Question for someone with more knowledge then me.
1993 home has a Trane heat pump at exterior.
Furnace is gas Trane brand also 1993.
Thermostat has no emergency heat mode.
My question is about the heat pump mode and configuration.
How does the exterior electrical, heat pump box near interior components function? Had power when I opened small box for heat pump.
It appears to be a gas furnace with an electric AC unit but I could not tell if the Heat pump mode operated or was functional.
How does the system know how to switch from gas, electric heat pump mode if no emergency heat function at the thermostat.
I could use some explaining, education on this one.
Thanks, see pics.