HVAC School - For Techs, By Techs

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.

In this podcast, Jeff Neiman shares an overview of his chiller startup procedure and some things he looks out for when starting a chiller after the initial chiller installation. The actual chiller startup is typically the factory's responsibility (per the manufacturer); however, the "startup" that we're talking about refers to the installation and early maintenance. The first step is preparation. Neiman recommends having a copy of the installation manual and reading it beforehand. You should also have a "request for startup" or pre-commission checklist. You also want to make sure there is water in the system before starting up a chiller. Technical datasheets are also useful to have on hand. Once you get to the job site, inspection will be your main job. You can look for dents in the coils and other signs of damage from shipping or mishandling. Review the installation location. Make sure there is proper clearance around the chiller. As with other HVAC units, liquid in the compressor is catastrophic. So, make sure that the screw compressor is warm and liquid-free. Although centrifugal chillers have separate oil systems, heat is also important in those chillers because it warms the bearings. Next, you can open up the panel and check the power. Perform a voltage imbalance calculation to make sure your voltage is satisfactory. Check for proper wire sizing and the number of conductors. Check that the piping has been done properly for the flow direction. The condenser fan has set screws, and it would be wise to verify their tightness. Then, you check your water flow to make sure it fits all the correct parameters on your technical datasheets. Check the valves, flow, and pressures as specified. 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 James Bowman from Rectorseal about hard start kits, PTCR devices, run capacitors, compressor overheating, and the Kick Start product. We also go pretty in-depth on potential relays and how they operate. Hard start kits are mechanical potential relays connected to a capacitor, and they aid in starting the compressor. They come in two-wire and three-wire types. However, they have some pitfalls. For example, they are easy to abuse. You may also come across a "hard start kit" that does not have a mechanical potential relay (such as a PTCR), which is not a true hard start. Many of those false kits are low-quality and borderline dangerous. The start cycle starts in approximately 0.4 seconds. A proper hard start kit will help the compressor start in less than 0.4 seconds. Two-wire electronic start kits don't react quickly enough and cannot remove themselves from the circuit in time. Two-wire mechanical potential relay kits, on the other hand, measure voltage between run and start, unlike a three-wire device that measures the voltage between common and start. Three-wire devices are typically okay, but they are not a universal component that can fit every unit. Rectorseal's Kick Start kit is an aftermarket kit designed to work on most units as a replacement for the OEM kit. When dealing with aftermarket hard start kits, the best practice is to know your equipment and the hard start kit's compatibility with the unit. Hard start kits work especially well with reciprocating compressors with long line sets and HVAC systems with hard shutoff TXVs. Bryan and James also discuss: Potential relays Back EMF Start capacitors Testing run capacitors under load and with meters Looking at systems holistically Copper plating inside compressors For more information, go to rectorseal.com. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

In part 2 of this conversation, we go through the condensing unit and wrap up the call with our no-fluff customer service best practices. The service call A thorough inspection is critical on any residential service call. A service call is an opportunity to check the integrity of the unit and the cleanliness of the blower wheel, drain, and other components. Check the charge, safeties, and five pillars. List the problems and present the solutions as suggestions. Provide appropriate timetables and provide all necessary information. If possible, you can let the customer watch you work on their system to build that trust and teach them about the unit. If the customer gets worked up over the pricing or frustrated over something with their unit, own the frustrating circumstance. Make sure you stay calm and rational with them. Remember, you are a consultant that they should trust, and it is best to be empathetic and professional at all times. When exiting the call, try to move on without spending too much time chit-chatting with the customer. Offer to answer questions by giving your contact information or the office's contact information.

This is part 1 of 2 on the soft skills practices of approaching and completing a residential service call in the best manner possible. Before the service call and good housekeeping Before a technician even leaves to go to work, they need to get their head in the game. Be ready to face the day by showering, shaving, and brushing your teeth. Having self-respect is also a sign of respect for the customer. The drive to work is a good place to clear your mind; you can listen to podcasts or do other things to get yourself in a good place to work effectively. Getting to work early is also a good practice. At the beginning of the workday, you can get a coffee, restock your truck, and fuel your truck to start your day with everything you need. When going to a customer's home, make sure you have reviewed the history of the unit and get there on time. Exit your truck as soon as possible; customers expect prompt service. Introduce yourself politely and listen to what the customer says. Respect their home; don't leave your trash on their property, don't smoke, and be careful not to let the smell of cigarettes bother the customer.

