HVAC School - For Techs, By Techs

In this candid team meeting, Bryan — a founder of Kalos Services and a veteran of residential HVAC — gathers his install crew to have an honest conversation about what goes wrong on the job. With summer around the corner and the workload about to spike, Bryan circles back to his roots in residential HVAC to lead a round-table discussion on the pain points his technicians face every single day. Rather than pointing fingers, he opens the floor for every team member to voice the specific frustrations that slow down their installs, and what emerges is a surprisingly consistent list: size and clearance problems, missing small materials, incomplete job photos, and last-minute schedule changes that leave crews scrambling before they even pull out of the shop.

Bryan draws on his own humble origins as a one-man operation hauling equipment on a Gladiator trailer — doing installs, service calls, and waste runs all in the same day — to remind his team that chaos is not inevitable; it is the byproduct of poor process. He is refreshingly self-aware, admitting that he was a very bad installer who routinely showed up with equipment that did not fit the space. That honesty sets the tone for the entire session: this is not a lecture about accountability, but a collaborative problem-solving conversation about building repeatable systems that prevent the same mistakes from happening over and over again. As Bryan frames it, the definition of insanity is doing the same thing and expecting a different result — and right now, the team is living that cycle.

The heart of the session focuses on a three-phase planning framework: what should be done the night before a job, what should happen at the shop before the crew leaves, and what needs to occur during the first 30 minutes on-site. Bryan emphasizes that skipping proper measurements and job photos should carry the same weight as failing an inspection or leaving a refrigerant leak — because the downstream cost is just as real. He breaks down the two categories of mistakes that are truly unacceptable for any installer: refrigerant leaks from improper brazing, and water leaks from poorly executed drain lines. No amount of clean workmanship makes up for either of those failures, and he walks the crew through the non-negotiable steps — pressure testing and bubble solution on every single joint — that prevent them.

Bryan wraps up by tying individual preparation habits to the bigger picture of company growth. He acknowledges that last-minute installs and mid-job equipment runs may never fully disappear, but that investing 15 minutes the evening before and 30 minutes on arrival creates a compounding tipping point effect — over time, the crew gains back hours, reduces surprises, and frees up the time that matters most: commissioning the system properly. Checklists, he argues, are not about turning skilled tradespeople into robots; they are about transferring institutional knowledge to the next generation of technicians and ensuring that nothing critical gets overlooked, no matter how many times you have done the job before.

Topics Covered

• Common install-day problems surfaced in a round-table with the install crew
• Equipment size and clearance issues — why measurements matter before the truck leaves the shop
• The critical role of detailed job photos in preventing on-site surprises
• Missing small materials (wire nuts, spray foam, surge protectors, breakers) and how to stock proactively
• Scope and de-scope review: aligning the proposal with the homeowner before work begins
• Bryan's three-phase planning framework: the night before, at the shop, and on arrival
• Why refrigerant leaks and drain-line failures are the two non-negotiable mistakes to eliminate
• Pressure testing and bubble solution as a standard, every-joint practice
• The role of checklists in training new technicians and preserving institutional knowledge
• Handling last-minute installs and the logistics of getting equipment to the job site
• Condenser access obstacles — bushes, parking, property layout — and how to communicate with homeowners
• Faulty or missing parts out of the box and strategies for catching them early
• Panel rework and surprise platform rebuilds: planning for the unexpected
• How improved preparation leads to better commissioning time at the end of every job
• Building a culture of process over blame — poor planning is a system problem, not a people problem

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

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In this short podcast from the Bry-X stage of the 7th Annual HVAC/R Training Symposium, Ty Branaman and Leilani Orr talk about how to teach kids the trades. They share lessons they've learned from the GRIT Foundation and over their careers as trades and home educators. Their approaches have evolved over the years, and GRIT has also evolved quite a bit from its beginnings.

Leilani and Ty have found that the Socratic method is great for getting students to think critically; instead of spoon-feeding answers, teachers ask the students "why" and "how" questions. In GRIT Camps, mentors are there to keep students safe and guide them when needed, but mentors ultimately let students make mistakes and figure things out on their own. Students often make leaky joints when they braze for the first time, but it's their first time holding torches and most of the tools used at GRIT Camp.

