast to discuss on-call rotations. He explains why being on call is necessary and how you can make the most of it. We are supposed to be on call for the sake of customer service; when a customer has an emergency, it's best for the customer (and the business) when someone is available to respond to the emergency. Of course, many of us dread being on call (although the paycheck might be quite nice). You may only have one or a few techs on call, so it can be difficult to take on all of the customers each day. Although it's generally okay to speed up a bit and be less thorough, you should still be working to fix the issue at hand and tell the customer if the system needs further inspection in the future; it's also a great opportunity to propose a maintenance plan. The system should be working, the compressor should be running, and the capacitor should not be over-amping. Some companies may offer 24-hour service, and others may not. If your company offers 24-hour service, you may indeed be on call at all hours of the day and night. It makes more sense to offer 24-hour service to commercial customers, though you can certainly offer it to a residential market. Overall, it might not be best to advertise 24-hour service because you may draw in price shoppers. (You're also at liberty NOT to offer service after hours.)  Les and Bryan also discuss: Managing anger and being professional Empathy Billable vs. non-billable hours Order of inspection Scheduling and prioritizing customers Walking customers through frozen coils Money talk: warranties and call-out fees Cleaning drains Tip ethics and etiquette Collecting payment   If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In this podcast episode, Jim Bergmann continues talking about standard air, air density, and mass vs. volume as well as some other methods of "directly" measuring airflow. It gets pretty deep. Airflow hoods and vane anemometers can give you direct airflow measurements. You use static pressure probes, not pitot tubes, to measure TESP. When measuring static pressure, you put the negative probe in the return and the positive probe in the supply. Then, you measure the TESP (away from wiring and airflow). However, air pressure fluctuates as that air moves in the duct. Velocity pressure occurs when air moves and creates turbulence. The blower moves air, which has weight. As such, density, volume, and mass are all important as well. As air density changes, the CFM remains constant at a variable mass flow rate. When it comes to using any tool for measuring airflow, static pressure, etc., all tools are an investment of money and time; you must spend some time learning how to use those tools. You will discover those tools' limitations and must learn how to work with or around those limitations.   If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Bill Spohn Jr. is a college intern working towards his business degree, but he took a week to see what it is like to work as an HVAC tech. He shares his impressions on this podcast. Bill is the son of Bill Spohn and has been a college intern working with TruTech Tools. However, he has just gotten his first real dose of the HVAC contractor experience in the full swing of summer. Bill started off by riding with a Kalos residential tech, Tyler, who had seven calls that day, mostly for PMs; they worked from 8:15 to 9:00 PM. Bill was impressed with the professionalism of Tyler and how well he communicated with customers. The second day, Bill got to do an install, which was a physically taxing task (partially due to the Florida heat). He put in a new drain pipe, new copper tubing, a new air handler, and some new pieces of ductwork. Bill also spent a day with Jeff, where he did a lot of preventive maintenance.  As with many people, Bill learned a lot about the importance of refrigerant and proper charge. He also found SEER ratings and other efficiency measures fascinating. Bill went into his experience with the idea to identify "pain points" for techs and suggest improvements to current tools and technology. Now that Bill knows what's important to techs in the industry, he can bring ideas to TruTech Tools to make the techs' lives easier and address the "pain points" that many contractors have to deal with. Bill and Bryan also discuss: Tyler's past Working on trailers or mobile homes Organization (or lack thereof) in vans and tool bags Combined analog and digital gauges  Inventory tracking systems Possible Testo 115i temperature clamp improvements   If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In this two-part podcast series, Jim Bergmann talks about measuring airflow in HVAC systems. He covers a wide range of airflow measurement instrumentation and readings. In this first episode, Jim covers ECM motor considerations, delivered capacity, laminar flow, and more. In the HVAC industry, many techs confuse static pressure for airflow. Although you need static pressure to have airflow, it is NOT airflow and can fluctuate rather wildly depending on the duct conditions. Static pressure is an indirect airflow measurement. Airflow is actually a measurement of velocity (such as with pitot tubes) that you then convert to a volume measurement (CFM).   