It's 4 degrees here and supposed to get down to -9 tonight. I have lots of cold water but no hot water. Can hot water pipes freeze? If so, why haven't the cold water pipes frozen? I have opened all of the cupboard doors, turned the heat in the house up and opened up all of the hot water faucets in the house. One faucet has water coming out of it, but it isn't even a little warm. How do I get the hot water to start flowing again? Thanks!