In this short episode of the HVAC School podcast, Bryan and Tom Lorenz from Copeland talk about the new Sensi equipment interface. This product has been in field trials for months and will be launching in February. It will also be featured at the 2025 AHR Expo in Orlando. You can learn more about when and where the product launch will be at AHR at https://ahr25.mapyourshow.com/8_0/sessions/session-details.cfm?scheduleid=197.

Sensi is launching the new Sensi equipment interface module (indoor and outdoor), which eliminates the need to pull additional thermostat wire, and it's great for upgrades from A/C units to heat pumps or single-stage or multi-stage units. These have a strong wireless connection that can be picked up approximately 100 feet through walls.

The ideal indoor application will be whenever you have single-stage to multi-stage upgrades and can't pull more wires. Outdoor applications are best for A/C-to-heat pump conversions and upgrades from single-stage to multi-stage. This module also contains outdoor sensors and can work with accessories like dehumidifiers. The Sensi equipment interface module has been tested in extreme weather conditions and has proven its durability.

These will be launched as part of a kit with indoor and outdoor modules and a Sensi Touch 2 smart thermostat. The Sensi Touch 2 will also receive an upgrade to make it compatible with the new Sensi equipment interface module. The Sensi equipment interface module will also come with contractor branding capabilities, which is an option for Sensi smart thermostats and traditional White-Rodgers thermostats.

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 episode, Bryan talks about the standing pilot gas systems and the ignition strategy in gas-fired appliances.

Standing pilots are very simple devices that are common in fuel logs, water heaters, and some pool heaters. These devices have a thermocouple or thermopile; in a thermocouple, two dissimilar metals are connected at one end, and there is an electron flow between the metals when one is heated up. A thermopile is a collection of thermocouples in series or parallel to generate more millivolt signals. (Both of these can be damaged if cleaned; don't mistake these for the flame rod! Flame rods can be cleaned with a delicate material.)

To use a standing pilot, turn the dial to the pilot mode and press it in, which allows gas to come through the pilot. Then, you can light the gas (with a lighter or spark mechanism) and keep the dial depressed until there is enough heat generated on top of the thermocouple or thermopile, which allows it to lock in and keep the pilot lit (and pass the entire safety circuit). Then, you turn the gas valve on and let the main burner take over.

If one safety is open, the entire circuit breaks to prevent unspent fuel from accumulating and causing a dangerous condition. One of the main challenges with standing pilots is that they are prone and very sensitive to corrosion due to the low voltage and current. Clean and tight connections can mitigate these risks.

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 6th 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

Jim takes us all the way through the history of furnaces, from the Stone Age when he was a child to modern modulating condensing types.

The goal of a furnace is to move heat, so a furnace uses heat exchangers to facilitate heat transfer. Furnaces have primary and secondary air. The primary air goes through the burner, and the secondary air goes around the flame and is pulled in around the heat exchanger inlet. So, the flame's heat creates a draft that pulls air in.

Natural gas and oil (LP/propane) furnaces are common nowadays, but we initially burned wood and coal in furnaces. The first gas furnaces came into existence by modifying coal, not from the gas lines we see nowadays. Long ago, the flue gases were also exhausted to the basement; CO poisoning was less of a concern back then, as combustion was usually complete. Burning the building was a much more severe risk.

The first “gas crisis” in the 1970s forced us to focus on gas furnace efficiency. In that time, we developed spill switches and retrofit kits that converted furnaces over to spark ignition. In the 1980s, we came out with the draft-induced 80% furnaces we see nowadays. We also eliminated standing pilots and draft diverters. Even though the appliances became more efficient, we didn't actually burn the gas any more efficiently.

So, despite the technological advancements we've made over the years, we don't actually burn gas any more efficiently than we did in the 1930s. However, our modern furnace technology has eliminated standby losses, controlled ignition, and focused on the role of latent heat in combustion.

Jim also discusses:

• Flame color and types
• Draft hoods and diverters
• Products of complete combustion
• Excess air: a double-edged sword
• Natural ventilation
• Efficiency percentages
• Furnace testing and ratings
• Turbulators
• Modulation

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 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium.

Take the HVAC School Industry Pulse Survey by WorkHero at https://hvacrschool.com/workhero.

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In this short podcast episode, Bryan talks about heat exchangers and temperature rise in gas furnaces, especially 80% open-combustion gas furnaces.

Temperature rise is the difference between the return air temperature and supply air temperature; in cooling, we usually refer to this difference as a delta T or temperature split. The manufacturer sets a target range on the data plate; high-efficiency furnaces tend to have lower temperature rise targets than mid-efficiency or older furnaces. We want to heat the space and not waste heat on surfaces (like duct surfaces). For that reason, the goal is to stay in the middle of the temperature rise range or slightly on the lower side for peak efficiency, better heat transfer, proper airflow, proper venting, and protection of the heat exchanger.

In mid-efficiency furnaces, we don't want the temperature rise to be too low, as cooler gases can condense. High-efficiency condensing furnaces have a dedicated condensate system, but 80% furnaces do not. That condensation can corrode the heat exchanger, which makes it vulnerable to cracks. Cracked heat exchangers may also happen when the temperature rise is too high, and they are dangerous due to carbon monoxide (CO) leaks; check for abnormal flame movement and color. Lower-temperature air is also uncomfortable if the registers are in locations where blowing air on people is inevitable.

We can reduce the temperature rise by increasing the heating airflow, which can sometimes be done by re-tapping constant-torque and PSC motors or changing ECM settings. However, restrictive filters and ductwork may also cause that problem, and they need to be addressed.

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 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium.

Take the HVAC School Industry Pulse Survey by WorkHero at https://hvacrschool.com/industrypulse.

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

In this short Q&A podcast episode, Bryan answers a listener-submitted question and gives some of his tips for moving to HVAC sales from field technician/installer roles. The world of sales has a different pay structure, which makes it an appealing option to many technicians.

Salespeople need to be able to have money conversations with confidence and not be afraid to talk about pricing. You can practice these conversations with friends or fellow technicians, including answering questions and responding to objections.

Sales confidence is another key to success in sales. Many successful sales techs go into sales with the assumption that the client wants to work with them and aren't timid because they're confident they'll make the sale. Great salespeople also seek out feedback to learn and grow from.

Many great salespeople in the HVAC industry also benefit from learning about load calculations, equipment selection, and duct design, particularly via the ACCA manuals and software like Wrightsoft and Kwik Model 3D. The HVAC Grapevine, NCI, and TEC all have great educational resources about building science. Deploying test instruments, including blower doors, duct blasters, and thermal imaging cameras, also gives you vital information about the structure and shows clients that you're going above and beyond for their comfort; you're delivering quality and doing so with integrity.

Communication skills are a crucial part of sales, and the best thing you can do to start honing your communication skills is to ask good questions and listen for valuable answers. Empathy is also important in sales, and it's most effective when you can understand your client's priorities.

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 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium.

Take the HVAC School Industry Pulse Survey by WorkHero at https://hvacrschool.com/industrypulse.

Subscribe to our podcast on your iPhone or Android.

Subscribe to our YouTube channel.

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