Plumbing help Update: It's fixed!

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I have to repair a leaking shower faucet. My question is this: I have to turn off the water supply to do it. However I have a gas hot water heater. If I turn off the supply, wouldn't the tank drain, since it's leaking hot water? Would the water heater keep trying to heat non existent water? And would that cause a problem? I have no idea. Plumbing is something I never had to do, until now. Do I need to shut off the water heater while I do the repair? Or are there safety features in place to keep things from going critical? Again, I'm far at sea on this one. Any help is appreciated.
 
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Typically, all you need to do is shut off the main water supply valve, wherever it is located (usually at or near the meter). Don't worry about the water heater. Most shower mixing valves contain a cartridge which can be fairly easily removed and replaced. There is a simple tool made which will aid in the cartridge removal. Home Depot, Lowe's, etc. has them. Should be about a 5 minute job. But I don't know what kind of mixing valve you have.

Look on YouTube if you are confused. [ame]https://www.youtube.com/watch?v=MkPcCmYkG4Q[/ame]
(there are other videos)
 
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You're thinking correctly, I would shut off the hot water heater if you'e going to leave the water turned off for a while. Check on yours for the gas or electric shutoff. A photo of your hot water heater would be helpful for a more detailed answer.
 
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I would think that turning off the main water line (so there's no pressure) wouldn't cause the tank to drain as there is no "draw"on the HW line. Plus the HW outlet from the tank is at the top, so whatever HW is in the line from the shower faucet leading back to the tank will just sit there.

But "I'm not a plumber and I don't play one on the internet", at least until now :)

EDIT: I just saw "mercury's" post above. Good point to shut off the heater anyway.
 
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You don't need to turn off the water heater to repair/replace the shower valve but if you want to keep it from coming on while working on the valve just turn the water heater control to "Pilot". Then when finished turn it back to where you normally have it set.

Oops, a little late.
 
You don't need to turn off the water heater to repair/replace the shower valve but if you want to keep it from coming on while working on the valve just turn the water heater control to "Pilot". Then when finished turn it back to where you normally have it set.

Oops, a little late.

Greg, better late than never. Or some such thing.:D:D
 
I will not normally turn off the gas to my water heater. If you feel it is necessary, some gas regulators will have a "vacation" setting on the temperature control dial that allows the pilot light to remain on but the main gas burner will be deactivated. I imagine turning the dial to "pilot" does the same thing. In any event, turning the main water valve off is all that is necessary for 99% of home plumbing jobs. During my life I have replaced at least a half dozen shower valve cartridges. They don't go bad very often.
I have noticed that just the pilot light alone will keep the water in the tank comfortably warm indefinitely, at least warm enough to take a shower.
If anyone needs a lesson on the easy way to acidify the scale inside a gas water heater tank, I can provide that also. I have done that several times.
 
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Pay the pros. It's cheaper to pay the pro for the repair than pay the pro for the repair plus the damages you caused trying to do the repair.
 
As a plumber will generally hit you for about $200/hour today, I will do my own plumbing work whenever possible. Most plumbing problems are not that difficult to fix by someone with average abilities and tools. And then there is YouTube to help.
 
YouTube has gotten me through lots of jobs I had no previous experience doing, mainly concerning working on cars. Two of the most valuable internet websites are YouTube and Wikipedia. I have noticed that the articles in Wikipedia have become far more comprehensive and scholarly than they formerly were. Wikipedia is usually my first stop to get information about something I need to know in a hurry. Just used it tonight to get information about vinegaroons I needed to find out. It was all right there.
 
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YouTube is okay if you know enough to weed out the idiots. It's like asking ten people for computer help; you'll get fifteen different answers.
 
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