Hi, I'm hoping someone can help with a problem we are having? The kitchen sink has a mixer faucet (handle/tap each for hot and cold with a center mounted outlet pipe) and a sprayer attachment. The sprayer attachment is connected to a flexible hose that attaches to the middle, underside, of the faucet assembly. The problem started with this sprayer unit. My wife attempted to use it to rinse some dishes but no water flowed when she depressed the handle on the plastic sprayer attachment. Then water wouldn't flow from either hot and/or cold tap either. I eventually got a dribble of water to flow by opening the cold tap a little and running the washing machine and both baths! (I hope this doesn't sound crazy but it is what happened. I actually thought I had an air lock of some kind and was attempting to disrupt the blockage by reducing pressure. We live in an old condo and water pressure is severly affected by turning on one or more outlets.) The water flow from both hot and cold taps increased but only to approx. half the pressure that existed before she tried to use the spray unit. The situation has pretty much stabilised now but it is not back to normal. When you turn on hot or cold you can turn it on a little - there is some spitting - like gas trapped - then it flows pretty consistently. However, if you turn the hot or cold tap too much there is a 'klunk' noise from the faucet and water stops flowing. Turn off the tap and there is another 'klunk' sound. Turn it on again, slowly, and you have water. Does this sound like a valve of some kind is broken or worn, or do I need a new complete unit? Your help and advice would be appreciated. Thanks.