Making mistakes is crucial to the learning process. The mistakes we (and the students) make with our own hands also stick with us more than being told how to do a task the right way. Then, when students struggle, we can ask if they want to know a shortcut; they give their mentors permission to show them the right way. This method builds curiosity, and it allows students to get excited about a career in the trades or realize that the trades aren't for them but still walk away with hands-on skills and a newfound respect for the trades.

Many tradespeople take the trade skills they learned as children for granted, as many children nowadays don't develop the same hands-on skills. The GRIT Foundation has a course that teaches mentors to teach students those hands-on skills that already seem like second nature to them. Even so, the course is just a guide, not something that needs to be followed to the letter. Many of the concepts taught in the guide and that mentors use at GRIT Camp also apply to apprentices.

Learn more about the GRIT Foundation at https://www.thegritfoundation.com/.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

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In this episode, Brad Cooper — second-generation HVAC technician, educator at Arkansas State University-Beebe (ASUBB), and CMHE-certified professional with HVAC Excellence — breaks down geothermal systems for everyday HVAC technicians. Brad brings a grounded, no-hype perspective to a technology that has long intimidated many in the trade. His central message is simple: if you already understand heat pumps and air conditioning, you already have most of the knowledge you need to service geothermal units. The only real difference, as Brad explains, is swapping air for water, a fan for a pump, and a condenser for two heat exchangers.

Brad opens with a compelling real-world story: a customer with two malfunctioning geothermal units called a company for help, but because the technicians were unfamiliar with geothermal systems, they replaced both units with air-to-air equipment — costing the customer $25,000 and stripping them of the significant efficiency benefits geothermal provides. This kind of outcome is exactly what Brad wants to prevent. He urges technicians not to shy away from geothermal work the way past generations were told to avoid flex duct or mobile homes, but instead to approach these systems with the same confidence and diagnostic mindset they bring to any HVAC call.

A major portion of the episode is devoted to practical diagnostics — specifically, how to use a pressure probe and a temperature probe on the water side to calculate GPM flow, BTU output, and system efficiency using a straightforward chart. Brad walks listeners through the math: a gallon of water weighs 8.34 pounds, multiplied by flow rate and delta T, gives you a reliable BTU reading — all without expensive equipment. He also covers the flush cart, the one specialized tool you'll eventually need for water-side work, and explains that most geothermal calls don't require it at all — the majority of failures are standard heat pump issues like bad capacitors, clogged drain lines, or faulty thermostats.

Brad closes with an encouraging, community-minded message: you don't need to go it alone. He encourages technicians to build a network of mentors — someone like a "Paul and a Barnabas" — who can guide them through unfamiliar territory in the field. He also highlights key industry resources, including IGSHPA (International Ground Source Heat Pump Association) for training and certification, GeoFlow for parts and materials, and his brother's company, EDGE Geo Supply, for tools and field training. Brad himself offers his personal phone number and email for anyone with questions, reinforcing that the geothermal community is accessible and willing to help.

Topics Covered

• Brad's background as a second-generation HVAC tech and his role at ASUBB and HVAC School

• Why geothermal systems intimidate technicians — and why they shouldn't

• The core analogy: air-to-air vs. geothermal (air → water, fan → pump, condenser → two heat exchangers)

• A $25,000 cautionary tale: replacing working geo units out of fear and unfamiliarity

• Geothermal efficiency: constant EER ratings vs. seasonal SEER ratings and why seasons don't affect geo performance

• BTU fundamentals: what a BTU is and how to calculate BTU output on the water side

• Tonnage review: 1 ton = 12,000 BTUs per hour, melting a ton of ice in 24 hours

• Water weight and flow math: 8.34 lbs/gallon, calculating GPM and BTUs with delta T

• Using a two-probe setup (pressure + temperature) and a field chart to diagnose water-side performance

• The flush cart: what it is, when you need it, and why most jobs won't require it

• Common heat pump-side failures in geo units: capacitors, low-pressure switches, evaporator coils, bad thermostats

• Common water-side failures: bad pump, low water, dirty water, frozen loop field

• How antifreeze/glycol affects heating load and BTU output — and when to add it

• Responding to frozen loop fields during extreme cold events (ice storms in Arkansas and Texas)

