A good tip from Mr. Rooter in Pittsburgh:
This type of faucet head has evolved quite a bit over the years. Older models had a large heavy brass check valve in the line (to keep water from flowing backward) and these would chatter. If the pull-out chatters, replace it.
Newer models feature a check valve made as a small plastic one-way button in the bottom of the handle. All pull-out models work the same: Leave the head in place as a spout or pull it out and use its push-button as a sprayer. Like all sprayers, they sometimes have to be cleaned.
Start by pulling out the sprayer, unscrewing it from its hose, and setting it on the counter.
Tip #1 Using the counter-top for leverage, unscrew the screen with an adjustable wrench, if there aren’t flats for an adjustable wrench on the side of the screen, use pliers. (Wrap electrical tape several times around the jaws to avoid damaging the aerator.)
Tip #2 There are only two places to clean-the aerator screen and the check valve on the hose end. Check for debris in the screen and clean it out if necessary.
Tip #3 The hose end of the sprayer should have a check valve, a small plastic spring-loaded button. Use a needle and pick to see if it pushes in and out without hanging up on sediment.
Tip #4 It should work fine as long as you have the debris cleared from it. It it needs cleaning, use a cotton swab.
OR . . . Just call me at 615-306-0375 and I’ll do it for you!