I have cold water leaking into the hot water side of my hot water tank. In order to get hot water shower, I have to flush a toilet or turn cold water on at a different location.
With the cold water inlet side of tank closed, you can hear water coming in on the hot water side.
Best Answer
If water is flowing back through the hot line with the shut off valve closed on the cold (inlet)line would indicate a leak in the tank or a faulty shut-off valve not completely closing. If the supply valve is off (closed) water flow stops. Check for air in the tank by opening the pressure+ relief valve with the cold valve shut. Water should sputter from it (hot! be careful) or air, initially and than water. Also, if possible, check for a H+C pipe reversal along the out going tank line. Primary locations to check would be the fixtures you are opening to increase the hot water temperature.