HVAC School - For Techs, By Techs

Latest Episodes:

Combustion Venting Categories - Short #189 Mar 19, 2024

Show notes

In this short podcast episode, Bryan talks about the four different combustion venting categories for gas appliances as set by ASHRAE and where you'll see them. He also shares some notes about pressurization.

These categories deal with the pressurization and temperature ranges of the vents. Category 1 venting is used for old-school open-combustion gas furnaces; they have high flue gas temperatures and are considered low or mid-efficiency furnaces. This venting category is not positively pressurized, and it has a single-wall flue and operates more like chimneys, as the appliance is usually under negative pressure; a draft is created and draws the flue gas out. It's non-condensing, negative-pressure venting.

Category 2 venting is not common anymore; they operate with negative pressure in the vent, and condensation is still likely.

Category 3 venting is non-condensing positive-pressure venting. These are more common in older through-the-wall appliances.

Category 4 venting is condensing, positive-pressure venting for high-efficiency or condensing gas appliances with lower-temperature flues and sealed combustion. PVC is the most common venting material for these furnaces. We can recover some energy from the condensation process.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE."

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

The Gift of Security and Learning w/ Jennifer Manzo Mar 14, 2024

Show notes

In this episode of the HVAC School Podcast, host Bryan Orr speaks with Jennifer Manzo, founder of HVA-Chicks Coalition. Jennifer shares her unique background as a longtime teacher and homeschooler who stumbled into the HVAC trade while researching vocational options for her homeschooling students.

They discuss the inspiration behind HVA-Chicks, a free training coalition offering technical, career, and personal support to women in HVAC. This includes customized training plans, connecting members with childcare assistance, legal support for discrimination issues, job search help, and more. Jennifer also manages a free 24/7 tech support phone line with several experienced volunteers. She explains why she dedicates endless hours to serving others in the industry at no cost - to provide the help and community she wished for when first starting out.

Jennifer actively works to build women up by first offering them psychological safety and security. When women feel unconditionally cared for, they gain the internal strength and courage needed to push past obstacles in this male-dominated field.

Key topics covered:

· Jennifer's journey from teaching to HVAC

· Lifelong learning

· Overview of HVA-Chicks Coalition offerings

· Managing a free 24/7 tech support phone line

· Motivations for serving the industry with no payment

· Providing psychological safety/security for women technicians

You can learn more about the great resources HVA-Chicks has to offer at https://hvachicks.com/, visit Skillcat to check out the blog where Jennifer writes, and find Jennifer on social media as Hvachicks Jennifer. You may contact Jennifer by her public email at jennifer@skillcatapp.com.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE."

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

Belt Talk - Short #188 Mar 12, 2024

Show notes

In this short podcast episode, Bryan dives into some belt talk, including some bits about pulleys and sheaves. He also shares some belt tensioning tips for your next commercial HVAC job.

Belts are less common than they used to be, but we find them in ventilation fans, RTUs, and AHUs. Squealing belts indicate slippage, which indicates fan inefficiency and energy losses. Belts transmit energy from the motor (pulley) to the fan or blower wheel being driven by it. Motor mounts may be adjustable, but there will be a means of adjusting the tension of the belt. Before we change or replace a belt, we need to make sure the belt is properly aligned (centers should have the proper distance and pitch). Common sense and good observation skills will be your best tools.

Adjustable sheaves shouldn't be touched when you're changing the belt; the adjustment of the sheave is for airflow based on the RPM of the fan motor, not tensioning or setting amperage. We set belt tension by tensioning with a specific tool: a belt tensioner. Belts should be as loose as possible without slipping, but belts will loosen a bit over time and with everyday use, and they may slip eventually. Wear on the pulleys may also cause belts to slip.

Cogged belts, also called notch belts, may bend more easily, last longer, and be more efficient due to reduced resistance (compared to non-cogged belts). Belt efficiency can also be affected by alignment and tightness (being too tight).

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE."

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

Using the Roomulator w/ Chris Hughes Mar 07, 2024

Show notes

In this episode of the HVAC School Podcast, host Bryan Orr speaks with Chris Hughes of The Energy Conservatory (TEC) about using the Roomulator card and DG-8 manometer for room pressurization testing.

