Replacing a Dishwasher

In this article, we’ll show you how to pull out your old dishwasher, slide in the new one, and make the new water, drain and electrical connections.

In most cases, you won’t need any special tools or skills to do a first-class job. Most dishwashers are 24 in. wide, so you won’t have to alter cabinets to get the new one to fit. (If you change sizes, you’ll have to alter your cabinets. This requires more advanced carpentry skills that we won’t show here.)

You may find that extra layers of flooring have raised the floor height in front of the old dishwasher. This can make it difficult to get the old dishwasher out and the new one in. In some cases, you have to either loosen the countertop or remove flooring. Consider consulting a professional installer if you don’t feel confident about the best strategy.

Before You Start
Get a blanket, an old rug or cardboard to protect your floor while you work. Gather two adjustable wrenches, a screwdriver, a tape measure, a pair of pliers and a level. You’ll also need a shallow pan, bucket, sponge and rag to collect water that’ll drain from the lines when you disconnect them.

Turn off the power to the dishwasher at the main panel or unplug it under the sink. Also turn off the water to the dishwasher at the nearest shutoff valve, usually the hot water shutoff under the sink. Or shut it off at the water heater.

Consider removing the cabinet doors from your sink base to make disconnecting the drain lines easier.

Disconnect the Electrical Cable and Water Line
The water and electrical connections are underneath the dishwasher, behind a lower front panel that you have to unscrew (Photo 1).Always test with a voltage detector ($2 to $12 at a home center or hardware store) to make sure the power is off. When you remove the electrical line from the box, leave the cable clamp on and reuse it on the new dishwasher (Photo 12). Sometimes dishwashers are plug-and-cord connected rather than “hard wired” as shown in our photos. If so, disconnect the cord and reuse it on the new dishwasher. If it’s in bad condition, buy a new one ($12) from an appliance dealer.

Usually, the water supply line is flexible copper or braided stainless steel. In either case, remove the nut securing it to the 90-degree fitting on the dishwasher (Photo 2). As long as the nut and ring are in good condition (no nicks or gouges; Photo 11), leave them on the line for later reuse. You can bend the copper line slightly, but take care not to kink the line. If you do, you’ll have to replace it. Flexible stainless steel lines are a good replacement. They cost $12 at a hardware store or home center. Make sure you buy them long enough and with fittings that match the old.

Remove the 90-degree fitting for use on the new dishwasher. It’s important to orient it exactly the same direction on the new machine so that the water line feeds directly into it. Otherwise you might kink the line.

Sponge out any standing water inside the dishwasher before removing the drain line under the sink. It’s the flexible hose that’s clamped to an inlet arm on the sink drain or a garbage disposer (Photo 3). As you slide the old dishwasher out, you’ll have to simultaneously work the drain hose back through the hole in the sink cabinet. Keep a rag handy to wipe up the water that’ll run out of the line.

Lowering the dishwasher gives you more clearance to slide the dishwasher out. Chances are the leveling feet will be difficult to turn, but a shot of penetrating oil on the threads may make it easier. If you need more clearance, cut the feet off with a hacksaw blade and turn the screw out. Then be sure to slip cardboard or a rug under them to avoid gouging your floor when you pull out the dishwasher.

Prep the New Dishwasher
Uncrate the new dishwasher according to the instructions on the box. Once it’s uncrated, you’ll find the manuals and installation instructions inside the dishwasher. Review them before proceeding; they may differ slightly from the details we show.

Tip the dishwasher on its back and attach the 90-degree fitting (Photo 5). Don’t reuse your old drain hose; the dishwasher will come with a new one. To prevent dishwasher odors from entering the sink drain, be sure to loop the flexible drain line all the way up to the bottom of the countertop (Photo 6). Some plumbing codes require a special air gap fitting ($7) in the drain line. Call your local plumbing inspector to find out the rules.

The manual will tell you how to adjust the leveling feet and/or wheels to fit the height of the opening. It’s easiest to set these before sliding in the dishwasher. Make minor adjustments after the dishwasher is in. But if your kitchen floor is built up (higher than the area where the dishwasher sits), you’ll have to adjust the feet after you slide it into the opening. If your dishwasher is equipped with rear wheels without adjusters in the back, you may have to set shims (Photo 7) to raise the back to the height of the finished floor. Tack them to the floor so they don’t shake loose when the dishwasher runs.

Slide the Dishwasher In and Reconnect It
Slide the new dishwasher in (Photo 8), grasping it by the sides to avoid denting the front panel. Set the dishwasher in position according to Photos 9 and 10. But don’t secure it to the countertop yet. Wait until you make all connections and adjustments.

Connecting the copper water line so it doesn’t leak can be tricky. The secret is to align it so it slides straight into the threaded part of the elbow (Photo 11). If it’s cocked to one side, the compression nut won’t thread on right and it’ll leak. If necessary, turn the elbow on the dishwasher slightly with a wrench to align it, or gently bend copper lines about 8 to 12 in. from the end.

With the supply line, the electrical cable and drain connected, turn the power and water back on and check for leaks. Recheck the positioning, then screw the dishwasher to the countertop (some screw to the cabinet sides). If your countertop is a synthetic material or stone, and the old holes don’t line up, follow the directions listed in the manual.

CAUTION
If you have aluminum wiring, call in a licensed electrician who’s certified to work with it. This wiring is dull gray, not the dull orange that’s characteristic of copper.

1. Turn off the power, remove the front panel and use a voltage tester to make sure the power is off. Disconnect the wires and pull the cable from the box.

2. Remove the compression fitting nut from the water supply line (water turned off). Note which way the 90-degree elbow points, then unscrew it.

3. Slide the dishwasher drain tube and off the inlet arm on the sink drain. Drain it into a bucket. Remove the screws securing the dishwasher to the countertop.

4. Lower the dishwasher and slip cardboard under the feet. Then gently lift and slide the dishwasher out. Work the drain tube out through the side of the cabinet.

5. Wrap the 90-degree fitting twice with Teflon tape and screw it into the new water valve. Tighten it, aiming the elbow as on the old machine.

6. Thread the new drain line into the sink base cabinet. Loop it higher than the inlet arm on the sink drain or garbage disposer. Slip it on and tighten the clamp.

7. Lay the water supply, drain and electrical lines flat on the floor. Measure the height of the opening, then adjust the wheels and feet according to the manual.

8. Grasp the sides of the dishwasher, lift slightly and roll the dishwasher into the opening. Protect the kitchen floor with a tarp or cardboard.

9. Slide the dishwasher back until it’s flush to the cabinets. Positioning may vary slightly according to dishwasher styles and the style of your cabinets.

10. Adjust the leveling feet with a wrench until the dishwasher is level (side to side) and plumb (up and down).

11. Align the water supply line so it slides straight into the 90-degree fitting. Thread on the compression nut (no Teflon tape needed) and tighten with a wrench.

12. Clamp the drain hose to the dishwasher. Then clamp the electrical wires and connect them. Finally, screw the dishwasher to the countertop bottom.