HVAC School - For Techs, By Techs

In this short podcast episode, Bryan compares strategies for increasing the subcooling, including stacking liquid and mechanical subcooling. Subcooling is a consequence of condensing; when we change the refrigerant from a vapor to a liquid, it will drop below saturation temperature after it becomes completely liquid. There are three phases in the condenser: desuperheating, condensing, and subcooli...

In this podcast episode, Bryan, Chad, John, and Allison discuss proper design for ductless and ducted HVAC systems, especially mini-splits. They also discuss potential future improvements to equipment and duct designs. Mini-splits are smaller than traditional HVAC units, so they make zoning a bit easier. However, load calculation plays a huge role in equipment selection and zoning because you must...

In this short podcast episode, Bryan explains what atmospheric pressure really is, pressure units and conversions, and why those are matter. Atmospheric pressure is the weight of the air around us pushing down on us. We normally see that value expressed as 14.7 PSI (or 0 PSIG). Before we dive too deep into atmospheric pressure, we should understand some basic pressure units. We may see pressure ex...

In this podcast episode, Bryan and Trevor Matthews discuss compressor short cycling. They discuss how to diagnose and prevent that issue. Trevor and Bryan primarily refer to the Bulletin AE17-1262 throughout this episode, which you can find HERE . Compressor misdiagnosis is very common, but we generally encounter two types of compressor failures: electrical failures and lubrication failures. Short...

In this podcast episode, Bryan and Craig Migliaccio (AC Service Tech) discuss some HVACR recovery tips and best practices. When you select a recovery tank, you need to know which refrigerant is in the tank. So, it's a good idea to make sure you label each recovery cylinder. You don't want to contaminate refrigerant in the recovery tank, use a recovery tank with contaminated refrigerant, or have to...

In this episode, Bryan and Craig Migliaccio (AC Service Tech) talk about some best practices you can use while swaging and flaring copper. There are a few different ways you can flare copper. Craig likes using a round deburring tool before flaring the copper. After the burr has been cleanly removed, Craig likes using an eccentric flaring tool for the actual flaring. Bryan's favorite flaring tool i...

In this podcast episode, Bryan and Jim Fultz discuss the White-Rodgers SureSwitch and determine whether contactors are obsolete or not. Contactors are electrical controls; they started off very expensive and usually outlasted equipment, so they are currently smaller, cheaper, and less durable than they used to be. Modern contactors have open contacts and are susceptible to insect damage. Sometimes...

In this episode, Bryan and Craig Migliaccio (AC Service Tech) discuss all the ways that nitrogen can make your job easier. Nitrogen is an inert gas that we can use for purging refrigerant lines and completing scale-free brazing jobs. As techs, we should have at least one inert gas in our trucks to help us do the best job possible. We can use inert gases for purging refrigerant from tubing, flowing...

In this podcast episode, Bryan and Craig Migliaccio, AC Service Tech, talk about ultrasonic leak detection. They discuss its effectiveness and if it's worth the hype. Ultrasonic leak detection works best when there's oil on the inside of the tubing; it works best when the system is equalizing after shutoff. Oil or moisture can create a squealing noise, which is an indicator of a leak. Ultimately,...

In this podcast episode, Jim Fultz with White-Rodgers joins us to discuss universal defrost controls. He also explains when and why you might use universal controls. Bryan and Jim cover a universal defrost control for heat pumps (Model #: 47D01U-843). You can follow along by reading the manual HERE . Universal defrost controls can replace OEM defrost controls. Universal controls are sometimes more...

In this short podcast episode, Bryan and Craig Migliaccio discuss why you maybe don't want to buy new tools. Whenever you get new tools, you have to account for a learning curve and potential change to your practices. Changing your practices and procedures isn't necessarily a bad thing, but you have to practice with the tool and account for different setup and cleanup procedures. However, once you...

In this podcast episode, we find out how Craig Migliaccio became "AC Service Tech." He makes educational materials and has even written a book. You can check out his website HERE and his YouTube channel, AC Service Tech, HERE . Craig got into the HVAC trade after coming from a construction background; he mostly worked on existing homes and had to handle some HVAC tasks. From there, he got into ser...

