NATE Air Conditioning and Heat Pumps Practice Exam

Which terminal designation on the thermostat subbase typically is used for the cooling circuit?

1. G

2. R

3. W

4. Y

The correct answer is: Y

The terminal designation that is typically used for the cooling circuit on the thermostat subbase is represented by Y. In HVAC systems, the Y terminal connects to the compressor in the air conditioning system, activating the cooling function when the thermostat calls for cooling. By energizing the Y terminal, the thermostat signals the system to turn on the compressor and circulate refrigerant to provide cooling to the space. The other terminal designations have specific roles: R usually denotes the power supply from the transformer to the thermostat, W is used for the heating circuit (typically for a furnace), and G controls the fan operation. Understanding these designations is critical for troubleshooting and installation of HVAC systems, as they indicate how components communicate and operate within the system.