I've gotten good answers here before, but I haven't posted in a long time.
This one should be easy -- We installed a Delta combination kitchen faucet/sprayer a while back, and for months it worked perfectly. When I used the sprayer, the tap would stop completely and divert the flow entirely to the sprayer.
Not any more; now the tap stays on at reduced flow and the force of the sprayer is much less.
Can someone tell me what caused the change in the way the Delta works and how I can fix it? It has to be a problem nearly everyone experienced sometime.