HVAC School - For Techs, By Techs

Eric Kaiser returns to the podcast to talk about how copper, piping, and line sets play into systems thinking.

Nowadays, we have to think about POE and PVE oil, and we need to design line sets in a way that assists with oil carry while preventing liquid refrigerant migration. The height of the evaporator relative to the condenser is a major factor to consider during the design phase.

Especially when chases are run underground, we need to watch for possible threats to the copper. Water softener discharge and excess pool water may damage the copper over time, and systems should be designed to keep line sets away from those. In many cases, Florida chases are sealed with mastic, which doesn't prevent water from getting in (but does prevent rodents and insects from entering the home.

Flowing nitrogen is one of the best practices you can do while brazing. Nitrogen displaces oxygen, which contributes to oxidation and produces scale. When cutting copper, you will also want to make sure that you don't get copper shavings inside the tube. The pressure test is also an important step for leak detection. Following the manufacturer's instructions, pressurize the system and apply a liquid leak reactant (bubbles) to joints and other common leak points.

It's a good idea to have at least one line drier in the system, and it should be able to work both ways in a heat pump system. Ideally, the line drier should be in a serviceable location, as it will be easier to detect restrictions when it's on the line set.

Eric and Bryan also discuss:

• Air and vapor barriers
• Long line guidelines
• Underground chase depth
• Derate values
• Controversial reaming/deburring practices
• Line drier best practices

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Eric Kaiser joins the podcast to talk about systems thinking in HVAC. Systems thinking allows us to solve problems and address customers' comfort holistically instead of focusing on just the equipment. The key to systems thinking is to think outside the appliance.

System design plays a major role in performance. Duct design, drain placement, and equipment placement all matter, and we can only do so much to mitigate factors of poor design. We need to assess the building envelope and consider how the HVAC system interacts with it. Building envelope and duct leakage will significantly affect HVAC performance and occupant comfort.

Ventilation also matters, especially since many homes rely on exhaust-only ventilation. However, the air that leaves the building must be replaced, and we often don't control where that air comes from. When you control the source of your fresh air ventilation to meet ASHRAE 62.2, filtration may further help control the quality of the air that comes in.

Installation and commissioning are other things we need to consider when thinking of the HVAC equipment systemically. The wiring needs to be correct, and we need to verify that the system is achieving the proper airflow in the first place. Static pressure is another factor that we must consider during commissioning, as an abnormal static pressure could indicate a filter that doesn't fit or is too restrictive.

It's best to start by looking at the appliance and widening your scope from there until you know about the system as a whole.

Eric and Bryan also discuss:

• Is the house a duct system?
• Oversizing equipment
• Stack effect
• Loose vs. tight houses
• Filtration best practices
• Radiant heat transfer
• Ductwork best practices
• Data trends of cause and effect

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Nathan Orr joins Bryan to talk about some logical fallacies, namely the false cause and strawman. They explain how those fallacies show up in the trade.

It's difficult to present arguments without using fallacies, but people tend to rely on fallacies to uphold extreme religious or ideological viewpoints or conspiracy theories. Fallacies are also often easier to communicate than nuanced science and data.

"False cause" relates to the phrase "correlation does not equal causation." It can be tempting to link coincidences and say that one thing causes the other, but that could very well not be true. For example, more compressors fail during lightning storms. It's reasonable to assume that lightning causes the failures, but lightning is not simply striking all of the compressors; other power outages and other conditions that happen during storms are more likely plausible causes.

Confirmation bias also makes it easy to cling to a false cause. People are likely to disregard data that doesn't align with what they already believe.

A strawman misrepresents (or deliberately misstates) another argument to make it easier to attack. People often apply the strawman fallacy to conversations about forming ice in a system during vacuum and duct sizing. Strawman arguments happen more often in business matters, especially if people impugn the intentions of the other party.

In many cases, being open to new information will prevent you from falling prey to logical fallacies.

