Hot Water Heater Replacement Leak

In removing a gas hot water heater the cold water was shut off at the heater and flex pipe disconnected. The hot side flex pipe was disconnected and residual water was draining from the house pipes. However this draining would not stop and it was at was at a fairly heavy rate. With all house faucets off and cold supply water on to the house, this discharge from the hot water pipe continued. There are 3 single valve faucets in the house. One at the kitchen sink, and one at each of two showers. If this could be the cause, how do I determine which one it is since there are no individual shut off valves for the two showers. Thank you.

One of the shutoffs somewhere is not working and allowing air into the system removing the vacume that would hold the water in the pipes. Df it never stopped ther is a cross connection most likely at a valve/faucet allowing cold water to flow through the hot water side.

valve

Whether the valves could be the problem or not depends on the make and model of the valves. Not all single handle valves can permit the flow to cross over. One way to sometimes locate the bad one is to turn the valves to the "full" hot side and then start draining the water heater. Sometimes you will be able to hear the "roaring" water sound as it passes through the valve. Otherwise just turn off the water to the house.

And if you don't this to happen to you again, then put another gate or ball valve on the outlet of the WH. As they say in New York, It couldn't hoit...

To drain the hot pipes, you need to open a hot tap inside the house to break the vacuum. HOWEVER, if you put a single hande faucet on at any WARM setting, you will of course have cold crossover.