Indirect Soldering Technique
As HVAC/R techs, we don't generally do a lot of soldering—unless you are in a shop that has embraced Stay Brite® 8 from Harris. Several aluminum repair products on the market also use an indirect soldering type technique, so this is a generic overview of some best practices. As always, follow the manufacturer's instructions for […]
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Does Air or Nitrogen Absorb Water?
There are many examples of teaching using metaphors to help someone grasp how something works without being EXACTLY correct. Some examples are how we often use water flow to explain electrical flow or refrigerant circuit dynamics. It's enough like the way it works to get our heads wrapped around it, but there are many differences. […]
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Why A/C Systems Freeze
Let's start with the basics. Water freezes at 32° Fahrenheit (0° Celsius) at sea level and at atmospheric pressure. When any surface is below that temperature, and the air around it contains moisture, ice/frost will form. You can see how water freezes at the molecular level in the GIF below:   In some situations, ice […]
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Living in a World of Acids (and why HVAC coils are secretly crying for help)
Imagine a small IT room packed with servers, monitors, and humans. CO₂ levels easily spike to over 3000 PPM since the room lacks fresh air ventilation. Two overworked mini-split units churn away, cooling the space and unknowingly creating the perfect acidic environment. Fast forward a few months, and those shiny coils now resemble something pulled […]
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HVAC/R Refrigerant Cycle Basics
This is a basic overview of the HVAC/R refrigerant cycle (and refrigeration circuit) and how it works. It isn't a COMPLETE description by any means, but it is designed to assist a new technician or HVAC/R apprentice in understanding the fundamentals. First, let's address some areas of possible confusion:  1. The word “condenser” can mean […]
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Shielded Control Cable & Communicating Controls
When I first started in the trade, we used to run into shielded control cable on the Carrier Comfort Zone 1 zoning systems and also on a Carrier VVT system I used to maintain at a bank. I knew it had something to do with electrical “noise” and that communicating systems often called for it, […]
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AHRI Ratings Are Not Design Conditions
I’ve been designing a system for a home here in Dallas and noticed a couple of interesting (and disturbing!) things about the equipment’s advertised capacity vs. the actual capacity at design conditions.  Equipment is rated at AHRI conditions (95 degrees outside and 80-degree dry bulb, 67-degree wet bulb inside). These conditions make equipment performance LOOK […]
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Valve Core Removal Tools
Valve core removal tools were originally developed to remove damaged valve cores without the need to pump the system down. This technology was a major leap forward in work efficiency, as pumping down a system can be a tedious and time-consuming task.   Eventually, technicians discovered that removing valve cores led to faster evacuation, recovery, and […]
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“White Shirt Techs – Manifesto” in Practice
I wanted to offer some practical advice from Bryan’s last podcast, “White Shirt Techs – Manifesto.” The link can be found HERE. In this episode, Bryan strongly (and rightfully) critiques sales tactics that are divorced from technical skills and meaningful benefits for homeowners.  As a one-man HVAC company, I wanted to offer a suggestion for […]
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