In this podcast episode, Bryan talks about grounding and some common misunderstandings related to ground, neutral, ground rods, and lightning. The common phrase that "current goes to ground" is a myth. The transformer (or the power source) that feeds a building creates a potential difference in charges (voltage); current is the motion of electrons between a difference in charges. A transformer has three terminals: two legs and the XO terminal (neutral). You have 240 volts between legs and 120 between each leg and the XO terminal. The leg of power going into the transformer is split into two in a single-phase application, so the sine waves are completely out of phase with each other. When you connect to a transformer, all of the power is either a balance between the two legs or is between the legs and the XO terminal (neutral); it NEVER goes to ground. If any power is traveling to "ground," it is traveling to the ground and going back to the source because there is no other path. Power travels to the ground and then to the source when neutral isn't properly bonded to ground. Another common myth is that the current always takes the path of least resistance. The current does not always take the path of least resistance; it may take all appropriate paths. All equipment is grounded to create a ground fault (this is called "grounding"). Then, it should be connected to a ground rod. Grounded assemblies attempt to dissipate high-voltage occurrences, such as lightning strikes and massive surges from distribution lines. Lightning is a very high-voltage DC phenomenon that can be fatal to people or equipment. So, dissipating electromagnetic pulses to ground is much safer. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Bryan talks with Nick Messick about some ice machine basics. They also discuss how to determine when to pick up the phone and call tech support. Ice machines have the same basic refrigeration circuit as HVAC systems. However, ice machines require a much different cleaning regimen. Many maintenance people neglect ice machines by using incorrect cleaners. You need more of a sanitizer than a cleaner; sanitizers kill germs and fungi, but cleaners work better on corrosion. When cleaning an ice machine, watch out for mold and scale buildup. Scale buildup is especially problematic because it hardens the water. You can use ice thickness probes or listening devices to determine the condition of the water (and ice). Also, use a nickel-safe cleaner, like Refrigeration Technologies' Viper Nickel Safe. Ice machines have "harvest cycles" where ice collects. Ice falls off the evaporator when warmth hits the evaporator. An ice machine may use hot gas or "Kool gas" defrost. Hot gas defrost reverses refrigerant through the cycle and sends discharge gas to the evaporator. Manitowoc systems use Kool gas, which uses saturated vapor at the top of the receiver and results in a quieter harvest. Tech support can really help you if you can't understand the manual or get stuck. However, some techs let their pride prevent them from calling tech support. Ultimately, calling tech support to help you understand an ice machine will save you time and save the customer money. You can also walk away from a situation having learned something new for next time if you call tech support and let them help you. However, calling tech support should NOT be a crutch that techs depend on all the time; basically, don't let them be your autopilot. 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 condenser wire sizing considerations, ampacity, temperature, conductor sizing, voltage drop, and why a #10 wire doesn't always require a 30-amp breaker. There's usually nothing wrong with OVERSIZING a wire or conductor. However, you still need to know which wires are safe for operation and comply with the National Electrical Code (NEC) protocols. Relatively small conductors can carry relatively high voltages. Instead, amperage dictates the size of the wire. Therefore, we use ampacity (amp capacity) to determine the size of a wire. Transformers are a perfect example; wires going into the transformer are small, and wires leading out of the transformer are larger. You also size circuit breakers, fuses, or overcurrent protectors to protect the conductor. The wire type that goes into a breaker depends on several variables. Some of these variables that affect ampacity include wire material, insulation rating, ambient temperature, and how many other conductors are in the same metal area. Thus, rules of thumb for wire sizing are not reliable. If the ambient temperature exceeds a wire's rating, you can derate a wire by using a multiplier; use the values in Table 310.15(B)2(a). A major concern for wire sizing is the probability of a short circuit. The term "short circuit" is often misused to describe ANY sort of electrical failure, but that is not the case at all. "Overcurrent" or "ground fault" is a more precise term for excessive amperage. Overload conditions indicate that the load is too large, so high amperage is drawn. Compressors draw the highest amperage out of all HVAC system components. Overall, size your conductor by minimum circuit ampacity and your breaker based on maximum overcurrent protector 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 to Bill Spohn from TruTech Tools about how TruTech Tools got its start and some of the ways that techs and engineers approach problems differently. Bill Spohn is a majority owner of TruTech Tools who became invested in the HVAC field in the 1990s. The beginning of TruTech Tools was a milestone in Bill's professional journey. After working at Superior Valve for a few years, Bill moved to Testo. While Americanizing many of Testo's products, Bill Spohn met Jim Bergmann. A German Testo employee advised Jim Bergmann's father to set up an online store for the Testo products and other HVAC tools. That website later became known as TruTech Tools. Jim, his father, and Bill were at the forefront of the new company. Bill contributed to the development of TruTech Tools through his product and marketing knowledge. Since then, TruTech Tools has grown a lot more. Jim Bergmann has since moved on, but he is still friends with Bill and remains a major figure in the instrument development and testing part of the HVAC industry. Bill considers himself to be an engineer. Unlike technicians, engineers have a deeper level of expertise in the development of tools and products. However, technicians have greater field knowledge and provide valuable feedback for engineers like Bill. Engineers know the math behind their products and how to use those products. However, technicians provide the practical element to tool development. Both technicians and engineers must be humble to work well together, exchange ideas, and technologically progress. You can always get a great discount from Trutechtools.com by using the offer code getschooled at checkout. Check out our handy calculators HERE.

