Schematics come to life through all modes & sequences of a heat pump, which is absolutely necessary to know in order to successfully troubleshoot and fix conventional heat pump systems.

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00:00 Thermostat, AH & CU External Wiring
02:13 CU/Defrost Control Board Cooling Mode
04:44 CU High Voltage Circuits
06:11 Low Voltage System Heating Mode
06:57 Defrost Cycles
12:45 Auxiliary & Emergency Heat