I have an older model sub zero fridge which was given to me. I can't find the model number, but it has the grill on top, and the freezer on the bottom. It has two temperature controls, one for the fridge and one for the freezer. They're number dials, not temperature dials, and I don't know what to set them at. Also, there's a little water on the floor in the rear. Is that normal? Thanks.