G terminal: Activates the blower fan to move air through the ducts. W2 and Y2: Secondary stages for extreme temperature demands.
Thermostat Wiring Secondary Stages Explained
Colors do not always indicate function, because a wire’s job is defined by the letter stamped on its terminal end, not by the plastic sleeve around it. O and B terminals: Control reversing valves on heat pumps, switching between heating and cooling modes.
Follow each wire back through the wall to the furnace or control board. Transformer Connections Explained Transformer leads: Typically attached to the T and R terminals on the equipment.
Understanding Thermostat Wiring Secondary Stages for Heat Pumps
For example, a heat pump might use W1 for the first stage of heating, W2 for a second stage with auxiliary heat, and Y1 and Y2 for staged cooling. Compare your findings to a generic thermostat wiring chart for your system type.
More About How thermostats are wired
Looking at How thermostats are wired from another angle can help expand the discussion and give readers a second clear paragraph under the same section.
More perspective on How thermostats are wired can make the topic easier to follow by connecting earlier points with a few simple takeaways.