If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In this podcast episode, Bryan talks about brazing basics and tips. He goes over safety, regulator settings, torch positioning, flowing nitrogen, heat control, and more. Whenever you're going to be working with equipment that creates fire, you will want to make sure you know all of the safety procedures and have appropriate PPE. Make sure your gear is in really good condition; make sure your hoses and regulator have not been damaged. Be sure to have a fire extinguisher handy as well. When preparing copper lines, you'll want to keep things out of them. Make sure oxygen, dust, burrs, and flux can't get into the tubing.  Flowing nitrogen is a best practice, but it's also a staple among the brazing basics. Nitrogen displaces refrigerant, water, and oxygen that might be in the copper lines. Regulators can help you purge with nitrogen at somewhat higher SCFH (20-50) and then flow it at a very low SCFH (2-5). You should hear just a whisper of nitrogen when flowing it. When you set up your torches, it's important that you look at the torch manufacturer's specifications. The tips have different designs for different functions, and it would be wise to read up on their purposes. When setting the oxygen and acetylene pressures, try to keep the numbers the same. Light acetylene first and THEN add the oxygen, and then you'll want to turn off the oxygen first and then acetylene. You'll want a neutral or slightly carburizing flame but not an oxidizing flame. Bryan also covers: Protecting the workspace Unsweating  Reaming copper Reducers, fittings, and swaging tools Nitrogen flow regulator types Wrenches for opening tanks Brazing vs. soldering Brazing/soldering rods Getting the copper hot enough Preventing carbon buildup Leak testing joints

Bryan talks to Ralph Wolf from T&N Services on YouTube and the Working Joe's podcast. We talk about blue-collar life, how the trade has changed for us, and what experience gives a tech that can't be read in a book. Ralph started off doing sheet metal work in the Navy before going into HVAC. He started as a sheet metal installer and learned most of what he knows about HVAC on the job. Taking accurate superheat and subcooling readings have become much more important over the years. We can't get away with "beer-can cold" rules of thumb anymore, especially as MicroChannel and TXVs have evolved and become more prevalent. Efficiency is becoming more important as well, especially due to government mandates. Blue-collar jobs have a ton of best practices for each trade. However, those who have been in the trade a long time typically know the appropriate times and places for those practices. (For example, you don't need to check static pressure on EVERY system, but it's a great idea when you're commissioning a system or working on a system with airflow issues.) As you gain experience, you'll know when to use best practices and when you can bypass them for the sake of time. So, you'll come across two types of senior techs in the trade: those who are plain lazy and those who simply know the exact times and places for best practices. Even though the blue-collar lifestyle very much becomes a part of who we are, we each have a different relationship with the trade. Ralph and Bryan also discuss: The practicality of best practices Corrosion System longevity Airflow problems Understanding individual pieces of equipment Carbon buildup Leak sealants Ralph's YouTube journey Differences between old-school tradesmen and millennials Calling out dishonesty and poor quality   If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

This episode is a rebroadcast of a very useful episode from the Corbett Lunsford's Building Performance Podcast at https://buildingperformancepodcast.com/. Corbett talks to building moisture control expert Lew Herriman about moisture, ventilation, and what happens when you're drying "stuff." When we think about humidity control, we have to ask if we're drying air or drying "stuff." Dehumidification is about drying the air, but many people think about it when they actually want to dry "stuff" like fabrics and other absorptive surfaces often found in residential applications. However, drying out "stuff" does affect how we would dry out the air. Commercial buildings often don't have a lot of absorptive materials, as many have tile floors. Residences tend to have carpet and upholstery, making them challenging cases in building performance. The HVAC system controls moisture, whether they have a humidifier, dehumidifier, or neither. HVAC systems create pressure differences, which contribute to dry air infiltration. Homes heated solely by radiant heat would not be as good at drying the air, but good ventilation could supplement radiant heat. When we have humidity control problems that affect comfort or moisture on absorptive surfaces, we might start thinking about controlling absolute humidity. Absolute humidity refers to the actual moisture content in the air, not the moisture relative to the temperature. However, most homes don't have the ventilation systems that would help dilute the humidity, including HRVs.  Then, when drying "stuff," you have to put heat in to get the moisture out. Corbett and Lew also discuss: Absolute vs. relative humidity Dry-bulb temperature changes and dew point Duct leakage HVAC and building performance strategies for mixed climates Energy-recovery ventilators (ERVs) vs. heat-recovery ventilators (HRVs) Exhaust at the source Dehumidifiers Dehumidifying incoming fresh air Hypothetical makeup air systems for residential applications Comfort metrics   Learn more about Corbett's work at buildingperformanceworkshop.com.

