Attention, kilted amateur plumbers!

[dfmacliam]

sounds like the valve is not opening... you have one handle for hot and cold?

Checking the Diverter Valve

Uneven water flow, low pressure when the pressure at other faucets seems all right, or troublesome switching back and forth from spray head to sink spout can be caused by a malfunctioning diverter valve or by a restricted hose. To check the diverter valve:

Step 1: Remove spray head at coupling, and disconnect coupling from hose by prying off snap-ring retainer.

Step 2: Turn on water and let strong stream of water flow into hose. If strong stream of water flows out of open end of hose, then you know diverter valve is the source of the trouble. A weak stream flowing from open end of hose may indicate blockage in hose itself. Briefly running water full force may clear hose.

Step 3: If above steps don't locate problem, remove hose from spout attachment, stretch it out straight, and look through it while aiming it toward strong light source. If hose appears to be clear, problem lies in diverter valve. If hose is blocked, clear it with wire coat hanger or length of wire.

Step 4: As needed, replace hose. If you can't get exact replacement, adapters are available for connecting other types and sizes.

Servicing the Diverter Valve

Step 1: Remove sink spout by loosening screw on top, unscrewing threaded spout ring or nut, and lifting spout out of its socket to expose valve. Some valves are just set in place and can be lifted straight out by gripping them with pliers; others are secured by screw. If there is a screw, turn it enough to free valve. If possible, disassemble valve.

Step 2: Flush all parts with water, and clean all surfaces and apertures with toothpicks. Don't use metal tools, as they could damage the unit.

Step 3: Reassemble and reinstall valve, then test unit. If it still operates poorly, you will probably have to replace valve. Replacement must be exact, so take faucet manufacturer's name and unit model number or old valve with you when you buy new valve.

Whether it's a spray hose or a spout, your home's faucet system will need periodic repairs. But if you follow the steps we've outlined in this article, you'll be able to get these jobs done with minimal trouble.

this information came from ask.com