Nathan and Bryan also discuss:

• Flat-earthers
• Inverter board failures at night
• Evaporator coil corrosion
• Simultaneous capacitor and fan motor failures
• Logical fallacies in chance and gambling
• The pitfalls of anecdotal evidence and small samples
• Appeal to emotion
• Defining "better"
• Mounting TXV bulbs
• Heuristics and mental shortcuts

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Refrigeration Mentor founder Trevor Matthews returns to the HVAC School podcast to talk about personal development and training, including tips for learning in HVAC/R.

When you're looking at a problem in the field or in training, it pays to take a step back, cool down, and reevaluate your mindset. Trevor recommends thinking about the worst-case scenario and seeing how you can either prevent it or grow from it. It's good to walk away for a little bit anytime you feel like you're overanalyzing anything so that you don't make blunders.

Trevor has found that reading books is one of the best ways to learn about HVAC/R. HVAC/R professionals can greatly benefit from investing in themselves and setting up their own self-directed training programs. Trainers and mentors can't be the only ones motivating HVAC/R professionals, holding them accountable, and stimulating their growth.

Many times, our own limiting beliefs of ourselves hold us back, and we need to convince ourselves that we can learn difficult things, even if it isn't easy. We can also limit our ratio of entertainment to education; focusing more on the latter can greatly benefit your personal development.

Setting educational goals is also difficult when we work long hours and simply don't have the time or energy to invest in ourselves. The industry needs reform, and reform that raises base rates and prevents an over-reliance on overtime might also attract some new professionals to the field.

Trevor and Bryan also discuss:

• Trevor's new podcast
• Clearing your head
• Books about doing the hard things first
• Autodidactism and "learning how to learn"
• Subconscious cost-benefit analysis
• The industry's addiction to overtime
• Helpful books and podcasts for personal development
• Getting rid of "tunnel vision"

Recommended book/podcast list:

• Eat That Frog!: 21 Great Ways to Stop Procrastinating and Get More Done in Less Time by Brian Tracy
• How to Win Friends & Influence People by Dale Carnegie
• QBQ! The Question Behind the Question: Practicing Personal Accountability at Work and in Life by John G. Miller
• Mindset: The New Psychology of Success by Carol S. Dweck
• Grit: The Power of Passion and Perseverance by Angela Duckworth
• Mastery by Robert Greene
• Good to Great: Why Some Companies Make the Leap and Others Don't by Jim Collins
• Built to Last: Successful Habits of Visionary Companies by Jim Collins
• Entreleadership: 20 Years of Practical Business Wisdom from the Trenches by Dave Ramsey
• Culture Code: The Secrets of Highly Successful Groups by Daniel Coyle
• Discipline Without Punishment: The Proven Strategy That Turns Problem Employees Into Superior Performers by Dick Grote
• Atomic Habits: An Easy & Proven Way to Build Good Habits & Break Bad Ones by James Clear
• Rich Dad Poor Dad: What the Rich Teach Their Kids About Money That the Poor and Middle Class Do Not! by Robert T. Kiyosaki
• The Richest Man in Babylon by George S. Clason
• The Big Short: Inside the Doomsday Machine by Michael Lewis
• Antifragile: Things That Gain from Disorder by Nassim Nicholas Taleb
• Think and Grow Rich by Napoleon Hill
• The 5 AM Miracle Podcast
• The Mindvalley Podcast
• Hidden Brain Podcast

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In this short podcast episode, Bryan shares some of his top threaded connection tips. He also clears up some confusion about connection types.

Threaded connections include flare and compression-type fittings (like chatleff or Aeroquip fittings). The threads don't actually make the seal; the pressure pushing the surfaces together is what makes a seal.

Bryan doesn't recommend putting traditional thread locks on flares, but refrigerant oil or mild assembly lubricants can help the flare come together more smoothly without imperfections. However, you need to be careful when using a torque wrench and use the lowest acceptable specification to avoid over-torquing.

Leaks are common problems with flare fittings, but those often happen in cases where flares are poorly made. Scored faces, loose flares, and over-torqued flares are common causes of leaks. However, many modern flaring tools can make perfect flares quite easily. You must also remember to deburr the copper for the best results.

