HVAC Low Voltage Control Wiring for Total Beginners

Fundamental principles and typical control wiring is covered from thermostats to control boards in most HVAC systems. Typical Low Voltage Control Circuit Schematic: https://i.postimg.cc/dQhn9SS4/LOW-VOLTAGE-CONTROL-CIRCUIT.png Control Circuit With Relay: https://i.postimg.cc/mrZy1dH3/control-circuit-open.png Comprehensive Furnace Wiring: https://youtu.be/7zdzgKAYJCU Comprehensive Heat Pump Wiring: https://youtu.be/F88Y9NkvtQw 00:00 Misconceptions 00:29 What Are We Controlling? 01:14 Basic Control Circuit Concept 02:53 Where Control Power Comes From 04:47 The "R Circuit" 06:13 The "Y Circuit" 09:51 The "G Circuit" 10:42 The "W Circuit" 12:17 The Common Terminal