In a Williams in-floor furnace, it takes a thermopile millivolt (no
external electrical supply) gas valve numbered B67RA247 General
Controls with 1/2 inch fittings. I can't find an exact replacement. Is
there a universal one I can use? Where do I order it from? Is there
another one someone can suggest?

Ideally, someone could point me to a local supplier in Kansas City,
Kansas (or Missouri).

While watching the burner trays going well, they went off (the
thermostat was all the way up, and didn't turn off). I hit the gas
valve and the burner trays went on again. Also the pilot light button
has to be held a long time for it to remain on after releasing the
button. And also, sometimes I discover the furnace went off, pilot
light and all.

I already replaced the thermopile.

So, I see the next step as replacing the gas valve.

Here's a page that explains these things
http://www.diychatroom.com/f98/how-d...roblems-37230/

~ Nehmo