Capping a hot water supply.


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Old 07-19-11, 05:14 AM
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Capping a hot water supply.

Hello all,

I recently removed my dishwasher, and I do not plan on replacing it with another one. So, I need to cap off the hot water supply line that was feeding it. There is a 3-way valve on the hot water pipe that splits to feed both the sink and the dishwasher. Is there a fitting I can use to cap the old DW supply line that won't leak when this valve is left open (because I need to turn the hot water back on for my sink)? I tried a 3/8" compression cap; it fit well but leaked steadily when the valve was opened.

Note: replacing this valve altogether would be a hassle - there is no shutoff to my unit, so to turn the water off I have to schedule with the HOA for a time to shut the water off for the whole building.

 
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Old 07-19-11, 09:02 AM
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Be sure you really have a compression cap not a flare cap. Not supposed to be needed but try Teflon tape. Buy a cap from a plumbing supply or at least a different store. I have seen defective brand new products. Hopefully different store different brand or at least manufacturer's lot. Try to get one not made in China.

You could test if it is the valve by switching the sink supply line to where the dishwasher was and cap to where sink is currently hooked up. If cap still leaks and supply line doesn't when hooked to where the dishwasher was you know it is a bad cap.

Get a plumber in to install a cut off valve for your condo if you own the condo. That way in the future a lot less hassle. (Assumes non-interconnected plumbing between condos.)
 

Last edited by ray2047; 07-19-11 at 09:27 AM.
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Old 07-19-11, 10:32 AM
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I dont think they make a cap for valves. The thread pattern is too fine. Before you mess the threads on that valve, take a step back and rethink it.

What we do is put a cut off short copper supply line. Hammer the end shut flat and solder the flattened end to seal it.

If you cant do that you can get a flex line for a sink and install it. On the side that would go to the sink install a 1/2 close brass nipple and brass cap.



I hope that makes sense.

Mike NJ
 
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Old 07-19-11, 10:53 AM
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Ah, you guys aren't thinking it through. Yes, they DO make caps for compression fittings BUT they need a gasket that doesn't come with the cap. You need to get a piece of rubber and cut out a gasket or two.

What I did a few years back when I had to temporarily close off a line that had a compression union was to remove one side and add the compression cap. It leaked just as esvoytko wrote. I took the cap off and used a 1/2 inch arch-type gasket punch to make a couple of round discs that fit inside the cap. I used two because the sheet rubber (it may have been a synthetic rubber) was fairly thin. I screwed the cap back in place and no leaks. It was that way for about three years before I finished the project.

esvoytko, You might be able to find an O-ring that will fit the cap and work as well as a flat gasket. Be sure it is a fairly thick O-ring with an inner diameter significantly smaller than the outer diameter.
 
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Old 07-19-11, 11:37 AM
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Ok not a pro but I did just check Google. First there is the terminology confusion. What I call a compression nut some sites call a compression cap but I did see some actual compression caps. If the one the OP bought has no gasket I'd think it is manufacturing error.

Actually though I almost gave the same solution with a supply line, nipple and cap as Mr. Lawrosa but I didn't want him laughing at my redneck solution so I deleted it.
 
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Old 07-19-11, 11:45 AM
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Actually though I almost gave the same solution with a supply line, nipple and cap as Lawrosa but I didn't want him laughing at my redneck solution so I deleted it
Its only redneck if you live south of the mason dixon line. Up here in the north we do what we want.....LOL

I only suggested that because the OP cant turn off the water with out shutting the whole units down. I never laugh at anything really. I have seen crazy stuff in my day. It may look hokey but really there is nothing wrong with it.

I saw a kitchen faucet once that had the spray install under the cabinet. There was no hole for the spray at the sink and the plumber did not know enough to cap the port with a 1/4 " brass cap.

Mike NJ
 
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Old 07-19-11, 12:51 PM
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If the one the OP bought has no gasket I'd think it is manufacturing error.
You would think so but I have seen many of the caps in their little plastic bags and none of them had any kind of gasket. For what it's worth, the manufacturer is a big company that makes lots of plumbing parts and has a W for the first letter of its single syllable name.
 
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Old 07-19-11, 01:04 PM
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Originally Posted by Furd View Post
You would think so but I have seen many of the caps in their little plastic bags and none of them had any kind of gasket. For what it's worth, the manufacturer is a big company that makes lots of plumbing parts and has a W for the first letter of its single syllable name.
I wonder if a ferule would work?
 
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Old 07-19-11, 01:08 PM
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Properly sized O-rings are better than a gasket. Ok...not better..just easier. I have t do the same with the drain for my swamp cooler line every year when I put the pressure back to it.
 
