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Tech Tips:

This tech tip is the first in a four-part series on using oscilloscopes. I'd like to give a special thanks to Andrew Holden for his contributions to this particular tech tip. When we want to measure voltage between two points, we reach for a multimeter. A multimeter can tell us the average electrical potential between […]

Estimating Made Easy with Unity Build

Many of you may already know that our HVAC company, Kalos Services, is also a GC. We do a lot of construction projects with HVAC, plumbing, and electrical scopes of work. Estimating is a crucial part of winning those projects, and those of you who work on HVAC for new construction probably already have an […]

Buck-Boost Transformers

HVAC systems often fail early or don't perform well due to inconsistent power. While technicians can't control a home's main power supply, they can stabilize it at the system using buck-boost transformers. These devices adjust voltage up or down to meet the equipment’s needs. As HVAC systems become more advanced, understanding buck-boost transformers will be […]

Switch Terms

A while back, I had a tech who was having some trouble finding a 35 PSI (2.41 bar) make-on-fall pressure switch. One adjustable switch in the catalog said (SPDT), but he didn't quite understand what that meant. In that case, it means single-pole, double-throw, and the “double-throw” part means that the switch has terminals in both the […]

Discovering Mental Reference Points

Trying to wrap your head around HVAC can feel like a constant firehose of new info, right? Whether you're in class or on the job, there's just so much to soak up. And when you finally think you've got one thing down, BAM, here comes another concept. For me, remembering everything can be a real […]

Short Circuits

The term “short” has become a meaningless phrase in common culture to mean “anything wrong with an electrical device.” In reality, a short circuits refer to a particular fault that can mean one of two things in technical lingo: 1. Any two circuits that are connecting in an undesigned manner. This issue would be the […]

Understand Heat Pumps

My goal in this tech tip is to help those who struggle to understand heat pumps get their heads around them as quickly as possible and understand some of the things a tech needs to know about them. The basic idea of a heat pump is to use the compression refrigeration cycle to move heat […]

Isolation Diagnosis

There are many great diagnostic tools available to the service technician today, but I haven't found a tool as versatile as the simple isolation diagnosis. There are many ways this concept can be applied, but let's start with some examples so that you get what I mean. Low Voltage Short Circuit Isolation Diagnosis You arrive […]

Michael Faraday: Patron Saint of HVAC Technicians

Who was Michael Faraday—besides the guy we named the capacitor after? Well, actually, we named the measure of capacitance after him (the farad), but let’s not get all caught up in semantics. Faraday was a scientist who lived from 1791 to 1867. He was an experimental scientist who had little to no formal education but […]

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Podcasts:

What Is Up With Blower Amps & Watts w/ Steve Rogers

Bryan Orr and Steve Rogers dive deep into measuring power consumption in HVAC blower motors, particularly focusing on the differences between PSC (Permanent Split Capacitor) and ECM (Electronically Commutated Motor) technologies. The discussion stems from a question raised at an educators' conference about the accuracy of clamp-on meters in measuring blower motor watt draw, […]

Residential & Rack Startup and Commissioning (Part 1)

In this episode of the HVAC podcast, Bryan and Max Johnson from Kalos discuss the critical role of a startup and commissioning technician in the HVAC industry. Max, who has experience in both residential and commercial HVAC, shares his insights on the importance of understanding the scope of work, equipment specifications, and code requirements. […]

History of AWG – Short #186

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, […]

Analog vs. Digital Sine – Short #179

In this short podcast, Bryan breaks down the differences between analog and digital sine waves. Analog readings deal with an unlimited number of values; they are very precise and can have any number of decimals. As a result, the alternating current (AC) analog sine readings have very smooth curves when we read them on […]

Wiring Refrigerated Cases w/ Nathan & Phil

Phil Barr and Nathan Orr join the podcast to talk about wiring refrigerated cases in commercial spaces, including convenience stores and supermarkets. Cases may be medium-temp (or high-temp, in some cases) or low-temp. Medium-temp cases can typically defrost on their own during the off cycle, and low-temp cases may have electric or hot-gas defrost […]

Grounding and Bonding Myths Podcast

In this podcast episode, Bryan talks about grounding and some common misunderstandings related to ground, neutral, ground rods, and lightning. The common phrase that “current goes to ground” is a myth. The transformer (or the power source) that feeds a building creates a potential difference in charges (voltage); current is the motion of electrons between […]

High Voltage A/C Electrical Class

This podcast is a high voltage A/C electrical class that Bryan gave to some of the Kalos apprentices. The high voltage journey begins with basic electrical theory. Basically, a difference in charge is needed for electrons to move and generate power. Motors, which are inductive loads, are the greatest users of power that we will […]

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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.

In this episode, recorded live at AHR Expo 2026, Bryan sits down with Louise from UEi Test Instruments for an in-depth conversation about one of the most underestimated dangers in the HVAC trade: carbon monoxide. Rather than treating CO as just another checkmark on a safety list, Bryan and Louise dive into the full history of the gas — all the way back to early publications from 1922 and 1923 that were already studying the effects of low-level CO exposure. One of the most fascinating takeaways from their discussion is just how long the industry has known about the dangers of carbon monoxide, yet how frequently it remains misunderstood, misdiagnosed, and overlooked on the job site.