Restaurant HVAC and refrigeration tech Nick Messick comes on the podcast to talk about restaurant equipment, especially the "hot side." The "hot side" refers to equipment that heats the food; it includes often deep fryers but has a lot of variation. The "hot side" also includes specialty equipment for frying noodles and performing other unique functions. In Nick's opinion, the worst service call has to do with fryer pumps due to all of the grease. The grease gets all over tools and your hands, and it can be quite difficult to work on equipment with fryer grease. Other things he dislikes working on are machines that are on their last legs, as many owners are reluctant to replace equipment. Many fryers go through a melt cycle that turns the heat on and off to avoid burning the oil. The flames heat the bottom of the vat using a heat exchanger like a furnace; then, the gas vents into the flue and out the hood. These systems generally use spark igniters and may use either direct-spark or intermittent-spark ignition with a pilot. Nick's favorite call is when fryers make loud popping noises, as it's easy to diagnose and fix; the cause is typically either the ice cube relay or a bad igniter. In grease-heavy restaurant environments, we clean equipment by using cleaners meant for electrical equipment. You want to avoid leaving residue on the equipment and ruining the control boards. The restaurant staff should be cleaning out the fryers themselves, but you may encounter some dirty equipment (and workspaces). Nick and Bryan also discuss: Dishwashers Replacing equipment Flame rectification Circuit boards Electric fryers Drawing the line when it comes to sanitation in HVAC service   If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. P.S. - Don't pull the fire alarm

Phil Zito of Building Automation Monthly comes on the podcast to discuss building automation and what HVAC techs should know about it. Automation essentially refers to control systems; we started off with pneumatic control systems, and then we went to analog and electromechanical control systems over time. Building automation refers to the process of automating controls on a larger scale, such as for an entire building. As long as you can read electrical and mechanical diagrams, you can work on automation systems; you don't need to know about IT or robotics.  Large buildings like malls may require HVAC automation. In other structures like university buildings, you may also end up automating lights and other electrical functions. Automation makes other systems talk to each other, and it does that by controlling on/off schedules and set points. These building automation systems consist of sensors, switches, conductors, and decision-making logic (such as simple desktop servers). Regardless of the automation system, the sequence of operation will always go in the following order: server, supervisory device, field controller, and input/output. A communication bus transmits messages between field controllers; it works like floating controls or pulse-width modulation. You don't need to know the binary communication of the computer; you just need to know how to measure voltage with your multimeter to work on a communication bus. An HVAC tech may also be interested in knowing that building automation has an air side and a water side. These systems may also interface with package RTUs and VAV systems. Phil and Bryan also discuss: How Phil got into building automation Servers User and web interface Resistance vs. analog values Barriers to getting into BAS careers Installation vs. service Taking initiative and being resourceful How BAS and HVAC workers can make each other's lives easier   Visit Phil's website HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In this podcast episode, Bryan and Mike Layton of Shore Distributors explain how HVAC contractors and distributors can build a great partnership. Shore Distributors is a wholesaler in Maryland that carries Carrier, Bryant, and Payne. The job of a territory manager is to help HVAC contractors, so they're there to help contractors. The territory manager's job is to help set contractors and dealers up for success, so they don't feel burdened by questions because it's their job to answer them. Territory managers know that the goal of business is to make money, so they understand the importance of moving boxes and making sales. That said, contractors who move boxes tend to make the rules and have access to privileges. Warranty returns are a bit of a touchy subject; distributors tend to give contractors the benefit of the doubt and are