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Old 07-19-11, 06:10 PM
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Thanks for the all the replies.

Ray2047: Plumbing is interconnected haphazardly between units. Hell, even the outdoor spigot is run directly from under my sink (that's the white plumbing line seen in the photo). That's why there's no individual shutoff.

lawrosa: Just to clarify, are you suggesting I add a short length of copper pipe and then solder or cap the end of it shut?

Furd: The compression cap I used was indeed a Watts, and it came in a little plastic baggy with NO gasket. Where can I buy the rubber O-ring that you mention? Is it possible to find a cap nut with a rubber gasket already installed, something like this:



Would that be able to handle the pressure indefinitely?
 
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Old 07-19-11, 06:51 PM
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lawrosa: Just to clarify, are you suggesting I add a short length of copper pipe and then solder or cap the end of it shut?
Yes. Get a normal copper sink supply line. Cut and use about 1 1/2" or so. Tap one end closed flat like a flathead screw driver. Sand the end with a wire brush or emery cloth. Flux the end and solder the tip where the copper tube came together when you tapped it flat. Then install it with a nut and ferrule like a normal supply.

You made your own cap. This is a oldtime plumbers trick. They did not have caps I believe and thats what I was taught.

Heck when we were roughing homes and ran out of 1/2 caps thats how we capped all the lines in the home for the water test. When your starting out in plumbing fittings are expensive. This is how we saved money on the jobs when I was a kid just starting out. Then when it was time for the finished work we just cut the end and install the valves....


Mike NJ
 
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Old 07-19-11, 07:28 PM
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There are several ways of dealing with this. Mike's suggestion is a good one but as long as you need to go to the homecenter to get some supplies I would suggest using a "stub out" tube instead of smashing and soldering a piece of tubing. The stub outs are short pieces of copper tubing that have the ends closed. They are normally used to "stub out" from the rough plumbing through a finished wall for testing purposes. After the test and during trim out the plumber cuts off the closed end and attaches shut-off valves.

(image courtesy of Quinby Hardware)

You would slide a compression nut and new ferrule on the open end of the stub out and then attach it to the existing shut off valve.

OR, if you have soldering skills you could just use a short piece of copper and then solder a cap on it. This would be easier (in my opinion) than smashing the end and soldering as Mike suggested. The cap is maybe 75 cents.

If you want to try the gasket or O-ring in the cap you already bought try to get an O-ring that fits snugly inside the cap. If it is too small it might not seal. O-rings of various sizes are usually available at the homecenter but they might be found with the specialty hardware (nuts and bolts) in the little drawers. You might even get away with a bit of silicone sealant in the bottom of the cap. If you try this don't make the silicone too thick and try to make it even. Wait at least 24 hours for the silicone to set up.
 
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Old 07-19-11, 07:35 PM
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Mike, do they make water hammer arrestors with plain ends that might be fitted using a ferrule and compression nut? That might be the best method.
 
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Old 07-19-11, 11:31 PM
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Furd that valve is for a 1/4" supply. I dont think they make those stub outs in 1/4"

Mike NJ
 
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Old 07-19-11, 11:53 PM
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I will try to find an o-ring that fits; that seems like the most straightforward (and elegant) solution. The stub-out idea sounds like a good plan B.

Will post back with my results.
 
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Old 07-19-11, 11:54 PM
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Looking at the picture again it is plain the inlet is 1/2 inch nominal and the straight through outlet is smaller with the lower outlet smaller still. Maybe the straight through is 3/8 and the lower is 1/4. I can't tell from a picture so forget everything I wrote except about the gasket or O-ring in the cap.

Thanks for pointing that out, Mike.
 
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Old 07-20-11, 12:07 AM
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IM sorry I meant 3/8". My head is off tonight. Got other things on my mind. 2am I am going to bed...

Both outlets are 3/8" with 1/2" feed.

Mike NJ
 
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Old 07-20-11, 04:28 AM
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Since the valve is compression, would it not be easier to just change the valve to eliminate one outlet than to reinvent the wheel? Just a naildriver's opinion, mind you
 
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Old 07-20-11, 05:22 AM
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Originally Posted by chandler View Post
Since the valve is compression, would it not be easier to just change the valve to eliminate one outlet than to reinvent the wheel? Just a naildriver's opinion, mind you
But it is not practical to shut off the water in this case. Condos with no separate shut off so has to be scheduled through the HOA to shut everyones water off.
 
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Old 07-22-11, 08:20 PM
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Update: I got a small O-ring for the compression cap, fitted it, and it works well. Had the valve open for about 10 hours now with no leaks.

