I want to add a blanket to my electric water heater. It seams simple, roll the blanket around the heater and tape the ends. There is a pipe that comes out the top and over the side of the heater. It has some sort of valve on it. It hangs over the side of the water heater right up against it. Maybe it is some sort of pressure valve? Anyway, does the blanket go over top this pipe or must I compress it under the pipe.