I'm after a float valve of some sort which will not get damaged if it is completely submerged. I want to have a tank which is mostly filled from local sources of water but, if the local sources dry up, then the float valve will maintain a foot or so of water in the bottom of the tank from the mains. (I guess there will have to be strict non-return precautions to conform to water byelaws too)
So, I need a float valve that won't mind being underwater, I suspect that the 'standard' sort of cold water tank valve with a big spherical float won't survive being under water.
Would a Torbeck valve be OK, or do they include the flushing mechanism which I don't need?