I have a Bosch intelligent all refrigerator 39 upright fridge which has worked faultlessly for three years. Just recently we have noticed water collecting on the plastic bottom skirting of the inside of the fridge, which then leaks out on to the floor when the door is opened. I have also noticed frosting on the inside back of the fridge. Is this a sign of low refrigerant ? Or do you know perhaps what the problem could be. Thanks for your time. Regards Sheralee