Is this a good permanent solution? Is there any worry that the o-ring will be compromised by the heat of the water, or anything else I haven't thought of?

Thanks for the help everybody.
 
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Old 07-22-11, 09:13 PM
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The o-ring and cap is a semi-permanent repair in that it can be removed if ever need be. If not disturbed it should last for many years, probably until the building is torn down. The hot water will have no effect.
 
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Old 07-23-11, 05:17 AM
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Long term fix, I still say buy a valve with one less outlets, tie a string to it and around the existing valve. If the HOA ever decides to do work on another building and notifies you of water cessation, run down, take 45 seconds to retrofit the valve and have it done right. I'd also install a ball valve ahead of this, or at the water entrance so I could turn my unit off separately from the others.
 
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Old 07-23-11, 06:57 AM
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Not sure how long you going to live there but you might want a DW again, or a new owner if you sell.

The correct way would be a tee on the end and have two valves. Also put main shut offs wherever you can when and if they ever shut the main off.


Just a thought.


Mike NJ
 
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Old 07-23-11, 04:39 PM
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Thanks for the replies, guys.

I'll just leave the cap on. I was only worried that it might bust off or melt or something else catastrophic and flood my kitchen. Sounds like that's not a concern.
 
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Old 07-23-11, 05:06 PM
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Hi, Just wondering does the HOA supply the hot water for the Complex? If not esvoytko has his own hot water heater and most likley a shut off valve for the heater and thus may be able to shut off the hot water and replace the valve.
Good Luck Woodbutcher
 
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Old 07-23-11, 06:31 PM
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Originally Posted by Woodbutcher View Post
Hi, Just wondering does the HOA supply the hot water for the Complex? If not esvoytko has his own hot water heater and most likley a shut off valve for the heater and thus may be able to shut off the hot water and replace the valve.
Good Luck Woodbutcher
Yeah, but we try to avoid the easy and obvious answers.
 
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Old 07-25-11, 01:00 PM
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Before I became an expert plumber (heh-heh-heh-hehÖ) I lived in a condo and had a drip under the sink. There were 20 units in the building and there were no individual shutoffs for each unit. So you had to have the HOA notify everyone of a time in writing and shut off the water to the entire building.

Well, I figured I could just back the nut off a little and a put a little extra Teflon tape on the threads (oh yes I did!) and who needs to shut the water off. Thatís when I first discovered how good city water pressure is. The nut came off and a stream of water shot way out into the dining room. I thought I was going to need a life jacket. Just like curly of the Three Stooges I was fighting the current trying to get the nut back on. But I figured out soon I might drown first so I called our emergency maintenance number.

Turns out our complex maintenance guy George who was a crackerjack was there in a only few minutes. (George reminded you a lot of Norm on This Old House and was just as smart!). George had one of those companies come in with big fans for the weekend and I saved all my carpets. No permanent damage. It was a slab foundation.

I can appreciate all the care thatís being taken here! (Of course I donít imagine anyone would be as dumb/crazy as me! lol)

p.s. This is not a plumbing issue but a point about insurance. Our HOA had insurance on the entire building. The residents would just insure the contents of their dwelling. I installed wall-to-wall carpets. Turns out the building insurance did not consider wall-to-wall part of the building, but the contents insurance did not consider wall-to-wall as part of the contents. I guess you need a special insurance rider for wall-to-wall carpeting? But just makes you realize that if you live in a condo make sure nothing falls through the cracks in terms of insurance!
 
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Old 07-25-11, 02:44 PM
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Well I can top you. A customer needed a new ballcock. I thought I'd make a quick buck on the way home after completing another job. Simple, quick job, Right? Shut the supply valve off, replaced the ballcock. Everything was going smoothly. Went to turn the supply valve on and it popped of the pipe and into my hand. Dang PVC and I guess a bad glue joint just waiting for me. So I yell where's the main cut off and the guy leads me to the garage, points to a heavy steel plate screwed to the wall and says behind there. That job cost me over $300 and taught me to never work on PVC piping without turning off the main valve.
 
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Old 07-25-11, 02:56 PM
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I tried to change a upstairs toilet supply without finding the main shut off. Soulds simply right. It was old threaded nipples on the valve going into the floor

. What do you know, "snap"!!!. Could I just say I held my thumb on that valve for 5 minutes at least while I yelling from the second floor for the lady to turn the main off. She did not even know what she was looking for...LOL

It was a mess. And I was taught years ago not to disturb this type of piping or try to turn valves without turning off the main because this happens.

Mike NJ
 
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Old 07-25-11, 06:31 PM
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Maybe Hollywood gets this stuff from real life. lol
 
 

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