• Humidity control advantages of geothermal in high-humidity climates vs. high-efficiency air-to-air units

• Selecting the right system: geo isn't for every home or every situation

• Open-loop options: pulling water from lakes or rivers and utility company incentives

• Closed-loop installation considerations: drilling costs, lot size, and buried line depths

• Building a mentor network for field support (the "Paul and Barnabas" principle)

• Industry resources: IGSHPA for training and certification, GeoFlow, and Edge Geo Supply

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

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In this short podcast, Ruchir Shah and Dan Riggs from SkillCat talk about how to make online training that does not suck! They talk about how to develop training that is relevant to the trades and can be applied in real-world trade work.

The skill gap is widening in the trades, especially as shortages grow when people retire and it becomes more difficult to hire qualified new people. Hiring apprentices with little experience also has costs associated with it, and SkillCat aims to address the training reasons for the skill gap and provide the needed accreditation for trades like HVAC (including EPA 608). After receiving feedback that the curriculum was too theoretical and could do better in the applied learning areas, the SkillCat team has been revamping the training program with a skill map.

Now, there are partnerships with trade educators, more interactive videos, and interactive virtual activities to create a more relevant learning experience. There are now kits that SkillCat ships out to trainees, and assignments have offline proctors who verify all submitted materials and online activities to ensure that the trainees' submissions align with real field conditions and expectations. The goal is to have trainees who enter the field and can be fully functional helpers with a basic tool kit and enough working field knowledge to identify system components and perform basic tasks, bringing value to employers from day one. SkillCat is going to be piloting a new training program with a mentorship component as well.

Learn more about SkillCat at https://www.skillcatapp.com/ and the GRIT Foundation at https://www.thegritfoundation.com/.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

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In this action-packed live stream episode of HVAC School, host Bryan is joined by Eric Kaiser, Ty Branaman, and Roman Baugh for a continuation of a deep-dive conversation on vacuum practices — picking up where a previous episode left off with Andrew Greaves and Jim Bergmann. The team sets out to both reinforce the foundational best practices every HVAC technician should follow and to explore some genuinely uncharted scientific territory around how vacuum gauges actually work, how refrigerant contaminates micron gauge readings, and what really happens to moisture inside a system when temperatures drop below freezing.

A central revelation of the episode is Eric's explanation that modern electronic vacuum (micron) gauges do not actually measure pressure directly — they measure heat transfer and translate it into a pressure reading. Because these gauges are calibrated to nitrogen or air, the presence of refrigerant vapor in a system (which has roughly three times the heat conductivity of nitrogen) can cause the gauge to display a falsely high reading. This means a technician could believe the system still has poor vacuum when it may actually be further along than indicated — or, more concerning, that a system appears to have passed vacuum when contamination is still present. The team acknowledges that controlled experiments are needed to quantify exactly how much refrigerant affects the reading, and they commit to designing those tests.

The conversation then pivots into the physics of water at the triple point — the precise pressure (4,580 microns) and temperature (32°F) at which water can exist simultaneously as solid, liquid, and vapor. Eric walks the audience through a phase diagram built from International Association for the Properties of Water and Steam data, explaining that once pressure drops below the triple point, liquid water no longer exists. Any moisture in the system either sublimes directly from solid ice to vapor or remains frozen. This has major practical implications: a system with ice inside can still pull down to a very deep vacuum, but will not pass a decay test until that ice is fully sublimated — which requires both sufficient vacuum depth and available heat energy. The colder the ambient environment, the deeper the vacuum must go to create the temperature differential needed to drive sublimation.

The episode wraps with an illuminating discussion on refrigerant oils — specifically the differences between POE (polyolester) and PVE (polyvinyl ether) oils and how each interacts with moisture in fundamentally different ways. POE chemically bonds with water through hydrolysis, breaking down into acid and alcohol and permanently degrading the oil. PVE, on the other hand, physically traps moisture through surface tension and can hold up to twice as much water as POE, but remains chemically stable. This distinction affects vacuum strategy, dryer sizing, and long-term system reliability — particularly in VRF and cold-climate heat pump systems where compressor oil management is far more complex.

