Hi. I am planning to install new kitchen faucet and noticed that there are two shut off valves under the sink. One of them is badly rusted and needs to be replaced. I noticed that it is connected to three pipes (one of which is kitchen faucet). The other is clearly water coming in. What is the third one connected to wall? Also how should I go about replacing this? Anything that I should be careful of?
Double Shut Off Valve Dishwasher
make a drawing of what you have. . .take it to Home Depot or better yet, a plumbing suppy place. They will be able to replace what you have. Just replace what you have and it will work. The interesting thing about shutoff valves is that they are always broken when you need them and work when you don't. They last no longer than what you are protecting. Buy the best ones they have. I have a strange one that is connected to three pipes. . .the water comes in one and goes out to the faucet and the dishwasher. . .three pipes. That's the hot water. And then the cold water comes in and goes up to the faucet. .the second shutoff.
it looks like a 1/2 inch galvanized pipe out of the wall, and the valve is screwed on to it. kinda hard to see the back side of the valve and pipe. it could be a 1/2 inch copper pipe and the valve could be a compression type. anyway, you will have to cut the water off unless this is the hot line in and if so you can cut the water off at the water heater. its probably a cold line in and obviously you cant take the valve off without cutting off the main supply line some where. take off the two small lines and don't move them around to much, they are compression fittings so just reattach them to the new valve. then unscrew the valve, you may have to hold the incoming pipe but just try the valve first. take the valve to a plumbing supply, Lowe's, or home depot and get one just like it. if one place doesn't have it go to another and find the same valve. if it screws on get a small tube of pipe dope to coat the threads. if you anticipate problems get a 1/2 inch galvanized cap [if that is the pipe you have coming out of the wall] so you can plug the pipe and cut the water back on temporally. this is general info so you will have to deal with your special situation. good luck.
You have to shut the main water supply off when you change the valve. It will either have a compression fitting or female threads on the part that connects to the water inlet from the wall. Make sure you get the right type. Use two wrenches when you change it. The extra line is probably for a dishwasher. Dishwashers do not have their own water supply lines. Hope this helps. Gerry Barr
In most installations, its the pipe that comes OUT of the wall, that is the supply line. On old enough faucets, a sprayer could have been attached by connecting it to one side or another (usually the hot water line) A dishwasher would also be connected to one or the other shut - off valves, which would depend on the model of dishwasher. You didn't mention, do you have an instant 'tankless' hot water heater under the cabinet? If so, then yes, your water supply may be coming from it, rather than the wall.... in which case, I'd suspect there was another sink (bathroom?) on the other side of that wall, being fed by the same tankless heater. This would NOT be the normal way to connect a tankless heater....but you wouldn't believe some of the things I've seen over the years, lol. And of course, if your refrigerator has an ice maker, and/or water supply in its door, you'll have a line running to the cold water supply for it.... but it may or may not be under the sink. Often, it gets run right through the floor and connected to the cold water line there. We can't really see enough of the lines to tell where they are going to give a definitive answer. Feel free to email or post more pics of all the lines, and I'll check back later, or you can email me. If both shut-off valves are corroded any at all, I'd go ahead and replace both of them, while I was working under there. Have Fun