Chris provides background on how he came up with the idea for the Roomulator. He wanted an easy way for technicians to properly size passive returns to relieve pressure imbalances between bedrooms and the main body of a home. The Roomulator card enables technicians to quickly measure door undercuts and size transfer ducts, grilles, etc., to reduce room pressures to 3 Pascals or less per ENERGY STAR guidelines. When paired with the DG-8 micromanometer, the system provides precision room pressurization measurement.

They discuss reasons why excessive room pressures can cause comfort, efficiency, and indoor air quality issues. Removing positive pressure helps reduce airflow through leaks in exterior walls, lighting fixtures, etc. Chris also talks about how the Roomulator is an affordable "gateway tool" for technicians to get started with building science and air pressure dynamics. DG-8 allows technicians to perform several other tests beyond room pressurization as they advance their skills.

Key topics covered:

TrueFlow grid and DG-8 manometer
Origins and purpose of the Roomulator card
The step-by-step process for using Roomulator and DG-8
Impacts of room pressurization on comfort, efficiency, IAQ
Role as an introductory tool for building science testing
The collaboration of NCI and TEC

You can learn more about the Roomulator and purchase a few at https://store.energyconservatory.com/roomulator.html.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE."

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

Primary & Secondary Air in Combustion - Short #187 Mar 05, 2024

Show notes

In this short podcast, Bryan dives into a gas heating topic: primary & secondary air in combustion.

Primary air is the air and oxygen content that enters the furnace BEFORE combustion. In older furnaces, prior to induced combustion, air was drawn in through the front. These older furnaces had adjustable shutters that we could modify to bring in more or less primary air based on our combustion analysis readings. We could also use flame color to get an idea of the CO content (yellow tips on the flames indicate higher carbon monoxide content).

In systems like those, air is drawn in via Bernoulli's principle; there are areas of low pressure around areas of high velocity. There is pressure associated with the natural gas, which draws air into the burner. Nowadays, we have induced draft systems (not to be confused with power-vented systems) to draw air in at a fixed rate for more consistent combustion. These inducer fan blowers are necessary for the more complicated heat exchangers we see in more recent furnaces. Secondary air is the air after combustion.

We only want to adjust primary air if we have the correct gas pressure, so we will want to make sure we perform combustion analysis. We can also clock the meter (if applicable), but you will not always have a meter, and you will want it to be informed by combustion analysis.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE."

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

Learning Outside the Box (Live Rebroadcast) Feb 29, 2024

Show notes

This podcast episode is a live rebroadcast of a livestream with Craig Migliaccio (AC Service Tech) and Ty Branaman (love2hvac). It focuses on different types of learning and how to make the most out of learning experiences.

The hosts discuss the differences between random learning, goal-driven learning, and forced learning. Random learning involves casually exposing yourself to new information without a specific end goal. It can be useful for sparking curiosity. Goal-driven learning is focused on achieving mastery of a particular topic in order to solve a problem or accomplish something concrete. This type of learning requires effort but tends to be the most effective. Forced learning is when someone else compels you to learn certain material, often for compliance reasons; this type lacks intrinsic motivation.

They emphasize surrounding yourself with a community of curious people who can provide encouragement, accountability, and inspiration. Events like the HVACR Symposium and AHR Expo facilitate making these connections. Building personal relationships and enjoying the humanity in the field sustains interest and passion.

Key topics covered:

The role of books, podcasts, conferences, and interpersonal interactions in learning
Differences between propositional, procedural, perspectival, and participatory knowledge
Using the Socratic teaching method of asking leading questions
Understanding real-world applications of Ohm's Law
Distinctions between random, goal-driven, and forced learning
Finding joy and connection through education and community
Networking with people across the industry at trade events

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE."

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

Making Family Business Work w/ Leilani Orr Feb 22, 2024

Show notes

In this podcast episode, Bryan has an enjoyable conversation with his wife Leilani about navigating family relationships while building a business. They discuss the challenges and benefits of mixing family and work, setting boundaries, and maintaining perspective.

Bryan starts by admitting he felt intimidated to have Leilani on the podcast before, joking about her "big muscles and dominating presence." Leilani jokes back, saying Bryan seems less intimidated now that they've been together so long. They then dive into the topic of starting their family business, Kalos, back in 2005.

Leilani remembers feeling excited but also some "pain" around Bryan turning down a big raise to go out on his own instead. She was impressed he felt so confident to leave the security of a paycheck, which made her believe Kalos would succeed. However, as a young couple they were already not making much money, so the pay cut hurt.

