Very sensitive device for such a high cost! I have already replaced the first one as defective, but it seems that they all have a problem. One mixes but doesn't heat, the other doesn't work in the desired setting.. I have tried all possible combinations (with or without ice water, different sockets in the house in case there is a voltage issue), but it works whenever it wants. At least it mixes well, dissolves the milk powder correctly. I definitely do not recommend it, it's a huge cost for it not to work!