i wonder how to install a trap primer after the fact. Good to know all about them, though.
junejulie, your questions can only be answered fully if everybody knows the height issues. Down to the 32nds of an inch. Either you take a picture and post it or send it to someone who will resize it and post it, or you describe very accurately what the situation is. How thick is the new tile, is it going on top of the old floor or are you ripping out the old tiles, etc. Is the current floor drain cover too high, too low or just right?
While you are at it, tell us if you want to change the drain cover look.
You can always leave the drain cover as is, and let it be "sunken" among the new tiles. You can even have a couple new tiles cut just right so that they fit it over like a cap, without grout. Then, when you want, you life that cap and let your washed floor drain into it. Cut two, to have one as a spare cap.
It is easy to devise other ways to prevent a floor drain from drying out too.
more later. bye for now. I hope your floor tiles are porcelain not "ceramic".
david