Woodfired Boiler with Thumper Keg Storage.

I have a homemade boiler that burns pellets pretty cleanly.
It uses a TLUD (Top Lit UpDraft) stove to do this.
It is sitting, unfinished, in my unfinished greenhouse, waiting for me to get back to it.
I was planning on using thermosiphoning to circulate the water between the boiler tank and the storage tanks, but the tanks are all on the  the same level.
It occured to me , not for the first time, that steam moves on its own.
So the idea would be to connect the boiler to the first storage tank like so:



Instead of the thumper keg leading to a condenser, it would lead to another thumper keg, and that keg would tie back into the boiler.

The question is, can this work in a low/no pressure system?
Obviously the steam will need to exert force to overcome the weight of the water, but if the outlet is only a few inches deep, it might not amount to much.
Honestly, circulation pumps are cheap and can even be off grid, but this idea tickles my fancy.