A few weeks ago we started having knocking in our upstairs bathroom faucet after the hot water has been running full throttle for about 5 seconds. There is a loud bang and the water stops running completely (without us turning the faucet off). We notcied today that when we have the hot water on in other parts of the house there will be a bang after we turn off the hot water.

Any thoughts on what could be causing this? When I first heard the sounds tonight I wondered if it was water hammer but wasn't sure that that would explain what is going on in our upstairs bath as it happens while the water is running (though the water does stop flowing at the same time as the bang). Would water hammer cause the hot water to stop flowing in the upstairs bath?

Thanks for your help/thoughts!

It doesn't sound like water hammer. What type of water heater do you have, My bet's on gas and if it is I have a solution for you. Let me know, Tom