Topics Covered

• Core vacuum best practices refresher: large hoses, removing valve cores, skipping the manifold, using clean pump oil, micron gauge placement, and decay testing
• Why micron gauges measure heat transfer — not pressure — and how refrigerant vapor causes false-high readings on the gauge
• The impact of refrigerant retained in compressor oil on vacuum accuracy and the potential role of nitrogen sweeps in displacing refrigerant molecules
• Triple point science: what happens to moisture when pressure drops below 4,580 microns and why liquid water no longer exists below that threshold
• How ice inside a system can allow a deep vacuum pull-down while still failing a decay test, and what that means for cold-climate HVAC work
• The role of heat during evacuation: why adding heat accelerates moisture removal and how deep vacuum increases temperature differential to drive sublimation
• Cold-climate challenges: vacuum pump limitations, micron gauge accuracy at low temperatures, and the physics of dry air in freezing environments
• Triple evacuation and nitrogen purging: whether nitrogen disrupts oil pockets, displaces refrigerant, or both — and why the team wants to test it
• Nitrogen tank quality concerns: the possibility that low-grade nitrogen could introduce moisture and whether an inline dryer would help
• Using system flush chemicals: why Ty cautions against flushing agents and the risks of adding additional chemicals that break down oil
• POE vs. PVE oil chemistry: how POE undergoes hydrolysis when exposed to moisture (creating acid) versus how PVE physically traps water without chemical breakdown
• Dryer strategy for large commercial systems, VRF, and VRV: filter dryer sizing, core pulls, oil sampling, and why an "oil dialysis machine" would be a game-changer
• Plans for future controlled experiments: testing refrigerant effects on micron gauges, ice behavior at various temperatures, and vacuum performance in cold climates
• Industry influence over time: how community-driven knowledge sharing has already shifted vacuum and refrigerant practices over the past decade

Whether you're a residential technician looking to sharpen the fundamentals or a commercial refrigeration specialist wrestling with VRF oil contamination, this episode delivers both practical takeaways and a front-row seat to the scientific inquiry that drives best practices forward. As Bryan puts it: "Don't wait for us — if you want to do the experiment, be part of the conversation."

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Purchase your tickets or learn more about the 7th Annual HVACR Training Symposium at https://hvacrschool.com/symposium.

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This short podcast is from the Bry-X stage of the 7th Annual HVACR Training Symposium: Cheryl Klein's "Surge Protection for HVAC." Cheryl is with DITEK, a veteran-owned company based in Florida, and has extensive knowledge of whole-home surge protection and HVAC-specific surge protectors.

HVAC systems may have their lifespans reduced by power surges (tens of thousands of volts within microseconds) or sustained overvoltage. Surge protectors specifically protect the equipment from power surges, though DITEK manufactures products that help manage sustained overvoltage (and undervoltage, which surge protectors CANNOT protect against). Nearby lightning strikes and high voltage from the utility company (especially after undervoltage) are common causes of surges. Everyone in the country has risks of power surges, but some areas are exceptionally high-risk, whether due to utility causes or climate (lightning storms).

Degradation is the invisible damage that occurs over time with repeated surges. Destruction can be associated with a specific event, like a direct lightning strike or a blown transformer. Surge protection helps with both; when a surge comes through, the surge protector directs the surge to ground instead of your HVAC equipment. DITEK uses thermally protected MOVs (TPMOVs) to redirect the surge; TPMOVs react to surges and change from a low-impedance state to a high-impedance state, effectively pointing the surges to ground, and only a clamped voltage makes it to the HVAC equipment. However, surge protectors will degrade with each event; DITEK's surge protectors have LEDs indicating their health.

NEC 2020 requires surge protection on all dwellings, so many homeowners have whole-home surge protection already installed. Surge protection on the HVAC unit can still be added as an extra layer, which provides better protection for the HVAC system specifically. HVAC surge protection works at the condenser.

DITEK's KoolGuard2 (KG2) is a voltage monitor that works on single-phase equipment under 40 continuous amps. It cuts power if the power exceeds or dips too far below the typical voltage, and then it restores power after three minutes. It also does not require programming, but it has a few best practices, such as reducing lead length to improve the clamping voltage and keeping protected and unprotected wires in separate conduits. Ground must also be within code have low enough impedance to redirect the surges effectively; the resistance can only be measured properly with a megohmmeter or clamp meter. DITEK also has three-phase surge protection for commercial equipment and has options for BAS systems.

