BACK

Weird Transformer Talk

By Bryan Orr Eric Mele

Make & share a podcast clip

Keep the exact passage and a link to the full episode. Choose up to three minutes, with enough context to be fair to the speaker.

Start End

Preview uses this episode’s audio. Browser audio export, when supported, takes the length of the selected clip. Nothing plays until you choose Preview.

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, you’ll measure 24v. However, if you connect a lead to ground, you’ll still read 24v. (Don’t ground both, or you’ll get a short.) Ground is just a path back to the power source. Electrons don’t suddenly “leak” from something connected to ground.

Grounded and neutral conductors can potentially be dangerous. There can still be potential even though your leads wouldn’t pick it up. In residential HVAC, we’re used to seeing neutral and ground connected at the main distribution panel. However, it’s not always okay to connect ground and neutral or use ground as a current-carrying conductor.

If you’ve got split-phase power going into a regular home, you’ve got 120 volts 180 degrees out of phase with each other. If we don’t have a center-tap neutral, it would function similarly to a 24v transformer. In that case, it’s not necessarily unsafe to read 0v on neutral. We get tripped up because we think in terms of using a meter, not in terms of actual potential voltage.

In a delta configuration, you will have a high leg connecting to neutral (B phase is usually high; A and C phases are usually normal). You can’t really center-tap a delta, so you have to tap the center of one phase.

Eric and Bryan also discuss:

Working out of a truck vs. a van
Shunting high-voltage spikes to ground
Center-tapped transformers and “wild legs”
Ground is NOT necessarily the earth
Hot legs on the primary AND secondary

Learn more about Refrigeration Technologies HERE.

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

Work through this with the trade.

Highlight a short passage, or bring a question about a specific moment into HVAC No Bull Forum.

Discuss this reference → Related forum discussions

Comments

Deliver High Performance Heat Pump Retrofits w/ David Richardson

Did You Actually Test Every Heat Strip – Short #311

Uncovering the Root Causes of Commercial Refrigeration Failures

Why and How to Test Heat Pump Defrost – Short #310

Building a Business That Lasts: Why Culture Beats Strategy in HVACR w/ Tony Gonzalez

Tight Enough to Fail – Short #309

Glycol Skids for Market Refrigeration w/ Max Johnson

Your Thermostat Is Reading the Wall – Short #308

Next-Gen Filtration – Pressure Drop, MERV 16, and Bypass Prevention w/ Chris Howells

The Fuse Only Blows When You Leave – Short #307

Author:

Bryan Orr

Company: Kalos Services

Position: Co-Founder and President

Eric Mele

Check out our most recent video

How to Evacuate an AC system, Full Vacuum Procedure

Our latest Podcast

HVAC School – For Techs, By Techs

Real training for HVAC ( Heating, Ventilation, Air Conditioning and Refrigeration) Technicians. Including recorded tech training, interviews, diagnostics and general conversations about the trade.

Heat pumps may be everywhere, but according to David Richardson, the industry is in danger of aiming at the wrong target. In this 2026 HVACR Training Symposium session, the Kentucky contractor’s son, who has never lived in a home without a heat pump, opens with the story of Olympic rifle shooter Matthew Emmons. Emmons hit the bullseye with perfect precision in 2004, only to discover he had fired at the wrong lane’s target. Richardson argues that contractors risk the same mistake when they treat the heat pump itself as the goal and market it with the same “magic” promises used in the 1970s, a pattern that led to poor installations and a reputation problem that has lasted 50 years.

The real target, Richardson says, is the customer, and the heat pump is only one ring on that target alongside ductwork, the building envelope, equipment sizing, noise, and expectations. He distinguishes between HVAC equipment, which anyone can sell, and the HVAC system, which is where a contractor’s skill and craftsmanship show up. Average installations, he notes, deliver roughly 57% of rated performance, while a high-performance retrofit aims for 88% or better. With “free heat pump” offers likely coming next, he urges contractors to differentiate through engagement, education, clear expectations, and measured results, ending with what he calls a “craftsmanship receipt.”

The heart of the talk is five practical tips. First, learn what the customer is really after and set expectations early, including what a defrost cycle looks like. Second, don’t inherit a bad duct system, and use pressure, airflow, and temperature measurements to find problems before they become yours. Third, don’t inherit a bad building, since the structure works like a duct system and can undermine a perfect install. Fourth, bring the customer along by putting simple tools in their hands, such as a thermal camera or flow hood, and translating data into plain language. Fifth, follow a repeatable process that defines where testing begins and where additional paid services start.

Richardson closes with a call to document lessons learned, including mistakes, and to build these practices into company culture. His message is that heat pumps aren’t magic, but they can perform as if they were when installed well and priced to reflect the work. The session wraps with audience questions.

Topics Covered

The Olympic shooter analogy: precision aimed at the wrong target
History of heat pumps, the 1970s energy crisis, and early marketing hype
Why heat pumps shouldn’t be treated as a silver bullet, and the “silver buckshot” approach
HVAC equipment versus the HVAC system
Installation performance benchmarks: roughly 57% for average work, about 6% more for code-approved work, and a goal of 88% or better
The three E’s: engagement, education, and expectations, plus measured results
The craftsmanship receipt and verification: “if you don’t test, you’re just guessing”
Setting customer expectations, including cold-climate performance and defrost
Right-sizing and the pitfalls of oversized equipment, even with inverter technology
Testing for pressure, airflow, and temperature (PAT) and not inheriting bad ductwork
Building science basics: leakage, room pressures, blower doors, and thermal imaging
Using Socratic questions and plain language to involve the customer
Avoiding data overload and using tools like Measure Quick and the TrueFlow Grid
Following a process and getting paid for diagnostics, basic versus advanced retrofits
Learning from mistakes and changing company culture

This episode contains embedded sponsor messages from Refrigeration Technologies, Carrier, NAVAC, and Filtrete.

Resources

Purchase your tickets or learn more about the 8th Annual HVACR Training Symposium at https://hvacrschool.com/symposium.

Search Episodes

Deliver High Performance Heat Pump Retrofits w/ David Richardson

11/12/2026

Bryan Orr

Did You Actually Test Every Heat Strip – Short #311

11/10/2026

Bryan Orr

Uncovering the Root Causes of Commercial Refrigeration Failures

11/05/2026