When plastic items or dishes placed in the bottom rack of a dishwasher tend to burn or melt while the top rack washes them clean, it is likely due to the proximity of the heating element in the dishwasher. Here's why this might be happening:
Heating Element Location: Dishwashers typically have a heating element at the bottom of the appliance, usually concealed beneath the dishwasher tub. During the wash and drying cycles, the heating element is responsible for raising the temperature of the water and aiding in the drying process.
Heat Transfer: Plastic items, such as containers, utensils, or plates, placed in the bottom rack are closer to the heating element compared to the top rack. As a result, they are more exposed to direct heat and can come in contact with the hot surface of the heating element.
Heat Sensitivity: Certain types of plastics, especially those that are not heat-resistant or labeled as dishwasher-safe, can melt or deform when subjected to high temperatures. The intense heat from the heating element can cause the plastic items to burn, warp, or release harmful chemicals.
Water Spray and Distance: The top rack in a dishwasher is generally positioned higher, allowing for more distance between the items and the heating element. The water spray from the rotating spray arm on the top rack helps to cool and rinse the dishes more effectively, preventing the plastic items from burning or melting.
To prevent plastic items from burning or melting in the dishwasher:
Use the Top Rack: Whenever possible, place plastic items on the top rack of the dishwasher, where they will be further away from the heating element.
Check Dishwasher-Safe Labels: Ensure that the plastic items you are washing are labeled as dishwasher-safe. These items are designed to withstand the high temperatures and water pressure in the dishwasher.
Hand Wash Heat-Sensitive Items: If you have plastic items that are not dishwasher-safe or particularly heat-sensitive, it's best to hand wash them to avoid any damage.
Adjust Dishwasher Settings: Some dishwashers offer temperature control options or specialized cycles for delicate items. Check if your dishwasher has adjustable settings and use lower temperature settings when washing plastic items.
By following these tips, you can minimize the risk of plastic items burning or melting in the dishwasher and ensure that your dishes come out clean and undamaged.