Refrigerant 101: Glide, Blends & Why You Can't Mix Refrigerants

Ever wondered why techs get warned never to mix refrigerants — but nobody explains why? In this Refrigerant 101 session, TY Branaman breaks down blends, glide, and fractionation using real temperature/pressure charts so you can actually see what's happening inside the coil instead of just memorizing a rule. TY walks through the difference between 400-series zeotropic blends and 500-series azeotropic blends, why some refrigerants have near-zero glide while others have a huge one, and how MeasureQuick calculates superheat off the dew point instead of the midpoint saturation number most gauges show you. You'll also see a live glide calculation pulled straight from a pressure/temperature chart, plus a real-world discussion on spotting a contaminated or mixed-refrigerant system in the field — including why a sight glass can catch flashing that your gauges alone will miss. If you've ever had a system where your superheat and subcooling numbers "look fine" but something still feels off, this one's for you. What's covered: 400 vs 500 series refrigerants — what makes something a blend Glide explained: bubble point, dew point, and midpoint Why 438A has such a dramatic glide compared to 410A How fractionation happens as a blend boils off in the coil Why you must charge blended refrigerants as a liquid, not vapor MeasureQuick's superheat calculation vs. midpoint saturation Live glide calculation walkthrough on R454B Real signs of a mixed or contaminated refrigerant system Using a sight glass to catch flashing and confirm subcooled liquid Why oil return matters in blends like R410A and R454B Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/ or the HVAC School Mobile App on the Google Play Store (https://hvacrschool.com/play-store) or App Store (https://hvacrschool.com/app-store).