Installing a built-in dishwasher requires basic mechanical, electrical, and plumbing skills, so the average handy person can install a dishwasher in 1 to 3 hours depending on if it is a new installation or a replacement dishwasher. If you are replacing an existing dishwasher, it will take less time.
1. Prepare the cabinet area in which the dishwasher will be installed. The opening should be 24 inches wide for most models, 24 inches deep and 34 1/2″ from the floor to the underside of the countertop. The back wall can not have pipes or wires on it. The power and water supply lines will come into the cabinet in the 4″X4″ area at the bottom back of the cabinet through a 1 1/2″ hole. Make sure the floor is level and the cabinet is squared.
2. Choose your drain method based on your local codes and height of the drain tee. Some codes require an air gap. If the drain tee is less than 18 inches from the floor, you must use an air gap. If an air gap is not required and the tee is over 18 inches from the floor, you can use the loop method for the drain connection. If the drain hose will be connected to a garbage disposal, you have to remove the knock out plug so that the dishwasher will drain.
3. Inspect or install wiring by making sure there is a 120V, 60Hz dedicated circuit with a 15 or 20-amp breaker or time delay fuse. Wiring has to be 2 wire with a ground and rated for 75 degrees Celcius or 176 degrees Farenheit. The wiring can come into the cabinet from either side in the rear bottom area. The hole should be a maximum of 1 1/2″, and it can be the same hole used the the water supply line and drain hose if its being hardwired. If it is a flexible power cord, it must have a separate hole. Hardwiring cable will come up the right side along the bottom 24 inches of the cabinet to the right front electrical connection on the dishwasher.
4. Prepare the water supply line that enters through the 1 1/2″ hole in the rear bottom of the cabinet. Turn off the water to install a hand shut-off valve under the sink. The water connection is on the left side of the dishwasher. Use 3/8″ O.D. copper line to extend a minimum of 19 inches from the rear wall. The water heater should be set between 120 and 150 degrees (closer to 120 if children are in the home to prevent scalding accidents) and the pressure should be between 20-120 PSI.
5. Prepare the dishwasher by checking the door balance and adjusting the spring tension if necessary. If the legs have to be attached, do that close to where it will be installed.
6. Connect the drain hose to the dishwasher’s drain port if it did not come factory-installed. Position the electrical wiring and water supply lines so that the base of the dishwasher will not catch them. Slide the dishwasher in front of the opening so that you can feed the drain hose through the hole you drilled for it.