Louise breaks down the science behind CO poisoning in a way that is both accessible and eye-opening. Unlike high-level acute poisoning — where symptoms are immediately obvious — low-level, chronic carbon monoxide exposure is an entirely different beast. It can mimic the flu, chronic headaches, early-onset Alzheimer’s, and even heart attack symptoms. Because CO is colorless, odorless, and tasteless, it is notoriously difficult to diagnose, and victims often have no idea what is causing their illness. Compounding the problem is the cumulative nature of CO toxicity: the gas builds up in the bloodstream over time and can linger in the body for days, months, or even years after exposure ends. Bryan draws an entertaining but sobering historical connection between the prevalence of carbon monoxide poisoning during the Victorian era — when gas lamps were common inside homes — and the widespread reports of ghost sightings, fugue states, fainting spells, and the spiritualist movement of the time. It was almost certainly CO poisoning, not the paranormal.

The conversation then shifts to practical, on-the-job guidance for technicians and contractors. Bryan and Louise walk through the proper process for combustion analysis: starting your analyzer outside in fresh air, identifying test ports on furnaces, boilers, and water heaters, and understanding what readings at steady state actually mean. They emphasize that CO production is not limited to furnaces alone — ranges, ovens, dryers, fireplaces, water heaters, and even propane-powered forklifts are all legitimate sources. One of the most critical points they make is that carbon monoxide hazards are often intermittent and condition-dependent. A system can appear to be working perfectly during one visit and be producing dangerous levels the next time a door is closed or a vent is accidentally blocked. Visual inspection, awareness of combustion air sourcing, and thoughtful analysis are just as important as having the right instruments.

On the product side, Louise introduces two exciting new offerings from UEI. The first is the UEI Clip, a compact personal CO detector that clips onto a bag, belt, or lanyard, activates automatically at 20 ppm, and is designed as a set-it-and-forget-it safety device with a two-year sealed battery lifespan. Priced under $100, it is an affordable way to outfit an entire team with a baseline layer of personal protection. The second highlight is the new High Accuracy Clamp Meter (HAC), a commemorative product celebrating the United States’ 250th anniversary. This meter excels at wattage measurement — particularly with low-draw ECM blower motors where most meters fall short — and Bluetooth integration with MeasureQuick is on the horizon. Louise also walks through UEI’s revamped combustion analyzer recertification program, UEI Service Plus, which offers same-day turnaround on standard recertifications at their Indianapolis facility, extended warranties with each annual service, and transparent, upfront pricing directly on their website.

Topics Covered

The history of carbon monoxide research dating back to publications from 1922 and 1923, and a 1923 patent for a hot water heater that sparked a friendly debate between Bryan and Louise about terminology.
How low-level, chronic CO exposure is underdiagnosed and can mimic conditions like the flu, chronic headaches, early-onset Alzheimer’s, and heart attack symptoms — and why CO builds up cumulatively in the bloodstream.
The fascinating historical theory connecting widespread Victorian-era reports of ghosts, fugue states, and fainting spells to chronic carbon monoxide poisoning from indoor gas lamps.
CO safety thresholds: residential standard (9 ppm), World Health Organization guideline (4 ppm), first responder evacuation threshold (35 ppm), and how UL-rated home alarms may not trigger until 70 ppm sustained for 1–4 hours.
Sources of CO that technicians often overlook, including ovens, ranges, dryers, fireplaces, water heaters, propane forklifts, generators, and vehicles idling near garages.
Proper combustion analysis procedure: starting the analyzer outside in ambient air, identifying or installing test ports, running tests at steady state, and interpreting O2, CO, and stack temperature readings.
Industry CO standards for furnaces: official standard (400 ppm), HRI recommendation (200 ppm), industry best practice (100 ppm), and modern high-efficiency benchmarks (50 ppm or less).
How combustion air sourcing — and changes to it (new roofs, blocked vents, swapped doors) — is one of the most commonly missed risk factors for CO production.
Why even “heat pump markets” like Florida still need combustion analysis, since over 90% of homes have at least one fuel-fired appliance.
Introduction of the UEi Clip personal CO detector: set-and-forget, activates at 20 ppm, sealed 2-year battery, priced under $100, and its unexpected popularity among refrigeration technicians.
Introduction of the UEi High Accuracy Clamp Meter (HAC) commemorative edition: exceptional accuracy at low current draws (ideal for ECM blower motors), full accessory kit included, and upcoming measureQuick Bluetooth integration.
UEi’s Service+ combustion analyzer recertification program: same-day turnaround at their Indianapolis lab, extended warranty with each annual service, prepaid UPS shipping labels, and transparent pricing on their website.
A brief spotlight on UEi as a family-owned business founded by Michael Kane’s parents, with their own manufacturing operations in the UK and Korea.

Learn more about UEi’s new and longstanding products, as well as the Service+ guarantee, at https://ueitest.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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Search Episodes

Don’t Die! w/ Louise from UEi

02/26/2026

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Heat Exchanger Crack Comment – Short #280

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