My kitchen faucet has some sort of shuttle valve that operates when you use the separate sprayer.
I hear it make a knocking sound like a steel ball bearing in a metal chamber.
Occasionally it will knock and no water will come out of either of them.
In that case I simply shut off the faucet and all goes back to normal .
I reported this to the manufacturer and they sold (grrrrrr) me a part.
This issue was so critically important that the new part still sits on my workbench two years later.
