Dishwashers vary somewhat from one model to another, but they all work essentially the same way. The dishes are held in sliding, removable racks. Water sprays from underneath by means of a spray-arm to remove food and debris from the dishes. (Some dishwashers have upper and lower spray arms.)
Food that falls away from the dishes collects in a trap in the bottom of the dishwasher interior. The trap is removable, and should be taken out and cleaned periodically to remove dried soap and food particles. Making sure the trap stays clean will help ensure that the dishes come out clean.
The sprayer arms work by spinning to help ensure that sprayed water reaches all of the dish surfaces in both the top and bottom racks of the dishwasher. Water sprays out of the device by means of small holes placed at regular intervals along the arms. Eventually these holes can become clogged with debris particles or dried soap. To help ensure that your dishes get their cleanest, clean out the holes in the spray arms periodically. Soak the arm in a solution of vinegar and water, and use an ordinary pipe-cleaner to clean the holes.
If you have a problem of water leaking onto the floor around the front of your dishwasher, the problem could be a damaged or worn out gasket around the dishwasher door. In most cases, the gasket can be easily removed. Take it to your home center to ensure that you get the proper replacement.
If you’ve noticed rust on your dishes or in your dishwasher, it could be that the coating has come off of some of the prongs in the racks. Inexpensive dishwasher repair kits are available, and include vinyl paint and rubber tips that can be used to cover rusted spots on the prongs.
SOURCE:http://www.diynetwork.com/how-to/rooms-and-spaces/kitchen/dishwasher-maintenance-basics
