Dishwasher Installation 101

Whether you’re replacing an old dishwasher or installing one where there wasn’t one before, you can accomplish installation by yourself without a lot of hassle. So, how long does it take to install a dishwasher? Depending on whether you are replacing or installing “from scratch,” you can get your new dishwasher up and running in as little as one to four hours.

If you have an existing dishwasher that you are replacing, it’s a pretty straightforward process to simply disconnect the existing connections and reconnect the new one in the same manner using the new attachments provided with your appliance, but how do you install a dishwasher where there was none?

Before you begin, you’ll want to address three aspects of installation. You’ll need a power source, a hot water source and a drainage avenue. It is highly recommended that you place your dishwasher next to your sink for ease of installation and use. Then, you’ll just need to follow the steps.

Install Your Power Source

You’ll need to install a dedicated 15-20 amp circuit from your breaker box if one is not already present. If you require one be installed, you’ll want to drill a hole through the floor into the basement or crawlspace and run a 12 AWG cable from the dishwasher space to the breaker box. Leave ample cable sticking up through the floor in the dishwasher area – about six feet will be sufficient. You will need this extra length while you have the dishwasher pulled out of the cabinet during installation or later service. You’ll need a licensed electrician to install the required circuit breaker and finish your wiring connections. Be sure the breaker remains in the off position during installation.

Drill Holes in Cabinet Wall

You’ll need to connect a drain hose and a water line to the dishwasher. For this, you will need holes between your dishwasher cabinet and your sink cabinet. Your drain hose will require a 1 1/2 inch hole. Use a drill with spade bit or a hole saw to place this hole toward the back of the cabinet. The hole will need to be as high as possible on the cabinet wall while remaining below the rim of the sink basin and high enough that it is above the dishwasher tub. A drain hose installed lower than this will pull water from the dishwasher while it is in operation, resulting in soapy dishes at the end of each cycle.

You’ll also need a ¾ inch hole located near the sink’s hot water supply line for it to be connected to the dishwasher’s water supply line.

Dishwasher Drain Installation

Replace the vertical pipe directly below your sink (drain tailpiece) with a Y, or wye, fitting (dishwasher tailpiece). If your sink has a garbage disposal, there may be a pre-installed fitting intended for a dishwasher (nipple). To use this connection, push out the plastic center of the nipple by tapping it in toward the grinder area of the disposal with a screwdriver or punch and a hammer. Fish out the plug that falls into the disposal through the sink drain with the power securely off. Then secure the drain hose to either the drain fitting or the disposal nipple with a hose clamp.

Connect a Water Source

You’ll next connect your dishwasher’s water line to the hot water supply line under the sink. The simplest method of doing this is to replace your sink’s existing shutoff valve with a dual-outlet shutoff valve so that you can use the same shutoff for the sink and the dishwasher.

Attach the 3/8 inch flexible copper tubing supplied with your dishwasher to the appliance per the directions provided by the manufacturer. Connect the other end to the shutoff valve beneath the sink. Use thread seal tape to help secure all connections and prevent any leaks.

Attach Power Source to Dishwasher

Unless your dishwasher came equipped with a plug-in style cord, you’ll need to hard wire your power source. You likely received a six foot six inch power cable with your dishwasher for this purpose. Remove the base cover on the front of your dishwasher and look for the junction box on the right side to access the wiring. Once you have opened it with a screwdriver or nutdriver, you’ll see a metal junction box to the right side. Remove the bolt on the junction box and locate the ½ inch hole where you will need to install the circuit cable. Feed six inches of cable through the clamp and tighten the clamp onto the cable. Then insert the cable into the hole and attach the locknut to secure the clamp. Strip the cable wires and connect the black circuit wire to the black lead in the junction box using a wire nut. Connect the two white wires with a wire nut. Connect the bare copper circuit wire to the ground screw on the box.

Move the Dishwasher into Place

Ease the dishwasher into the cabinet or counterspace where it will reside. Be careful not to damage any of the attachments while moving it into place. Your appliance should be centered in the opening and the door should be protruding about an inch from the opening. Using a level, adjust the front feet of the dishwasher until it is flush, and the two brackets are in contact with the underside of the countertop above it. A common question asked is, “Do countertops need to be installed before installation?” The answer is no. If no countertop is yet installed, save this step for when it is in place. Place one wood screw through each bracket and attach securely to the countertop. The brackets should not be visible beyond the edge of the counter and the screws should be short enough that they don’t push through the top of the counter.

Check For Proper Function

With your dishwasher installed and set into place, you’ll want to check that it operates properly. Turn on the water in your sink and check for leaks where you made connections there. Turn on the circuit breaker to the dishwasher and start a dishwasher cycle, letting it fill with water and start washing before cancelling so that it drains. Check again for any leaks under the sink or coming from beneath the dishwasher. Put the base plate at the front of the dishwasher back into place.

If there are no leaks and your dishwasher seems to be operating properly, you’ve successfully completed your installation.

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