In This episode Justin talks about the trials and benefits of working out of town, long drives and this weeks boiler service calls in detail.

Jesse and I talk about MORE best practices for installing ductless systems. Both lines should be insulated on a ductless system because they have electric expansion valves in the outdoor unit. Insulating flares is also a critical task. When it comes to flare fittings, overconfidence is a tech's biggest enemy. Techs often undervalue the process of reaming copper or overdo it. Bubble-testing the flare joints is always a best practice to evaluate the integrity of your flares and check for leaks. Do not braze copper on ductless systems! Ductless evacuations require deep vacuums. Removing cores and valving off are best practices for evacuation; the goal is to reduce the risk of contamination, just like normal split systems.

Bryan and Jesse talk in detail about ductless applications we commonly see, best system placement, drains, and much more. Ductless systems are unique, and their compact nature makes them a good choice for several small, controlled applications. These applications are in climate-controlled garages, lanais (sunrooms), and master bedrooms. In Florida, lanais are the primary application for ductless units, especially due to codes that regulate HVAC systems in lanais. When installing a ductless unit, Jesse looks for aesthetics and reliability. Since ductless units are visible, making them look good inside the home is a concern that you don't typically worry about on split systems. When it comes to the drain line, Jesse likes using gravity drains on exterior walls. Many callbacks deal with drainage issues, so drains can reduce ductless units' reliability. Condensate pumps also occasionally have issues, so Jesse puts the pump in a way where all connection points are below the ceiling to avoid ceiling damage. However, float switches and overflow devices may also be required by code and may help.

In this episode with BENOÎT MONGEAU, we talk about the components of combustion and what to consider when testing it on a fuel-burning appliance. Combustion requires fuel, oxygen, and a heat source in a correct balance. We call that series of requirements the "combustion triangle." Once combustion occurs, it is self-sustaining. However, removing one element of the triangle will end combustion. (For example, you could suffocate a flame by removing the oxygen content.) Undesirable consequences of incomplete combustion include the production of carbon monoxide, a potentially fatal gas. Flash point is the temperature at which vapors can ignite. Excess air is the air that you're inputting into flue gas that doesn't get used for burning. It contains nitrogen and oxygen and doesn't contribute to the burning. However, it does expand the volume of the flue gas and absorbs heat. Excess air indicates a loss of efficiency and colder gas. (Note: Perfect efficiency is theoretically possible but impractical.) High-efficiency furnaces have longer run times, which may confuse customers; customers may think that the longer run times mean that there is something wrong with their heating system. Natural gas is mostly methane, so it is easy to burn with the right amount of oxygen. Propane (liquid petroleum) is a larger molecule with three carbons. Propane requires more time and more mixing for proper burning. The larger the molecule, the more time you have to spend waiting for combustion, and it's harder to burn the molecule completely and properly. Benoit uses Testo combustion analyzers and TPI digital manometers when working with furnaces. He uses heat-rise calculations whenever he wants to calculate CFM on a furnace. CFM tables are in the manufacturer's manual. As always, if you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.