Dishwashers are connected to the hot water line, which allows the dishwasher to wash with the hottest possible water. Hot water commonly is more effective for cleaning the dishes and, coupled with the heat cycle of the dishwasher, can sanitize the dishes. Dishwashers do not have a cold or warm cycle like a washing machine.
If the plumber installing the home water system contemplated a dishwasher, the hot water line under the kitchen sink will have two valves. One controls the water service for the sink; the other is meant as a connection for the dishwasher. Contact a plumber for installation if a second valve is not present.
Flexible copper tubing is commonly used to connect the hot water valve to the dishwasher. This tubing is sold and delivered in rolls or coils that must be carefully unrolled. Ferrules and compression fittings are used at both ends of the copper tubing. Properly installed, the tubing connects the hot water valve to the input valve of the dishwasher without leaks.
The drain and water pipes under the sink can also serve the dishwasher, which makes the most economical position for a dishwasher to be located next to the kitchen sink. Other placements are possible if the plumbing is provided in those locations. In those cases, only a drain and hot water line would need to be installed.
Keeping It Hot
Running the hot water in the sink until the water is hot brings hotter water to the dishwasher. While the water system sits idle, the water in the hot water pipes cools, which reduces the temperature of the water used by the dishwasher. Running the water until it's hot operates the dishwasher with hotter water and may improve cleaning results.