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Replacing a Dishwasher – How to Install Dishwasher Plumbing

December 22, 2014 By Chuck Harrison

All right, so today we’re going to look at dealing with replacing a dishwasher and the plumbing associated with it thanks to the pros at http://denverappliancemasters.com. I disconnected the old dishwasher, I disconnected the hose and the water supply going into the shut off valve and the next thing, we have a flexible conduit, going to a little electrical box, inside the dishwasher itself and all I have to do is unscrew these two wire nuts and then the nut that’s holding the fitting onto the conduit and that will allow us to pull the old dishwasher out of here.

So we have the new dishwasher and I am going to go through the steps to install it. I am going to connect the electric first and on the bottom of the dishwasher, on one side you are going to find the electrical box, we’re going to remove the cover and you are going to have a white and a black wire. The white is your neutral, the black is your hot and in this case, we’ve got flexible metal conduit that I am going to connect.

So I am going to push this through the back of the box and I am going to connect it with a metal nut and then I am going to connect the black wire to the black wire and tighten it down with wire nut. It’s very important that you connect black to black, white to white. And always shut off the electric on any circuit you are working on. In this case I turned off the breaker and I tested the wires before I started. So I’ll tighten this down and then we are going to the next step.

The next step, I am going to connect my water supply and for the water inlet, in dishwashers you are going to have two different fittings that you can use. In some of the newer dishwashers, you are going to have three quarter inch hose fitting connecting to a three eights compression. Three eights compression is going to fit to your supply line.

In this case, we have three eights iron pipe on one side which is going to go into this inlet and we have three eights compression on the other side to fit the supply line. And the supply line is going to be be connected to the valve. In this case, we have a double valve, so I have one of the hot going up to the sink and the other side of the hot is going to the dishwasher. If you are in a condo or somewhere where you didn’t want to take off the valve and change it to a double, this is a great little fitting you can get to a hardware store.

You’ve got three eights compression on one side, a female that’s going to connect to a valve and it’s going to give you two different threaded connections here, so you can go up to the sink and over to the dishwasher. So I’ll connect the supply line now and then we’ll move on to the next step. I put a hole to the bottom of the cabinet and that’s where the supply line is coming from the dishwasher and we’ll push this cabinet back and connect it to the valve.

And then we have the drain holes. I cut a hole up high, it needs to loop thirty-two inches off the ground for it to drain properly. And now this is going to be connected to the pipe going into the P trap. And this has to be above this connection, has to be above the J bend or the P trap, going into the wall. So this is how we’ll connect it, we’ll get a hose clamp and tighten this down and then we are going to connect all the under sink.

Before connecting the supply line on the new dishwasher…

Before you connect a new supply line to either your faucet or a dishwasher, you’d want to bleed it first. So I connected the supply line to the valve and I am just going to let it run for a couple of seconds. And if you had any debris build up, just from working and get caught in here, you don’t want it to get caught in the aerator, in the faucet or especially for the dishwasher, all the small pieces inside the dishwasher.

So it’s always a good idea to grab a bucket, bleed it first and especially if you have galvanized pipe and you shut off the water and you turn the main back on, just that activity shakes loose a lot of rust. So it’s always a good idea to bleed your valve before you are connecting a new supply line. I’ve cut my extension pipe to size and I am going to slip it up, I’ve got a nut in the washer above it and we’ll just snug that down.

Now I am going to take my trap, I’ve got a nut and a washer above it and we’ll just line it up to make sure everything is placed properly and in this case, we’ve got the dishwasher drain so this is what we are going to connect to it. I’ll cut this to the proper size and then we’ll put a hose clamp here.

If you didn’t have a drain washer, you would use just an extension pipe in it’s place and now I’ll go back, I’ll tighten all of the nuts, plastic going to the plastic thread, here I’ve got metal going up to metal and this stub out, that the main drain is going into is metal so I am using a metal nut here. And those are the steps to change the under sink drain pipe for a kitchen sink.

I’ve got the dishwasher in place and I leveled it and connected it with two brackets to the bottom of the counter. And this is what it looks like, it’s a direct connect to the under sink supply here. And there are two ways you would connect the drain hose, it would either be a direct connect, like this or you would connect it to a garbage disposal.

So just to recap, if you are taking out your old dishwasher, you want to turn off the electric first, you want to turn off the supply to the old dishwasher and disconnect the hose. You pull it out, double check your electric and then you would disconnect your electric and your water supply and the drain hose. And that’s all there is to it, to replace a dishwasher.

Here’s a bit more help, if you need it, courtesy of YouTube…

Filed Under: Appliances

Chuck Harrison

Chuck Harrison

I'm a California boy, through and through. I love the ocean and couldn't imagine living where I couldn't see it every day. Fortunately, my wife and kids have the same passion for it as I do. When I'm not doing things with my family, it's because I'm working. I'm also fortunate that I love what I do - everything that has to do with fixing up old properties and showing others how to do it themselves. I've even started my own website here to try to consolidate some of the knowledge I've gained over the years. It's a new(ish) but ongoing project. Lucky for me my kids are still around to help me with the techy stuff!

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