Learn more about DITEK's products and DITEK University at https://www.diteksurgeprotection.com/.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Purchase your tickets or learn more about the 7th Annual HVACR Training Symposium at https://hvacrschool.com/symposium.

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Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android.

In this special live panel session recorded at the 7th Annual HVAC/R Training Symposium, the three founders of Kalos Services — Bryan Orr, his father Robert (Bob) Orr, and uncle Keith Huntington — sit down together to celebrate the company's 20th anniversary and answer questions from the audience and online attendees. Hosted by Bert, the conversation blends humor, hard-earned wisdom, and surprising candor about what it actually takes to build and sustain a trades business over two decades. From humble beginnings with $100,000 in startup capital to managing multi-million-dollar commercial contracts today, the founders pull back the curtain on the messy, unpredictable, and deeply human reality of entrepreneurship in the skilled trades.

A recurring theme throughout the panel is that starting a business requires far more than technical skill — it demands grit, personal support, and an almost stubborn refusal to outspend your income. Bryan shares a raw, memorable story about living in a double-wide trailer with seven kids while Kalos was already nine years old, choosing to improvise a drainage workaround rather than take on debt he couldn't afford. The founders agree that the number-one ingredient for small business survival is grit — the ability to wake up the next morning after a terrible day and take the next step anyway. Robert adds a philosophical note that extreme negative emotions in business are almost never accurate; they pass, and tomorrow tends to look better than the night before suggested it would.

One of the most discussed topics in the panel is how to motivate technicians to care about quality — not just revenue targets. Bryan makes a pointed distinction: if you build a compensation system optimized purely for money, you attract people who are only motivated by money. Instead, he advocates building a culture where belonging is tied to quality of work. Practical tools like daily photo-posting of installs in Google Chat, public shout-outs for great work, and peer commentary create an environment where craftspeople hold each other to a standard — not because they're forced to, but because it's who they are. Keith echoes this, emphasizing that most technician frustration stems not from laziness but from unclear systems and expectations set by leadership. When people don't know what's expected, they disengage — and that's a leadership problem, not a people problem.

The panel also dives into the nuances of running a family business, with all three founders offering surprisingly candid takes. Keith notes that the key to 20 relatively friction-free years has been that all three founders are "120 degrees different" from each other — their strengths don't overlap, so they rarely fight over territory. Bryan adds that healthy family businesses require the ability to have real conflict for the sake of mission, not just harmony. He also speaks to the importance of organizational structure when family members are involved: his own son Gavin, at 21 years old, works at Kalos but reports through multiple layers of management precisely so Bryan doesn't micromanage him. The session closes with reflections on the riskiest moments in the company's history — and Bryan's honest admission that four weeks prior to the symposium ranked among the most stressful, as large promised contracts delayed in paperwork can shake even an established business to its core.

Topics Covered

• Expanding HVAC services into electrical and plumbing — what technicians can realistically do and when to partner with specialists
• The real prerequisites for going out on your own: craft knowledge, personal support system, and financial discipline
• Why grit — not capital or credentials — is the single most important ingredient for small business survival
• How to attract technicians who genuinely care about quality, not just technicians who chase commissions
• Using internal tools like Google Chat to reinforce a culture of craftsmanship and peer accountability
• The danger of building systems that look great on paper but don't survive contact with real-world field conditions
• Advice on contractor mentoring programs — how to absorb outside coaching without losing your own identity and standards
• Lessons from running a family business: complementary roles, honest conflict, and the importance of organizational separation
• How Kalos Services grew from $100,000 in startup capital to a multi-trade general contractor over 20 years
• The role of visionary vs. operator personalities in a founding team, and why both are essential
• The founders' biggest career mistakes — including owning full responsibility for a six-figure grocery store power outage
• Why private equity growth models don't translate to owner-operated trades businesses
• Hiring to fill your weaknesses: from permitting to office management, delegating what you hate frees you to lead
• Recommended training resources: HVAC School, Ty Craig / Skill Cat, Ruth King, ESCO, and Dirk Nauman
• Why the riskiest stage of business is never behind you — it scales with the size of your contracts

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Purchase your tickets or learn more about the 7th Annual HVACR Training Symposium at https://hvacrschool.com/symposium.

