Do you need an aquastat when adding scavenger loop to steam boiler

I want to add approx 20' of baseboard off a steam boiler. I want to be able to control it independentaly from the steam. I know about the flow controls, by-pass, thermometer and bronze circulator. But don't I need an aquastat to fire the boiler if boiler isn't running for the steam?
Is there any other circ, other than bronze B&G 100?