почему аппарат не стартует

Good afternoon. The problem is this: there is anova precision cooker. After the appliance is immersed in water, I press the play button. The apparatus starts to make a long squeak and does not start circulation. There is a problem with the water level sensor, the device does not understand that it is immersed in water. What do i do? There are already 5 such devices and the problem is the same.