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#subcritical

Tech Tips:

Ramping Your Team Up for CO2

This tech tip is based on a podcast with Andre Patenaude from Copeland. You can listen to that podcast episode HERE, and we encourage you to check out some of the resources at the end of this tech tip—whether you’re all in on ramping your team up for CO2 or just CO2-curious. Carbon dioxide (CO2) […]

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Our latest Podcast

HVAC School – For Techs, By Techs

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.

Mastering Your Meter Advanced Functionality with Louise Kellar (UEi Test Instruments)

byBryan Orr

In this episode, Bryan welcomes back Louise Kellar of UEi Test Instruments for a deep dive into getting more out of a digital clamp meter than the basic volts, amps, and ohms most techs rely on every day. The tool in the spotlight is UEi’s High Accuracy Clamp Meter (HAC), which is accurate when dealing with the low current draws common on modern condenser fan and blower motors and is critical for reliable wattage and capacitor-under-load testing.

The podcast also walks through a series of lesser-used but valuable meter functions, including microamp measurement for flame rectification testing, diode testing for diagnosing boards on mini-splits, the Low Z setting for eliminating ghost voltage readings and safely bleeding capacitors, and the safety-locking temperature toggle that prevents technicians from accidentally crossing voltage and thermocouple leads.

Bryan and Louise also cover common mistakes, such as not knowing when to use continuity or resistance and auto-ranging mistakes, as well as some crucial takeaways about true RMS measurements, temperature settings, and CAT safety ratings.

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

Resources

UEi products, manuals, and resources
HVAC Multimeter Skills: Continuity vs. Resistance & Diode Testing (video)
CAT Ratings on Electrical Multimeters (tech tip)
HVAC School calculators
Submit a podcast question
Learn about the GRIT Foundation

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

Mastering Your Meter Advanced Functionality with Louise Kellar (UEi Test Instruments)

Search Episodes

Mastering Your Meter Advanced Functionality with Louise Kellar (UEi Test Instruments)

09/17/2026

Bryan Orr

Premature Coil Failure in Ductless Mini-Splits & VRF Equipment – Short #303

09/15/2026

Bryan Orr

Advanced Refrigerant Recovery: Best Practices for Diverse Systems and Environments

09/10/2026

Bryan Orr

The A2L & Refrigerant Transition – Short #302

09/08/2026

Bryan Orr

Invented For Techs, by Techs: Inside Refrigeration Technologies’ “The Lab”

09/03/2026

Bryan Orr

The Ethics of IAQ – Testing vs. Remediation Conflicts – Short #301

09/01/2026

Bryan Orr

Is 400 CFM per Ton Always Right? w/ Ty

08/27/2026

Bryan Orr

The MERV 15 Filtration Physics – Short #300

08/25/2026

Bryan Orr

Tips for Being On Call w/ Ty

08/20/2026

Bryan Orr

The Florida “M-Word” – Legal Boundaries & Tech Communication – Short #299

08/18/2026

Bryan Orr - A/C Trainer

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Check our latest Tech Tips

The Basic Residential Maintenance for a Heat Pump / Electric System Technician Head Trash Why the New Guy Gets Fewer Callbacks

VIPER SNIPER UNIVERSAL AEROSOL TRIGGER SPRAYER

VIPER SNIPER UNIVERSAL AEROSOL TRIGGER SPRAYER The Viper Sniper is an ergonomic trigger sprayer that fits all standard aerosol cans. Designed for comfort and control, it reduces finger fatigue and delivers a smooth, consistent spray, especially in those hard-to-reach areas. Features quick-attach side clips for easy, secure use. Compatible with all standard aerosol cans —including Viper Aerosol Coil Cleaner and Coil Coating Spray. Fits Any Aerosol Can Full Hand Ergonomic Grip Easily Clips On and Off 2 Sprayers per pack

VENOM PACK CONDENSER PURE CONCENTRATE COIL CLEANER

VENOM PACK CONDENSER PURE CONCENTRATE COIL CLEANER Venom Pack Condenser Cleaner is a high foaming pure concentrate liquid designed to tackle the toughest soils. The proprietary blend of specialty detergents will liquify heavily embedded grease and grime to restore heat transfer and increase the efficiency of the coil.

Viper Condensate Pan and Drain Treatment

Viper Condensate Pan and Drain Treatment Viper Condensate Pan and Drain Treatment is a sprayable gel. It coats the pan, p-trap and drain piping with a lubricative film to improve flow and prevent future soil adhesion. The slow dissolving enzyme gel will outperform and outlast conventional tablets and strips.

Nylog Blue Gasket -Thread Sealant for AC/R Systems

Nylog Blue Gasket -Thread Sealant for AC/R Systems One drop of Nylog on your rubber hose gaskets prior to attaching your core tools, hoses or vacuum gauge will assure that things do not bind or leak during evacuation. Derived from refrigeration grade lubricants. Non-hardening, non-drying fluid which bonds tenaciously to many different substrates. Typically, one drop of Nylog can be stretched about three feet before breaking.

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