I'm trying to install an ecobee 4 thermostat, I have a dual transformer HVAC system, the HoneyWell Oil burner has internal voltage (approx 24VAC) and a Fan Control Center (https://hvacbasics.com/fan-center-control/) (that can be regarded as an external 24VAC adapter) I put together a diagram using draw dot io ,
screen_originalecobee.png
Then someone on a DIY forum helped correcting it ,
Ecobee_Diagram.drawio.png
I needed a second opinion do these look right? and don't smart thermostats have an internal jumping mechanism when needed between Rc and Rh? would that red jumper in the corrected diagram still be needed? thanks in advance
I have this type of setup on my home system as I'm on oil and have a/c. Only difference is I'm using a Nest instead of an Ecobee. It's still the same wiring for your scenario. You're basically using the fan center 24v as your primary 24v to power and control everything. You are simply adding in a small 24v relay to close a normally set of open contacts to finish the circuit to your furnace oil burner for when you have a call for heat. The second picture from the DIY forum is correct. It simplifies it the best and doesn't leave any window of conflict with both 24v voltages being at the stat. You will not need to jumper the Rh or Rc together. Just connect the R to Rc on the Ecobee and once you start up the stat, it will guide you through your connections and it will automatically know you're using the Rc as both the Rc and Rh.