Compression-type fittings often have O-rings, which are the parts that actually do the sealing. (Leaks WILL happen without the O-ring in place.) You can use an assembly lubricant with these fittings, but you still have to be mindful of torque spec adjustments.

Pipe-thread connections actually rely on the threads, not pressure or an O-ring, to create a seal. Pipe dopes (or thread sealants) tend to be best on these connections, but you want to leave the last couple of threads bare so that pipe dope doesn't get into the system.

As with brazed and soldered joints, the copper used for threaded connections needs to be cleaned, cut squarely, and deburred for best results.

Bryan also covers:

• Assembly lubricants
• Brazing vs. soldering
• Zoomlock
• IMC 1107.5.4
• Protecting seals during brazing and soldering

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Bryan explains how parents and educators can succeed at giving kids the tools for any job they want. This podcast was originally a presentation at the 2022 FPEA Florida Homeschool Convention.

Jobs, careers, and vocations have changed a lot over the years. Even though those have changed over the years, parents still want their kids' vocations to develop character, foster growth, and bring joy. While kids are young, parents can instill values of grit and diligence; however, parents have to overcome the challenges presented by the instant gratification provided by technology.

Interest-guided learning is a double-edged sword, as it allows a child to pursue their interests but can cut them off from the interest of others. Developing the values of kindness and deference can temper the negative effects of interest-guided learning while maintaining the benefits of interest-guided learning. If a child has an interest in something and can pursue that interest on their own by demonstrating autodidactism, they open themself up to a lot of vocational options.

Nowadays, it's a lot more common for people to hold many different jobs or vocations over their lifetime. Encouraging a child to learn different skills allows them to explore non-linear career paths more easily than children who don't learn useful skills. When teaching children, developing mental models and an appreciation for learning is another key to success across vocations.

Bryan also talks about:

• Vocation vs. avocation
• Grit vs. talent in the pursuit of success
• Modeling and practicing gratefulness
• Transferable skills
• Feeling "stuck" in a vocation
• Visualizing average molecular velocity
• Learning about humidity and electrical movement
• Striking a balance between joy, service, and passion
• Expectations vs. standards
• Pursuing college, business ownership, and other career opportunities

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In this short podcast episode, Bryan talks about ERV and HRV technologies, including their appropriate applications and limitations.

HRVs are heat recovery ventilators (not to be confused with heat recovery units or HRUs), and ERVs are energy recovery ventilators. The main difference between these two lies in the type of heat they move; HRVs only move sensible BTUs, whereas ERVs move sensible and latent BTUs.

As you bring air in from outside, you're discharging roughly the same amount of air (though modern technologies allow you to manipulate the pressure a bit more). The goal of the HRV or ERV is to recover some energy from the air exiting the structure and incorporate it into the incoming airstream. The airstreams cross over each other, and there is heat transfer but not air mixing. (ERVs also allow for the exchange of moisture.) Two fans drive the direction of energy flow, and a mesh or a porous desiccant medium facilitates the interaction between the airstreams.

You will get some energy savings with an HRV or ERV, but savings are dictated by the amount of air moved and the temperature differential between the airstreams. In general, you will see HRVs up north (in low-humidity markets) and ERVs down south (in higher latent-heat markets). However, even ERVs aren't very effective in conditions with low energy transfer and high moisture UNLESS they're used with a ventilating dehumidifier.

Bringing in fresh air is good for indoor health and safety, as it helps dilute the presence of VOCs, viruses, and harmful gases. HRVs and ERVs help us manage the air we bring in.

Bryan also covers:

• Integrating ERVs with bathroom ventilation
• Safety considerations to consider for outdoor air
• Positive pressurization
• Demand ventilation with CO2 sensors
• Learning about ASHRAE 62.2

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Rajan Rajendran and Jennifer Butsch from Emerson join the podcast to discuss the Helix and some refrigerant changes that are coming. Jennifer is the Director of Regulatory Affairs, and Rajan is the Global Vice President for Environmental Sustainability and former director of the Emerson Helix.

