I replaced my shower cartridge valve (Kohler Rite Temp Kit 76851) recently because of dripping. When I took the old cartridge out, I saw a few small pebbles in the hot water pipe in the wall, about 0.25" in size and removed them and flushed the pipe for several seconds before putting the new Kohler cartridge in. It worked fine for 3 days with no dripping. Then suddenly and spontaneously, water is coming out of the shower head forcefully as if I turned it on, except it is in the off position. I had to turn the water main valve off, took the cartridge out, found 2 more small pebbles at the hot water pipe in the wall, removed them and flushed the pipe again. The cartridge looked fine with no grinding and as far as I can tell, there is no pebble in the cartridge. I replaced the cartridge, everything seemed fine for 2 days and then it happened again with water suddenly spurting out of the shower head spontaneously.

Is it a defective Kohler cartridge? Something wrong with my installation? The pebbles causing this? Please help.
Chuong

Start by turning off the water and check to see if the Shower Valve Core is seated properly. You can then try a new Cartridge, they can be defective.

Reference

We will discuss this farther. I would prefer discussing this out in the open so all the experts can chime in instead of PM's. Thanks, Tom