generally willing to replace the part as long as you supply the correct information. However, Mike believes that the 10-year parts warranty has been detrimental to business. End-user satisfaction is a goal we can all strive for. HVAC contractors can be more thorough when completing their jobs and setting up equipment; when installers take their time and explain proper use to the owner, they increase customer satisfaction. When HVAC contractors succeed, distributors succeed and can keep providing service to top contractors. Overall, a healthy contractor-distributor relationship has mutual trust built on dependability. Distributors need to be dependable and available to help the contractors they serve. Mike and Bryan also discuss: A day in the life of a distribution role Ego vs. results Contractors that abuse warranties Vetting techs and holding them accountable Controls What installers can do better Inverter products Understanding each other   If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In this episode, Bryan talks with Jamie Kitchen from Danfoss about why and how thermostatic expansion valves (TXVs) fail and how they function in the first place. As fixed orifices become a dying breed with the development of higher-efficiency systems, TXVs take over the mantle as the primary method of expansion. Expansion valves meter the flow of refrigerant by aiming for a certain suction line superheat value. Unlike a fixed orifice, which has an opening of a constant diameter, an expansion valve adjusts the opening size to the evaporator based on suction superheat readings. TXVs have a sensing bulb, diaphragm, spring, and cap tubes. Various pressures act on these components: bulb pressure, spring pressure, and evaporator pressure. The sensing bulb picks up the suction superheat adjusts its pressure on the diaphragm based on the superheat it detects. Spring pressure and evaporator pressure act against the bulb pressure. The combination of all three pressures (bulb vs. spring + evaporator) dictates the opening of the TXV orifice into the evaporator. The bulb pressure is an opening force, and the spring and evaporator pressures are closing forces. You can cause TXV failure by adjusting it or brazing it in improperly. When too much heat is applied to the TXV, the components inside can warp. Some TXV failures also occur due to contamination. Flowing nitrogen while brazing flushes carbon and oxygen contaminants out and reduces your risk of TXV failure later on. Bryan and Jamie also talk about: TXV anatomy (powerhead, spring, etc.) Internal vs. external equalization Pressure drop across the distributor Subcooling and its relationship with the TXV Solenoid and ball valve (upstream) malfunctions Filter-dryer placement TXV assessment during commissioning Locating restrictions Residential system airflow   If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In this second part of the podcast, Jim Bergmann wraps up the steps to check a system charge without connecting a gauge manifold. You can check the charge without gauges if you use the following process (and know your DTD, CTOA, etc.): Take the dry-bulb temperature. (Let's say it's 70°F in this example.) Subtract the DTD (35°F). Add target superheat (10°F). Check the suction line. It should be 45°F in this example. If your probe senses a temperature that is NOT within 5°F of the temperature you calculated, check the filter, evaporator coil, etc., for dirt. If the system is not dirty, check the charge with gauges.   For a more extensive look at the process in writing, check out THIS article. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In this episode of the podcast, we talk about gauges. Jim Bergmann from Redfish Instruments and the MeasureQuick app explains why you may want to check a charge without using a gauge manifold. (That's not clickbait; if you've already connected gauges to a unit once, you can probably check the charge of that unit WITHOUT gauges moving forward.) HVAC units manipulate temperature and pressure in the refrigerant charge. Heat transfer occurs between the refrigerant and the environment, and various readings indicate the charge level WITHOUT necessarily connecting the gauges. So, you can check the charge if you know the unit's SEER rating, target superheat, DTD, CTOA, and if the unit uses a fixed orifice or TXV. A large portion of checking the charge without gauges deals with "benchmarking" the equipment. You do that by evaluating the system's performance over time and comparing it to the performance when the system was first commissioned. Airflow WILL decrease over time due to components becoming dirty.   