Other topics they discuss:

Holding morning meetings with employees in their small home when Kalos was just starting out
The awkwardness Leilani felt sometimes hearing family members complain about each other or the business
How they've generally had good boundaries between family issues and personal relationships
Funny stories about occasionally discussing business at improper times around non-family friends
Taking on jobs outside Bryan's wheelhouse (like painting) in the early days out of necessity
The importance of being willing to do work others may see as "below them" to make a small business succeed
How Bryan easily gets bored doing repetitive tasks, and prefers to delegate
Leilani's appreciation that Bryan respects her contributions to the family and doesn't compete with her for time
The need for humility and perspective when running a family business

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE."

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

Heat Pump Basics in Plain Language Feb 15, 2024

Show notes

In this solo podcast, Bryan provides an introduction to heat pumps, explaining the basics of how they work and key considerations in a way that is easy for anyone to understand. He starts by reviewing some core HVAC principles - that heat moves from higher temperatures to lower temperatures, the three main methods of heat transfer, and the concept that temperature is really just a measure of molecular movement.

He then explains that a heat pump works by taking heat from a place that doesn't matter, like the outdoors, and putting it where it is wanted, like inside a home. This is the opposite of an air conditioner. The only difference in the actual equipment is the addition of a reversing valve to change the direction of refrigerant flow and a defrost control board. He talks about the need to defrost the outdoor coil when ice builds up and what happens in that mode.

Some key challenges and design considerations he covers when using heat pumps include: dealing with defrost and where the melt water will go, keeping the outdoor unit free of snow, supplemental heating systems for when the unit can't keep up, increased electrical load, and factors like the climate zone, home efficiency, electricity prices, and infrastructure. He emphasizes that with good design focused around heat pumps, they can work efficiently even in cold climates.

Topics covered:

· Basics of heat transfer

· How heat pumps move heat

· Reversing valve and defrost board

· Defrost challenges

· Supplemental heat

· Sizing and design considerations

· Use in cold climates

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE."

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

Women in HVAC (Live Rebroadcast) Feb 08, 2024

Show notes

This podcast brought together several women working in the HVAC industry to discuss their experiences and offer advice. The conversation focused on the positives of working in HVAC as a woman, the importance of community, and the resources available.

The women talked extensively about how welcoming and supportive the HVAC community, and particularly HVAC men, have been towards them. Several got into the industry because of their husbands' work. They agreed the perception that it's difficult for women to break into HVAC does not match their largely positive realities. The biggest challenges they identified related more to things like clothing and bathroom options rather than discrimination or harassment.

Advice offered for companies looking to hire more women focused not on targeting women specifically, which could cause resentment, but on ensuring good benefits, upholding anti-discrimination standards, and facilitating connections with other women in the industry. Several mentioned the value of groups like Women in HVAC and the Society of Women Engineers for networking and support. Attending conferences to connect with the HVAC community was also repeatedly recommended.

Overall, the positive tone revealed that with the right connections, women can thrive in HVAC careers. All expressed passion for their work and eagerness to encourage more women to explore the industry.

Topics covered:

Getting into HVAC
Challenges for women in HVAC
Advice for attracting/supporting women
Importance of community
Groups like Women in HVAC
Conferences/events

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE."

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

History of AWG - Short #186 Feb 06, 2024

Show notes

In this short podcast, Bryan explains the history of AWG, or American wire gauge, which is the sizing system we use for conductors in the United States.

Wires weren't standardized before the 18th century (1700s). As fencing, telegraph, and electrical wires started coming out, there was a need for a standardized system. In England, a standardized system called the Birmingham wire gauge (BWG) was developed in the 1800s. The American Telegraph Company developed the American equivalent, the AWG, shortly afterward. These systems standardized wiring diameters, and the AWG's wire sizes get bigger as they get lower (including NOT wires, which are noted by the number 0 on the gauge, like 2/0).

The AWG scale is a logarithmic scale, meaning that the wire sizes don't vary by a fixed amount; there is a 20% variation between diameter sizes. Our brains are programmed to understand proportionality (i.e., logarithmic values and patterns) better than discrete values. This sizing system based on a logarithmic scale makes it easier for us to observe differences between the diameters.

The metric system for wire sizing is NOT logarithmic; there is a root-10 progression between sizes; this standard is called IEC 60228.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE."

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

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