How To Add Valves Under The Sink

When it comes to plumbing repairs, valves are your friend. If you have a valve under the toilet, for instance, you don't have to find the main shut-off, which is often in the deep recesses of a crawlspace. Instead, you can turn off the water supply to the toilet, swap out the fixture, and turn it back on.

If you don't have a valve, by all means, add one when you're working on it!!

I'm working on a short kitchen project right now where I'll be adding a dishwasher and garbage disposal to an older kitchen. There are no valves in the kitchen, so adding some was the first step of my project. It's fairly basic, but that doesn't make it easy.

Often older homes have galvanized lines that corrode enough to make it hard to work with, but not quite enough to replace all of it. Here are some hints:

1. Turn off the water somewhere, usually the home's main water shut-off valve. If it's in the back of a crawlspace, it may be easier to shut if off at the street if it's easily accessible. Once the water is off, turn on a fixture in the lowest part of the home to drain as much of the water out of the system as possible. No use making any more mess than needed, right?

2. Disconnect the current supply lines- under the sink, in my case. If they are stuck, you might try using a little WD-40 to loosen them up.

3. Connect your valve. That's sometimes easier said than done. The valve section at Home Depot must have at least two dozen different types of valves. Which one do you need? Here's a starting point for you- most of the time, the hot/cold supply lines under the sink are 1/2" galvanized. The means you want a valve with one end labeled 1/2" FIP. This stands for "Female Iron Pipe because the valve will be threaded inside to receive the male end of the pipe that's under the sink.

The faucet connector after the valve can be tricky. If it's newer, it's most likely a 3/8" compression fitting. These are, by far, the most common for new fixtures. However if you're adding a valve you've probably got the original supply lines which could be any number of things. If you're unsure what it is, just take all the parts to the home store with you and get whatever fittings are needed to put it back together.

The iron pipe side is usually connected with Teflon tape or pipe dope, which is a gooey form of pipe thread sealant that you can 'paint' on the threads. Compression fittings don't need Teflon sealant.

4. Test and fix any drips. Drips happen. Usually it's a matter of tightening up your connections or redoing it with more sealant.

NOTE ABOUT DISHWASHER CONNECTIONS

You'll see that I chose a dual outlet valve for this project. That allows me to connect the water line as well as the dishwasher to this one valve. Quite handy, eh? I've put a cap on it for now because I haven't got the dishwasher installed quite yet.

When in doubt, call a plumber... :)

-Peter

www.CarpentryGuy.com