If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In this episode, Jack Rise talks about duct design regarding ACCA manual D, friction rate, face velocity, duct velocity, and what is ACTUALLY wrong with flex duct. Manual D causes a lot of confusion for technicians, and most techs have a limited understanding of it anyway. When determining a blower wheel for commercial ductwork, Jack Rise calculates pressure drops for all of his elbows in the ductwork and makes his decision based on those calculations. Residential HVAC is a bit trickier, and that's where Manual D calculations come in. Luckily, many software nowadays, including Wrightsoft, can calculate loads very precisely and help you with duct sizing. Just as with heat and pressure, there must be a velocity differential if you want air to move. If you need to move more BTUs of heat, then you need to move more CFM of air. Air also tends to take the path of least resistance. Trunk and branch design velocities must be different if you want any control over where the air goes. Trunk duct velocity typically stays between 700-900 CFM, but branch velocity can change quite a bit when you change the locations of the registers and grilles. Branch velocity tends to be 400-600 CFM. Good face velocity can be achieved by choosing the correct register and putting it in an ideal location. Flex duct is not a bad material, but it is controversial due to its reputation for being poorly handled. Manual D has an appendix on compression and sag, and techs who consult it will design a much better duct. Jack also discusses: Available static Choosing a blower and factoring friction rate Oversized ducts Compression, sag, and bends in flex duct   You can find the book at http://www.acca.org/store If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In this episode, Bryan speaks with Eric Shidell about some of the basics of system freezing, what causes it, and what to do about it. Freezing is a normal part of some equipment, such as low-temperature freezers and outdoor units on heat pumps. On straight-cooling systems, freezing is NOT normal and indicates poor operation. Ice formation starts on the evaporator coil and may spread to the compressor via the suction line. The best way to remove ice and defrost the system is to pull the disconnect on the outdoor unit but let the indoor fan keep running. Or, you could turn the unit off but leave the fan on. The goal is to defrost slowly and steadily. Defrosting too quickly could potentially cause damage. Horizontal air handlers in the attic can flood the home if ice forms and melts off too quickly. In an upflow furnace, defrosted ice could damage the electrical components. You will typically find low suction pressure on frozen systems. Many technicians who merely attach gauges and don't thoroughly inspect the unit for freezing will mistake the low pressure as a result of a low refrigerant charge. However, low pressures are a SYMPTOM, not the cause of freezing. Freezing is generally caused by poor airflow over the evaporator coil. As frost appears on the evaporator coil, airflow will be further impeded. On top of that, the suction pressure drops even more. From there, all of these factors feed each other and cause the frost to snowball out of control (almost literally). Sometimes, coils may freeze due to low refrigerant, but the amount of ice will typically be minimal compared to freezing that occurs due to an airflow issue.   If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Corbett Lunsford from the Building Performance Workshop and the Proof is Possible tour talks to us about the moral superiority of building performance testing, blower door testing, and much more. Building performance and HVAC have been becoming much more closely linked lately. So, it's a good idea for HVAC techs to learn a bit about building performance. In the HVAC world, we often see homes with extremely hot upstairs portions and cool downstairs questions. That is a complex building performance issue. A good contractor can troubleshoot the issue with the building and find cost-effective ways to improve the enclosure (air ceiling and insulation) and the HVAC. The construction and improvement industries will be utilizing diagnostics and metrics, much like most of the HVAC industry today. (Metrics that we use include static pressure, superheat, subcool, etc.) The blower door is the most important tool for diagnosing issues with the enclosure. Many odor and comfort issues deal with ventilation, not just the HVAC. As such, blower door testing can help