I have an electric hot water tank that is in good working order (it has been checked out professionally) The problem is that when any of the hot water taps are turned on in the house, we get instant hot water but after about 20 seconds turns to lukewarm. It feels like cold water is mixing in with the hot water.
The house is about 24 years old and I remember something about a hot water loop or parallel gravity pipe being installed by the plumber so that you would not have to wait for hot water. Could this be the problem and how can it be remedied?