Shutting off just the hot water to the house

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Old 02-11-20, 08:19 PM
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Shutting off just the hot water to the house

I can turn off just the hot water by shutting off a valve immediately downstream of the water heater, correct?

The valve on the left side of the pic (with the red 'base' as the pipe exits the tank) - close that off and no water in the hot water pipes, correct?


Do I need to do anything to the water heater prior to closing that valve? Replacing the dishwasher and figured why turn off all the water if turning off just the hot water will suffice.

 
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Old 02-11-20, 08:36 PM
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Have you looked under the sink to make sure there's not already a valve there?
There should be a two valve installed under the sink.
To answer your question, yes shutting the valve off on the left with the red ring will shut the water off, there is no need to do anything to the water heater.
Even with the valve off there will still be a small amount of pressure on the line, just open the hot side of the kitchen faucet.
PS, there never should have been a shut off valve on the output side of the heater, only the cold side.
 
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Old 02-11-20, 09:48 PM
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The handle on the left shuts off the water leaving the tank. As Joe mentioned..... there shouldn't be a valve there. What I usually do when I see that is to take the handle off and using a cable tie.... tie it to the pipe.
 
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Old 02-11-20, 11:18 PM
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Why shouldn't there be a valve on the output side of the water heater? There's another valve several feet downstream (toward the fixtures); looks like where the installer had to join a couple of pipe sections with bends, he decided to throw a valve in between.
 
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Old 02-12-20, 05:53 AM
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To answer your question, yes shutting the valve off on the left with the red ring will shut the water off, there is no need to do anything to the water heater.
Even with the valve off there will still be a small amount of pressure on the line, just open the hot side of the kitchen faucet.
Joe, It's not that your answer is wrong, but it's bit misleading. That valve as stated by you and others should not be there AND should never be turned off! That close to the heater and pressure can build to a possible dangerous level. Your answer made it sound like "close it and forget it". We don't know why the poster wants to close it. Short term repair or long term remodel or repair. The real correct answer is to turn off the water heater and turn off the cold water supply.
I also installed that valve on my heater (with a sign to never close it, I like PJ's idea if removing the handle), for the sole purpose of making repair or replacement easier by not having to drain the hot water pipes. Just an observation.
BTW...as far as I know this is not to code and if sighted by an inspector he can make you remove it.
 
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Old 02-12-20, 06:00 AM
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When you are going to work on the plumbing, after turning off the water you need to drain the plumbing above where you are working to prevent a slow drip (or even a short torrent) out of the open pipe where you are working. Here, only the hot plumbing needs to be so drained.

Start by turning off just the valve above the cold side of the water heater. Then open a variety of hot faucets upstairs to let out most of the water in the pipes above. Finally, drain about a gallon of water (no more) from the water heater.

Turn off the water heater heat before draining any significant amount of water from its tank. Do not turn the heater back on until the plumbing is assembled and you have a torrent of water out of a hot faucet for a full minute.

Do I see an expansion tank on the right that is attached to the cold water line?

An expansion tank in the cold water line should be positioned so there is no valve or check valve or other gizmo between it and the water heater.

It is almost never necessary and is often problematical to have shutoff valves on both ports of the water heater. There is one obscure exception. If you have two (or more) water heaters in parallel (or in series with bypasses) for more hot water or for fuel choice, then if one springs a leak nothing can operate until that heater is replaced unless you can isolate it with shutoff valves on both ports.
 
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Old 02-12-20, 06:53 AM
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Have you looked under the sink to make sure there's not already a valve there?
OMG, just turn off the water at the dishwasher and be done with it!
 
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Old 02-12-20, 07:29 AM
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OMG, just turn off the water at the dishwasher and be done with it!
Ah..the simple solution so often eludes us.
 
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Old 02-12-20, 09:11 AM
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Of course the very first place I looked was under the sink. Whoever last messed with this valve (probably many years ago when the existing dishwasher was first installed), left the valve without the handle.

The copper line in the lower left is running to the dishwasher.


Very little working room here.


I tried tightening that little square nub with a wrench, but after several 1/4 turns, it feels like that nub is starting to deform (and line is still partially open). Hence this thread about shutting off hot water farther upstream. Figured I'd shut off the hot water, empty line, replace the dishwasher, and try to wrench that shutoff valve by the sink back to it's original wide open position - and pray it doesn't start to leak - getting in there to replace that valve would be tough given the lack of working room.
 
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Old 02-12-20, 09:35 AM
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Replace that valve! Might be tough but it needs to be done. You can use a Sharkbite to make the job easier. I would cut out the copper tubing, add an elbow and use rigid copper pipe.
 
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Old 02-12-20, 12:30 PM
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That square hub as you call it is threaded to accept a screw. If you have a screw that fits screw it in to stop the brass from defoming. You could go to a store and if you can't get another handle, even if you had to buy another valve and just use the handle it may save you a lot of work. Valves are cheap and might be worth a try.

Just a thought.
 
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Old 02-13-20, 03:56 PM
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The handle idea is a good one; I picked up a handle, but the square nub is a bit too deformed to press the handle on. Really not enough working room to get in there and file it back to perfectly square. I should have gotten a handle before putting a wrench on it!

So shutting off that valve is not an option at the moment, and I don't want to get into the bigger project of replacing that valve (that's a someday/maybe project).

