Hot water.
Valve from a solar energy system that produced hot water?
Nope.
Commercial solar thermal valve
Valve from a hot water recirculating system
Hint: The name of it, which has the initials C.S.T. came from the fact that back in the day (I’m old school) we used to build this component out of common fittings.
steam trap
common steam trap
Roy, you are in Florida. You’ll probably never see one of these down there. That’s another hint BTW.
Is this for a one pipe heating system that lets the steam out and water in the return.
Nope.
It goes on a boiler I think , But I don’t know the name .
It is magical. It has no controls or moving parts yet it does its job as if there were.
I have a feeling I’m in same boat 
Tim, I’ve seen them in Southern California on commercial buildings.
It’s a baffle or diverter?
“Concentric Sediment Trap”
Another hint: Although there is a valve on it (I’m holding it by the valve handle in the PIC in post #1)… the 4 inlets/outlets are all open to each other when in operation (valve in open position). It’s basically an intersection where the water seems to know to go in the right direction and amount when it comes to the intersection. Like I said, they are magical devices IMHO, and so simple.
“Wife away from home device”
I’ve always wanted one of those .
Copperfield steam tee?
Not a sediment trap I’m guessing either.
Hot water or steam?