During cleaning, the"ZiZi" noise is norm. Everytime when you turn on the machine, the working time should not too long, please pause 5 minutes to radiating after it worked about 15 minutes, in order to better protect the machine, and reduce the failure rate. Note: The machine's heating function is just a auxiliary function, you can begin to clean your things when the temperature at 20? You need not to added a higher temperature before cleaning.