The home I moved into has a Honeywell thermostat controlling an Amana heat pump. I am trying to replace this with a Nest thermostat instead. Here is a photo of the wiring for the existing thermostat before making any changes:
Nest wants me to identify both of the "Y" wires. How can I tell which one controls heat and which one controls cooling?
I'm also unsure how I can determine whether the heat pump should be set up for "O" or "B", though I've read that most are "O". Will I cause damage to the equipment if I set this in the wrong mode?
Which wire is used for emergency heat via the heating coils? Is that the W2 wire in the image above?