Just got a strange issue where the kitchen sink will deliver only a trickle out of hot water tap when opened, the cold water flows just fine, the hot water works at every other point bathrm sink,tub,laundry. I'm looking at replacing the facet in the kitchen and realized the (hot water) shut off valve at my kitchen sink wont stop the flow turning it doesnt affect it at all. And it doens't appear i have any other place to stop the flow before the water tank, so i guess my question is do i have to shut off and drain my hot water tank in order to replace facet and shut off valve? Thanks in advance.
Replacing a leaking stop valve requires shutting off the water upstream. If your water heater is the next practical upstream shutoff location then it is fine to shut it off there.
If there is a shut off valve available on the water heater outlet then you do not have to shut off the water heater if you complete the repair in a reasonably short amount of time (a day). Is this case you would not drain it. You should close the inlet to the water heater, open a hot water faucet downstream, then close the water heater outlet valve. This will relieve stored pressure in the water heater.
If there is no shut-off on the outlet and you shut it off on the inlet then you still do not have to turn it off as long as the stop valve repair is above the height of the heater, as it will remain full of water.
If there is no shut-off on the outlet and the stop valve repair is below the level of the water heater, the water heater may drain out as you open a faucet to relieve pressure on the line so you can work on it. In this case you should turn the water heater off.
- There is no need to drain the water heater
- if the water heater remains full and the repairs can be completed in a reasonably short time, there is no need to turn the water heater off
- if the water heater is or becomes drained for any reason, it must be turned off immediately