Mike PleziaInside service technician, Clark Associates · Commercial Equipment, HVAC, and Refrigeration professional

Superheat and Subcooling Tell the Story #HVACTips #Refrigeration #NewTech

14 Aug 2026 · 1 min

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In this brief instructional video, the speaker introduces two key refrigeration measurements—superheat and subcooling—as essential diagnostics for system health. Superheat is defined as the temperature rise of refrigerant vapor above its boiling point on the suction side, while subcooling is the temperature drop of liquid refrigerant below its condensing point. The speaker explains how low superheat may indicate a flooded evaporator and high superheat may signal low refrigerant charge or a restriction, and how subcooling reflects condenser performance. The core message encourages technicians to learn, trust, and act on these numbers before adjusting valves, emphasizing that the measurements tell the story of the system’s condition.

Chapters

Hey, are you new to the trades? Here's something you may not know about refrigeration fundamentals. 2 measurements will tell you more about a refrigeration system's health than almost anything else: superheat and subcooling. Superheat tells you how much the refrigerant vapor has been heated above its boiling point at the suction side. Subcooling tells you how much the liquid refrigerant has cooled below its condensing point. Superheat and subcooling tell the story. Low superheat could mean a flooded evaporator. High superheat could mean low charge or a restriction. Subcooling tells you if your condenser is doing its job. These numbers point you toward the problem before you ever touch a valve. Learn to read them. Learn to trust them. When the numbers speak, listen. Now that you know, you can help someone else know.