Hot water shut off valve failing

[gGb164OwAY]

The hot water shut off valve under my kitchen sink is failing: when I try to close it, the hot water in the faucet continues to run (cold shut off works as intended). I need to shut of the water in order to fix a small, pinhole sized hole in the copper pipe above the shut off valve. I tried shutting it off both with the faucet running and with the faucet turned off. No difference, turning the shut off valve does nothing.

I am thinking about replacing the failed hot water shut off valve. Trouble is I am not sure how to prevent the hot water from flowing from the pipe in the wall since there is no shut off going out of the water heater. Any advice?

[worms]

Might depend on your water heater, but if there is no outlet valve, look for an inlet valve, turn it off and drain the water heater tank. (Make sure you turn the heater off properly first!)  Failing that turn the mains supply to the house off and then drain the hot tank.  While it is drained, install an inlet and outlet valve as well as the one at the sink.  You can never have too many valves in the system! :)

But before all that, can you see if the shaft of the valve is actually turning when you turn the handle? Best to rule out a slipping handle before you dismantle the rest of the system!

[music lover]

You will have to shut off the water at the source...in most houses there is a shut off at the meter.

Tip: When replacing the shut off, get a ball shut off valve instead of replacing it with another cheap one. They are virtually foolproof, and IMO, should be the standard.

[Spork]

You will have to shut off the water at the source...in most houses there is a shut off at the meter.

Tip: When replacing the shut off, get a ball shut off valve instead of replacing it with another cheap one. They are virtually foolproof, and IMO, should be the standard.

+1.

There is also the possibility that you can repair your existing valve.  The old style shut offs are extremely prone to failure, but you can often replace the rubber seat washer. 

Replacement is a permanent fix.  Repair is quick and easy and costs about 25 cents.

[PFHC]

The above folks have it right. Just shut off the water to your house, find a handy drain point and bleed off the pressure.

Cheapest:
The valve maybe be able to be dismantled. If so, inspect the seats and see if there is anything you can do to improve the seal. You mabe able to build up the seat with your magic fixer of choice... JB Weld, 5200, plumbers epoxy, etc.

Less cheap:
If not, get a shark bite coupling (which will adapt copper to PEX), and replace the damaged section of copper with PEX. Much cheaper and a trillion times easier to work with. Do this with most any of your copper that is damaged. And yes, add as many valves as you can to make a job like this easier in the future.

[gGb164OwAY]

Thanks a lot, all. Great advice. I followed the advice -- turned off cold water inlet at the meter, opened faucets to bleed off cold and hot water pressure without having to empty or turn off the water heater, proceeded to fix the shut off valve for hot water by replacing it -- and it's working well.

[FIRE me]

You should feel terrible. Somewhere, a plumber is starving.

Just kidding zabidlo, you're a total bad ass.    :-)    Basic plumbing skills will save you crap tons of money.