diagnose issues that don't go away after improving or repairing the HVAC system. Air leakage is the most important issue that occurs with the enclosure. A blower door test replaces the front door with an airtight shroud with a fan mounted inside. That fan then hooks up to a manometer to measure pressure in the home with reference to the outdoor pressure. The blower door drags the pressure down to 50 pascals, and then you can see how much air goes through the fan at that constant pressure. The air that comes through the fan indicates a lack of airtightness in the home. However, blower door testing requires practice and repetition. If you get one, practice with it before you use it for diagnosis.   If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In this episode of the podcast, Bryan talks with Andre Patenaude from Emerson about CO2 refrigeration, and transcritical booster systems. Modern CO2 systems are efficient and effective due to their electrical controls and components, including case and high-pressure controls. Carbon dioxide (CO2) is a good refrigerant to address global climate change. From a sustainability standpoint, carbon dioxide is a superior refrigerant to HCFCs and HFCs. Carbon dioxide is also an A1 refrigerant, meaning that it is non-toxic and non-flammable. It is also inexpensive and compares to HFCs in cost. Unfortunately, it can rapidly change pressures and is more efficient in lower ambient temperatures. Overall, CO2 is a desirable refrigerant as we address the challenge of sustainability but is not without its challenges. During the refrigeration cycle, carbon dioxide's critical point comes into play. In hotter ambient temperatures, the carbon dioxide's temperature and pressure may exceed the critical point. The refrigerant then becomes a supercritical fluid; the pressure and temperature change independently of each other. Accessing the supercritical zone is also known as "transcritical." Carbon dioxide refrigeration is best for low-temperature grocery refrigeration. It has also worked its way into industrial refrigeration. However, the greatest challenge revolves around the condensing temperature. Carbon dioxide must reject its heat to something that is much colder than it. A transcritical booster system's condenser becomes a gas cooler in the summer; instead of leaving the condenser as a liquid, a CO2 system leaves the gas cooler as a supercritical fluid. It becomes liquid when it passes through an electronic expansion valve (EEV) before the receiver. The CO2 refrigeration system also contains a flash tank and a bypass valve. The bypass valve partially dictates which compressor the refrigerant fluid travels to. There are also low and medium-temperature evaporators and compressors. Resources Seven Keys to Servicing CO2 Systems - Article by Andre CO2 Booster Systems Introduction - Article by Bryan Cascade Refrigeration - Article by Bryan Emerson CO2 Application Guide

In this just-for-fun episode, we celebrate 10 years of great tools and excellent customer service with TruTech CEO Bill Spohn. We hope you enjoy this lighthearted episode with some discussions about company culture, superior service, and a commitment to quality. TruTech's approach to service goes more beyond selling the tool. The engineers at TruTech aim to learn how technicians plan on using tools. Those engineers want to use their technological expertise to create products that make technicians' lives easier in the realm of diagnosis and measurement. TruTech Tools also works to honor its relationship with the HVAC community and market. The engineers at the company see the value in the relationship between HVAC and building performance. TruTech Tools also carries trusted brands, such as Testo and Carrier. When it comes to pricing, TruTech Tools believes in pricing based on the market price and backing up the product with superior service. Most of a product's value comes from the seller's service. TruTech Tools also remembers to reward loyal audiences and buyers with discount codes or rewards systems. Bill Spohn also wants TruTech Tools to develop some more educational materials in the future. The company has a close relationship with the HVAC industry and wants to show its support through a commitment to training. Overall, TruTech Tools values its connection with the HVAC community and takes pride in its standing as a trusted tool provider for such a great community.   Check out TruTech Tools at trutechtools.com and use the offer code "getschooled." If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE. Check out our handy calculators HERE.