In this short podcast episode, Bryan and Craig Migliaccio discuss the skills and knowledge you should have to start in the HVAC industry. Of course, basic mechanical skills and knowledge are important before you get into the HVAC trade. You'll greatly benefit from knowing where and how to hammer nails, tighten screws, and identify all sorts of tools. When getting into the HVAC industry, one of the...

In this podcast episode, Bryan and Trevor Matthews of Emerson Canada discuss strategies for controlling liquid refrigerant in A/C and refrigeration systems. They also read through the AE22-1182 bulletin, which you can find HERE . Liquid refrigerant is one of the most common causes of compressor damage and even failure. It can also cause a loss of oil, which leads to reduced lubrication and subsequ...

In this short podcast episode, Bryan talks about the TXV power element or power head. He explains what it does and why it's important. A TXV power element threads onto the top of the valve, and it's where the sensing bulb attaches to the valve. It is the component that applies the opening force to the TXV. When you lose the charge in the element, it stops exerting an opening force on the valve. So...

In this episode, Bryan and Alex Meaney talk about value engineering. They discuss what it means to value engineer better when it comes to construction projects. Value engineering is about finding ways to reduce the costs of a project. However, we don't want to do a bad job or use extremely cheap materials just to bring the price tag down. In many cases, builders will want to reduce the cost as muc...

In this short podcast episode, Bryan talks about the placement of the TXV sensing bulb. He also explains how it affects the opening force on the TXV. The TXV sensing bulb (or sensor on an EEV) provides the opening force for the valve. The warmer the bulb gets, the more the valve opens; the colder the bulb gets, the more the valve closes. The TXV also has a closing force provided by the spring pres...

In this podcast episode, Bryan, Erich Vinson, and Anthony Marino talk about dealing with difficult customers in the HVAC industry. When working with customers in general, it is best to make eye contact with the customer, listen to them, and put yourself in their shoes. When dealing with difficult customers, we must remember that there are several potential causes for their "difficulty." You can't...

In this short podcast episode, Bryan explains how hydrostatic pressure can build up in refrigerant cylinders and present a hazard to technicians. Your refrigerant cylinders have tare weight and water capacity values stamped on the tank. You'll want to use these when weighing the refrigerant you recover because you don't want to exceed 80% capacity. However, capacity changes when the liquid density...

In this podcast episode, Bryan, Trevor Matthews, and Jim Dick from Emerson give us all an introduction to industrial refrigeration. Jim works with contractors to provide tech support. He also does the startup and commissioning of refrigeration compressors and gas compression units. Industrial refrigeration refers to warehouses and distribution networks. Grocery refrigeration is commercial refriger...

In this short podcast episode, Bryan talks about the strategies we can use to prevent refrigerant migration during the off cycle. We often see refrigerant migration when the compressor is lower than the evaporator, especially in low-ambient conditions when the refrigerant can condense in the crankcase. When the compressor starts up, you get a violent reaction as the refrigerant boils off and eject...

In this podcast episode, Eric Mele joins Bryan for some weird transformer talk. They discuss corner-tapped transformers and some thought experiments. We hadn't been able to get our heads around corner-grounded transformers until recently. "Grounding" doesn't necessarily change the phase or lead that you ground. If you take the secondary of a 24-volt transformer and measure from your two colors, yo...

In this short podcast episode, Bryan compares internal and externally equalized valves. He also covers how forces act upon the TXV. Equalization does not happen on the off cycle. When we talk about equalization, we are merely talking about a force that balances against the bulb force. A TXV sets the superheat within an operating range at the evaporator outlet; the sensing bulb on the TXV detects t...

In this podcast episode, Bryan talks with Bill Spohn about his most recent project, SpohnHome. SpohnHome explores Bill's journey in custom home performance. Projects are complicated because so many trades work together to accomplish a building. However, custom homes are particularly challenging, especially in Bill Spohn's case. His home is a "personalized performance home," so he's prioritizing en...