OK, so I gather the issue with turning off the valve on the outlet side of the water heater is too much pressure buildup. There's another valve ~6ft downstream - would that be better? Duration of shutoff would be long enough to drain the water out of the line, remove the dishwasher inlet hose, clean up whatever gook is on there, wrap dishwasher inlet male end with white thread seal tape, and screw on the inlet hose.

Or is it necessary to turn off the water heater and go through steps outlined by AllanJ?
 
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Old 02-13-20, 06:59 PM
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What does the piping look like behind the dishwasher? You might be able to simply add another valve on the supply line in that location (you can use a compression fitting or shark bite valve on the copper line if you are not comfortable soldering). This would allow you to leave he mangled valve in place, in the open position, never to be needed or used again.

 
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Old 02-13-20, 08:26 PM
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@Rockledge, that rigid pipe connects to a braided steel hose via an adapter. Braided hose connects to dishwasher inlet.

Yeah, I could add a 1/4 turn ball valve, and there's a lot more working room in the area the dishwasher sits. Or, when I shut the water off, I could just connect the dishwasher and not worry about the old valve or adding a new valve for a long time. But certainly, if I want (or need) a shutoff at the dishwasher, doing as you suggest would be a lot easier than messing around with that old valve.
 
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Old 02-14-20, 09:07 AM
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First - just replace the guts of the valve- the valve unscrews and can be replaced. circled in blue.

Second- if you're going to do soldering, bring along an old cast iron frying pan to avoid setting the cabinetry on fire. circled in red
 
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Old 02-14-20, 09:18 AM
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@Hal_S, if replacing the guts of the valve is possible without cutting and making new connections (via solder or pex or other), that would be sweet. The nut you're suggesting to loosen is the 4-sided nut that sits behind the hex packing nut?
 
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Old 02-14-20, 09:22 AM
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@Norm201 (or anyone else), to shut off the hot water, can I just turn off the outlet valve (hot water) on the water heater, and to prevent an overpressure situation, shut off the gas supply to the water heater?

Seems like that would be (1) simple (no fussing around with partially draining the tank, etc.), (2) safe (no overpressure), and (3) still allow cold water use for the duration of the work in case I run into any delays.

Edit: Another option - instead of shutting off gas supply, this water heater has a vacation setting, which sets controller to 55*F. Same idea - no overpressure.
 

Last edited by cartman; 02-14-20 at 09:40 AM.
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Old 02-14-20, 10:34 AM
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Sure go for it.___________

 
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Old 02-14-20, 02:14 PM
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I think the simplest answer for you to understand is if the tank is not making HOT WATER there is no excessive pressure being produced.If you want to close that hot water valve on the tank just make sure the tank doesn't run for hot water.

There is no reason to drain the tank. If you have a standing pilot model you can turn the gas valve to pilot so it will not run. If you have an electronic ignition you can simply turn off the gas.

As far as removing the guts to that shutoff, yes you can if you can get the nut loose below the packing nut on top. It will just unscrew and you can replace it with a new one but it must be the same brand valve or something that fits. There are different brands. To do this though you must first, obviously shut the water off and if you could shut the water off you wouldn't have to go through this.

Just a thought. If that silver valve is the shutoff for the dishwasher why can't you just shut that valve off to isolate the dishwasher. That would kill the water to the unit unless I'm missing something.
 
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Old 02-14-20, 03:16 PM
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I would replace the valve using a sharkbite or a compression valve.
Does not look like you will be able to use a pipe cutter so go slow cutting it as you do not want to deform the pipe.
Also it is important that the pipe be cut at 90 degrees.
Be sure to clean up any burrs etc. and clean the outide of the pipe with fine emery cloth.

Below the valve is a problem because of the bend. The pipe is probably out of round already.
Looking at the glob of stuff on the bottom of the valve I would say that there has already been a leak problem.
I do not know how long of pipe you need from the valve to the dishwasher but if possible I would get a braided hose. They make fairly long ones for dishwasher installations often the kit includes an adapter for the dishwasher valve.

Shut off the hot water.
Shut off or turn down the tank.
Open a hot water tap upstairs.
Open a hot water tap downstairs.
There will still be some water in the line to dishwasher so have pans handy.
 
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Old 02-14-20, 09:35 PM
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So I set set the water heater's dial to Vacation mode (55*F), shut off the outlet valve and drained the line. Very simple; easier than messing around with draining some of the water out of the tank. Given the discussion about overpressure, I'll label that valve so that no one else shuts it off.

As for the missing valve handle, I skipped it this time. Someday/maybe I'll tackle this - and I'll definitely try removing the guts of the valve first. That'd be a lot easier than cutting and reconnecting pipe with very little working room (can only get one arm in there because the cupboard opening is very narrow). And if I had to cut the pipe, I'd use a different connection than solder. As was pointed out by way of the old burn marks, using a torch in there probably not the best idea.

@spott, that silver valve is the shutoff for the hot water to the sink faucet (you can see the braided steel hose running off that valve and to the right, which is where the kitchen sink is).

Thanks to everyone for the info and advice. Got the job done and I'm a little more educated about the water heater and manipulating hot water in the house.
 
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Old 02-15-20, 08:01 PM
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Thanks for the update............
 
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Old 02-20-20, 08:01 AM
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wrong thread, nevermind ...........
 
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