In this episode, Bryan talks with HVAC products designer Adolfo Wurts about technology, automation, and the coming robot apocalypse. Automation is a fear in many industries, and the HVAC industry isn't alone. Today, we talk about how instrumentation and AI technology may develop and what that will mean for the future of the industry. Some recent practices that have severely impacted the job market lately have been globalization (where work moves overseas) and automation (where machines replace human labor). Globalization is not a major threat to our industry due to the local nature of our jobs. However, automation seems like a more valid concern. Automation has been occurring for a long time; it started off by replacing animal labor with vehicles at the beginning of the Industrial Revolution in the 1800s. Machines have also slowly been replacing repetitive human tasks. Some high-wage professions have already been replaced by technology, including tax preparers and travel agents. That is because those people make high wages, and automation makes sense economically. Conversely, the cost to replace a fry cook with a robot would probably exceed the amount of money it would save in wages. However, humans use their senses to solve problems; machines cannot make judgments based on sight, smell, sound, etc. HVAC techs use those senses to diagnose issues with the system. So, HVAC techs would be very difficult to replace with robotic technology. The customer service element of HVAC work, especially listening skills, would also be difficult to reproduce in a robot. So, we have lots of assets that technology cannot replace anytime soon. Bryan and Adolfo also discuss: Maintenance vs. healing Datasets, algorithms, and robots Technicians that will be automated before HVAC techs Variable vs. standardized technology (homes vs. cars) The concern of "dumbing down" techs with smarter diagnostic equipment   If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In this episode of the podcast, Jeremy Arling from the EPA comes on and answers some common questions about the new rule changes that affect recovery, leak repair, recordkeeping, and evacuation on HVAC and refrigeration systems. EPA 608 rules regulate the actions that technicians must take when it comes to refrigerants and the atmosphere, such as venting, recovery, and evacuation. It has always been illegal to vent HFCs, including R-410A. The changes to EPA 608 attempt to treat all refrigerants equally; R-410A would be on equal footing with HCFC R-22, for example. EPA 608 also clarifies the actions that require certification, including the purchase of ozone-depleting substances. It is not illegal to recharge CFC or HCFC refrigerants. However, the availability of HCFC refrigerants will dwindle over time; systems will need to be charged with reclaimed refrigerants, not new R-22. EPA 608 will also crack down on recordkeeping for recovery and reclamation. The technician does NOT have to keep the records; it is the responsibility of the company. However, the technician should keep track of the recoveries they do and provide those records to their companies. When recharging leaking systems with over 50 lbs of refrigerant, technicians should know that HCFC-reliant appliances must be repaired, retrofitted, or retired within specific timeframes. There is no minimum time frame between the leak repair and verification testing; however, the EPA recommends testing within 10 days of the repair. The EPA has approved the use and recovery of flammable refrigerants for a handful of industrial applications. Most of these also receive exemptions from the venting prohibition. Resources You can find the complete rule update HERE. You can also find Jeremy's presentation slides HERE and a quick sheet for technicians HERE. If you want an app to help you keep a record of recovered refrigerant, I would suggest looking at the R-Log app HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In this episode of the podcast, Jim reviews the basics of evacuation and dehydration. He also covers hoses and vacuum gauge placement. Evacuation may just seem like a method to suck air and water out of a system. However, it is an intricate science that lacks a lot of detail in most trades education programs. The deepest vacuum we can possibly pull merely offsets the atmospheric pressure and is actually not that deep; the deepest possible vacuum is -14.7 PSI (-29.92" Hg). The evacuation rig is the most important element of evacuation. If you want a fast evacuation, DO NOT use 1/4" hoses or manifolds. However, those are both common practices in the HVAC industry. The only way to increase the flow of refrigerant, air, and water out of a system is to increase the hose diameter. Larger hoses have less resistance than smaller hoses. Pump size does not seriously impact evacuation speed when compared