I have a very old (>15 years) american standard shower rotary control with temperature readout. Must remove and replace. Cannot remove handle. Set screw hidden. Need instrutions.

LOad the set screw up with WD-40 and try to loosen it. See if you can wiggle the handle off, If I were doing this I would remove the handle and face plate. Then I would open up the wall behind the valve so I didn't have to tear up the tiles. That's how I'd remove and replace the valve, If the hole in the tile is too large for the new faceplate I would purchase a remodel plate (see image) and use that. Good luck, Tom

Thanks! Did spary lots of wd-40 up into the set screw hole last night. Will try to muscle the screw loose tonight after work.

If the set screw is still stuck simply drill it out. Good luck, Tom