Exactly what is the most basic central heating loop?

I want to install a stove with a back boiler in my kitchen, I also want to heat up 3 or 4 rads in the upper floor form it. Somone told me I can do this without a pump or a header tank. Just 2 flow and return pipes, radiators, the stove and back boiler. Is this correct? Im not sure I believe it. Thanks