to hose diameter and the presence/absence of Schrader cores. Schrader cores are other major sources of restriction, and you'll want to use core removal tools. Air from a vacuum pulls in a localized area. As such, it is a BAD idea to hook your vacuum gauge up at the vacuum pump. You are measuring the pressure of the pump, in that case, NOT the whole system. When you read 500 microns at the pump, the real pressure of the system could be over 1000 microns (especially if you have 1/4" hoses). Bryan and Jim also discuss: Atmospheric pressure Connectors What is a "good" vacuum? Decay tests Moisture throughout the system and its effects on decay Water's state changes and vacuum Sublimation and ice during an evacuation Capping off, soldering, brazing   If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In this episode of the podcast, Jamie Kitchen from Danfoss talks about wet-bulb, dry-bulb, relative humidity, dew point, enthalpy, and latent heat. These are the building blocks of psychrometrics, which deals with human comfort as it relates to temperature, humidity, and heat loads. Humidity is water vapor in the air. As the air's dry-bulb temperature increases, the more water vapor the air can hold. That is partially why dew is more common on cold mornings instead of hot ones. However, the air's weight does NOT increase with more water vapor; moist air is less dense than dry air. Moist air has more heat energy than dry air, though. Relative humidity (RH) is the percentage of moisture that the air can hold before saturation. Saturation occurs at 100% RH. In psychrometrics, there are two different types of relevant temperatures: dry-bulb and wet-bulb. Dry-bulb temperature refers to true thermodynamic temperature; humidity doesn't affect the reading. Wet-bulb also accounts for the rate of evaporation in the air; it accounts for the body's ability to cool itself through evaporated sweat. When the wet-bulb and dry-bulb temperatures are nearly identical, that means that the RH is high. We have psychrometrics charts, and we can plot points based on wet-bulb and dry-bulb temperatures. These charts also have a "dew point" on them, which is the point where the air can no longer hold more grains of moisture. That moisture then condenses into dew or fog; this point is saturation or 100% RH. Dry-bulb and wet-bulb temperatures will be the same at the dew point. Bryan and Jamie also discuss: Absolute moisture content (moisture grains) What Willis Carrier understood Evaporative or adiabatic cooling TXVs vs. fixed-orifice metering devices and temperature Sensible vs. latent cooling Commissioning equipment for comfort   If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In this episode, Bryan and Jim discuss measuring voltage drop and what it means. They also cover some other pointers to keep from using parts to bandage a deeper issue. A common mistake that technicians make is not understanding what an ideal measurement is before making a measurement. For example, they may not know what the refrigerant pressures should be before they attach the gauges. Electrical measurements are the same, and voltage drop falls under that umbrella. Voltage refers to electrical pressure, and current refers to electrical flow; they are two different values. The voltage will typically be at its full value (e.g., 240v) until you test the system under load. The voltage will drop when the motor begins turning. A motor will generate either motion or heat. When a motor doesn't have enough electrical pressure (voltage) to start, it will generate heat until it trips an internal overload. Upon startup, a standard voltage drop will be around 20% on a properly sized circuit. When the unit drops voltage in excess, the compressor turns more slowly and reduces its output. Many technicians measure voltage to see if it merely exists. They do not attempt to see if the voltage is at an appropriate level, and that's a major pitfall in our industry. Technicians ought to know the appropriate voltage values so that they can assess if the voltage drops are normal or excessive upon startup and while a compressor is running. Common issues that cause excessive voltage drop include: Excessive heat loads in the building (from other electrical appliances) Undersized feed wires from the transformer to the pole Loose lugs Corroded connections Conductors that are too small or too long   Before bringing out the hard start kit, make sure you do all of the preliminary checks to make sure you REALLY need it. Make sure the feed wire is the correct size and that your connections are solid. A hard start kit will mask the issues of voltage drop for a short time, but they don't address the core issue. So, just check voltage drop under load. Voltage drop should not exceed 20% on startup and 3% while running.   If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.