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Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android.

This short podcast episode is Jeremy Begley's Bry-X session from the 7th Annual HVACR Training Symposium: "Permanent Load Reduction in HVAC – The Hidden Driver of Long-Term Sales."

Some common customer complaints we hear as HVAC contractors include high humidity, high electric bills, noise, and uncomfortable rooms. The typical HVAC solution is to change the equipment or ductwork, such as by downsizing the unit, adding ancillary dehumidification, or modifying the ductwork. If we can't solve the problem, the customer will ultimately choose a different contractor, no matter how hard we try to modify the HVAC system. However, we may be able to use our thorough load calculations to turn our attention to the building and find ways to reduce the overall loads. We expose problems with the structure and can solve them with permanent load reduction strategies, rather than the equipment and ductwork modifications, and serve customers better while earning more money.

Key performance indicators (KPIs) drive money in a business, and ServiceTitan has identified five KPIs closely linked to profit: callbacks, first-time fix rate, warranty claims, comfort complaints, and average ticket. Callbacks are often driven by comfort complaints, which may occur when we modify equipment but not the envelope and vice versa. Warranty claims occur when the equipment can't work as well or efficiently as intended, such as when the load doesn't match the equipment and strains the unit. When we solve these problems, we become trusted advisors and increase customer satisfaction. The customer will continue to work with a company that solves their problems and will recommend HVAC businesses to their family and friends, which also drives sales.

Permanent load reduction requires us to understand load calculations thoroughly, but it's a means for HVAC companies to control outcomes. It requires a mindset change, but when we control system outcomes and increase customer satisfaction, we earn trust and earn more sales in return.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Purchase your tickets or learn more about the 7th Annual HVACR Training Symposium at https://hvacrschool.com/symposium.

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In this long-awaited live episode of HVAC School, host Bryan Orr reunites with three industry veterans — Jim Bergmann of measureQuick, Roman Baugh (Kalos), and Andrew Greaves of NAVAC — to tackle one of the most pressing and underaddressed challenges in modern HVAC: performing refrigerant recovery and system evacuation in extreme cold-weather conditions. The conversation was sparked by a real-world observation from technician Chris Hughes, who relocated from Louisiana to Minnesota and quickly discovered just how different — and difficult — cold-climate HVAC work can be. What follows is an honest, science-heavy, and often humorous deep dive into a problem the industry has largely ignored.

The episode centers on the growing prevalence of cold-climate heat pumps, especially inverter-driven systems capable of operating at extremely low outdoor temperatures. As these systems become the primary heating source in cold regions, technicians are increasingly being called to make repairs — and perform evacuations — in sub-zero conditions. The group walks through why this is such a challenge, examining the fundamental physics that make pulling a proper vacuum nearly impossible once temperatures drop below 40°F. The conversation draws heavily from refrigeration science principles that, as Jim Bergmann bluntly points out, were largely left out of HVAC trade education over the past several decades.

One of the most compelling moments of the episode is Andrew Greaves' introduction of the "heat provocation test," a term he coins on the spot to describe a technique for verifying whether moisture has truly been removed from a system by observing micron gauge behavior after applying external heat to cold-soaked components. This sparks a rich debate between Jim and Andrew about where moisture actually concentrates in a system — in the line set vs. the outdoor unit — and whether heat can realistically reach those areas in a real-world installation. The panel ultimately agrees that heat is the only viable tool when you absolutely must complete a job in cold conditions, but that prevention and scheduling remain the gold standard.

The episode closes with a fascinating dive into the phase diagram of water, specifically the concept of the "triple point" and how it governs moisture behavior at low pressures. Andrew uses a whiteboard diagram to explain why, below 4,500 microns, moisture can only exist as vapor or solid — not liquid — and why that makes sublimation the only removal pathway when heat is absent. Jim adds nuance by describing the self-refrigerating cycle that occurs during deep vacuum pulls, a phenomenon that makes the problem progressively worse the deeper you pull without adding heat. The group wraps up with practical field takeaways and a promise to revisit the topic, including the potential role of nitrogen purging and triple-evacuation techniques in cold-weather scenarios.

