Google Nest Community

As a EE, I am fooling around testing my device using LEDs connected to the output pins (O, Y, G, W). When cooling switches on, O, Y, and G are energized, as expected. But when cooling shuts off, while Y and G are de-energized (as expected), but O rem...

I'm trying to install a Nest Thermostat E on my old dual-fuel (propane) heat pump. I'm confused about the W wire. I understand that it's used by the thermostat to call for auxiliary heat (if the outside temperature is too low or the set-point is much...