Do you have a Bosch or ASKO dishwasher that is not working properly, but you continually hear a whirring noise as though something is running even when the dishwasher is off? Your dishwasher may have a leak.
On ASKO, Bosch, and select other import dishwashers, there is a wafer in the bottom of the dishwasher pan. When water accumulates in this pan and soaks the wafer, it expands and rises until it presses upon a microswitch, called a float switch. If the switch continues to be activated, with the dishwasher off, the dishwasher knows that there may be a leak of some kind. To minimize the risk of the machine leaking onto your beloved kitchen floor, the dishwasher continually runs the drain pump until either the machine dries out or is fixed.
Keep in mind that the drain pump running continually is not the problem, but the symptom. If any tubes and hoses are clogged or dirty, the compartment with the float switch may be unable to drain properly, incorrectly signaling to the dishwasher that there is a leak. If this is the case, the component parts of the dishwasher need to be disassembled, cleaned and dried out. If the problem is a leak, the next step should be locating the source of the water leak and fixing it as soon as possible, before the problem gets worse. For both, you should rely on a professional appliance repair service.