Lately, there have been more environmental efforts to reduce greenhouse gas emissions, and plenty of large corporations have "net zero" initiatives. Sustainability requires a holistic, systemic approach in our industry; the Helix Innovation Center conducts the research needed for us to handle these sustainability initiatives as effectively and safely as possible.

However, the sustainability initiatives frustrate a lot of technicians. There will likely be multiple refrigerant transitions as our industry progresses. Education and knowledge provided by manufacturers and HVAC organizations will be the key to smooth transitions.

Many of the replacement refrigerants, including R-32 and R-454B, are A2Ls. These mildly flammable refrigerants have different handling, transportation, and charging procedures than what we're used to. However, we are unlikely to see changes in oils; POE and PVE oil will likely remain dominant in the market.

Eventually, we may see more GWP changes. We would also be prudent to focus on preventing and rectifying equipment leaks. Proper maintenance will help us navigate current and possible future changes.

Rajan, Jennifer, and Bryan also discuss:

• The AIM Act and HFC reduction in 2024
• GWP-limit petitions in HVAC vs. refrigeration
• Refrigerants that manufacturers are embracing
• Refrigerant testing processes
• Natural refrigerants
• The weight of refrigerants vs. the weight of air
• Evaporator coil manufacturing and leakage
• Built-in leak detection
• Refrigerant pricing

To learn more about these coming refrigerant changes, check out the AHRI Safe Refrigerant Transition Task Force's resources HERE or Emerson's E360 Platform HERE.

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In this short podcast episode, Bryan talks about pilot controls. He talks about the old-school ignition systems on gas appliances and some similar pilot functions on residential A/C units and heat pumps.

When we think about a pilot light on a gas appliance, we can think of it as a small standing flame that sits there ready to ignite the burner whenever gas is flowing. Pilot lights were necessary for old-school gas furnaces, and many of those pilot lights worked with a thermocouple. In many older furnaces, pilots also prevent excessive carbon monoxide from unspent gas. In other words, the pilot is not the main burner; it merely sets up the main burner.

On a typical A/C system, the 24v power is similar to a pilot on a gas appliance; the 24v "pilot" control energizes the system and has a small amount of voltage (compared to the high voltage needed for all of the components to work).

The reversing valve on heat pumps also has a pilot valve; the 24v signal activates the pilot valve with the solenoid, which redirects system pressure to allow discharge gas to slide the valve. That's also why you can't shift the operating mode when the system is off. Solenoid valves in general tend to have pilot functions; they rely on a refrigerant pressure differential that results from 24v electrical signals, not the signal itself.

In short, we don't rely on the pilot light or the 24v electrical signal to power the entire equipment. Pilot controls merely help the equipment get started; they have less load on them and trigger or control parts and processes that are more complicated.

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Bryan and Robert Orr continue their discussion about ethics by talking about what it means to have grit and discipline in business. They talk about what those characteristics look like in business and in life, and they mention some good books.

Grit is a trait that can contribute to an ethical way of life; showing grit means that you follow through with a project until you get the results you want. Both physical and emotional grit are strengths, and those things tend to be more important than talent in our field.

Compared to discipline, grit is a lot more closely intertwined with a person's emotional condition. When we encounter overwhelming negative emotions, grit is the quality that allows us to power through the current state of affairs. Discipline and grit are both based on commitment and resolve, but discipline deals more with actions rather than feelings. Discipline is more about habits, balance, and wisdom.

A belief system or set of guidance is what drives discipline. Discipline can also be repetitious and boring, but it can take you farther than raw talent if you dedicate yourself to your belief system, sources of guidance, and goals. Developing discipline requires us to establish habits and sequence those habits. Good leaders and parents are the ones who establish those habits for employees or children.

However, something to keep in mind is that both grit and discipline can amplify a person's bad characteristics.

Robert and Bryan also discuss:

• Grit vs. talent (Angela Duckworth)
• Does grit count as an ethic?
• Discipline and delaying gratification
• Developing grit over time
• "Real" vs. "true" emotions and thoughts
• The downfalls of raw talent
• Thinking about obstacles in a healthy way

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