Topics Covered

• The rise of cold-climate heat pumps and why they demand refrigerant work during cold seasons
• Why evacuation becomes extremely difficult — or impossible — below 40°F ambient temperature
• The physics of moisture removal: heat energy, vapor pressure, and molecular movement
• Jim Bergmann's real-world demonstration pulling a vacuum to 135 microns on a wet system and still failing the decay test
• Andrew Greaves' "heat provocation test" — using external heat sources to verify dryness after evacuation
• The debate over where moisture concentrates: outdoor unit vs. line set
• Why mini-split manufacturers don't allow permanent desiccant dryers — and workarounds using temporary bypass configurations
• VRF systems and how shell dryers can be temporarily added and then removed post-evacuation
• The self-refrigerating cycle: how pulling a vacuum on ice makes the system progressively colder and more resistant to drying
• Phase diagram of water: the triple point (~4,580 microns) and why liquid water becomes unstable below it
• Why sublimation is the only moisture removal pathway below the triple point
• Gibbs free energy and its role in determining which phase (solid, liquid, vapor) a substance will occupy
• Hot nitrogen purging as a method for carrying moisture out of open line sets
• Push-pull recovery technique to maximize refrigerant removal in cold conditions
• The challenge of vapor recovery in cold weather — leaving multiple pounds of refrigerant behind
• Practical field solutions: insulated tarps, portable propane heaters, belly band heaters, heat guns
• Dry ice cold-trap brainstorm as a creative moisture capture method
• The dual-fuel argument: why Jim advocates for backup heating as the real long-term solution
• How rapid industry growth in the mid-20th century led to mechanics being trained instead of engineers, losing foundational science in the process
• Why this topic matters more now than ever as cold-climate compression refrigeration becomes mainstream

You can watch the original livestream on YouTube HERE.

Learn more about the book Review of Vacuum for Service Engineers or purchase it from TruTech Tools.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Purchase your tickets or learn more about the 7th Annual HVACR Training Symposium at https://hvacrschool.com/symposium.

Subscribe to our podcast on your iPhone or Android.

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Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android.

Training the refrigeration technician is about building technicians who think, not just fix. In this engaging conversation from the 7th Annual HVAC/R Training Symposium, host Trevor Matthews sits down with Billy Carlson to explore what it really takes to develop technicians who think critically and troubleshoot effectively.

Billy shares his journey in the HVAC/R industry, from residential air conditioning to commercial refrigeration, and ultimately specializing in supermarket rack systems and CO2 refrigeration. With only five years in the grocery sector, his company now dedicates 70-80% of its work to refrigeration, with 40% focused on rack systems. This rapid transition offers valuable insights for contractors looking to expand into commercial refrigeration.

Key Topics Covered:

• Building Technicians, Not Just Fixers - Why understanding component flow, P&IDs, and electrical diagrams is crucial for developing thinking technicians rather than parts changers
• CO2 Refrigeration Training - Billy's honest account of learning CO2 systems, including challenges with dry ice formation, charging procedures, and system tuning
• Supermarket Rack Work - The unique pressures and rewards of maintaining systems that hold entire stores, including HFC and CO2 racks with multiple compressors
• Effective Training Methods - Billy's approach to teaching his five-person team, from component identification to reading refrigeration schedules and understanding sequence of operations
• Fine-Tuning Systems - Insights on slowing down ramp rates, adjusting flash tank pressure, and the importance of proper startup commissioning time
• Controls & Communications - Why modern refrigeration technicians need to understand networking, gateways, and digital controls alongside traditional refrigeration knowledge

Billy emphasizes that patience and willingness to ask for help are essential traits for anyone entering supermarket refrigeration. He shares practical tips on charging CO2 systems, avoiding dry ice in lines, working with VFDs, and reading trend graphs to optimize system performance.

Whether you're a residential tech considering commercial refrigeration, a trainer developing curriculum, or a service manager building a team, this conversation offers real-world wisdom on creating technicians who understand the "why" behind every repair.

Check out Refrigeration Mentor at https://refrigerationmentor.com/.

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