On any water heater, the shut off is on the incoming cold pipe.
the hot water valve shut off valve shuts off the hot water. The cold water valve shuts off the cold water. ;()
An air-intake engine shut-off valve regulates air-flow to the motor, and operates as an emergency shut-off valve. There are also shut-off valves on water hoses, so shut-off valves really control the inflow of any liquid or gas.
Outside at the main shut off valve. Showers/Bathtubs do not normally have a shutoff valve like sinks and toilets. The main water valve for the house must be turned off.
If the shut off valve turns but does not shut the water off, the washer in it has split and probably made it to the faucet. It was blocking part of the hole on the hot side and at some point either shifted or made it through the faucet and in in the screen in the end of the spout. Shut the main water off and replace the washer in the shut off valve.
The valve seat or washer on the main valve are not seating/sealing properly.
Flow control valve that will over come stratification of hot water flowing through the system until a circulator comes on
With the water main shut of valve of course
A non-positive shut off valve is one that is controlled by the user. You hold down the valve to keep the water or whatever coming out, and when you want it to stop, you release the valve.
There is no shut off valve. But you can by pass the heater core by disconnecting the 2 hoses going to the heater core. And connecting them together. The only problem with this is that you won't have any heat in the winter.
Shut the water off at the main shut off where it comes into the house or at the meter and change the valve at the fixture. The valve at the fixture may be sweated on, compression, or threaded.
This depends what shut off valve is in question here. Where the leak is and what type of material is the shut off valve made of.
If electric shut off the current to the elements, if gas shut off the gas valve. Open a hot water faucet to give it air, open the drain valve on the bottom of the heater.