I'm at my wits end with this corrugated copper pipe. How to stop this leak?

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Kreemoweet

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No ones's mentioned yet the possibility that the male adapter has a leak in its threads . . . this could happen if the copper
was not quite thick enough to support the depth of the threads cut/formed in it, somewhere in that threaded area. It seems we're running out of options here . . .
 

SonOfGloin

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10 wraps of teflon and a moderate tightness - pinhole leak is still there, but very slow. The universe is allowing me a shower, or at least in an hour or so.

I'm going to take this opportunity to do hot water things that have been put off (e.g. laundry, dishes). This buys me some time to settle on a proper solution.

What do you all think is best? Go with the brass bushing combo? Or sweat a new MIP adapter in place? If the latter, then does this part exist in a higher quality version that you can recommend?
 
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John Gayewski

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Sure seems to be compressing nicely against the washer:

View attachment 91202

The copper also doesn't have any deep scratches.

I'd be surprised if the male adapter doesn't have enough threads to adequately compress the washer. The other line is attached to the same adapter, and it sealed perfectly on the first shot (hand tight, plus moderate wrench turn). This non-leaking joint isn't threaded as far as I've been able to go with the bad one.

I'll try the two washer method again.

Also, for what it's worth, I got it down to a pinhole leak with 8 wraps of teflon
The washer in this picture is ruined. They get ruined by over tightening. I would say replace it, but sometimes replacement washers don't fit as well.
 

Fitter30

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Look at the threads in the brass nut their finer than the mpt and there not tapered. The fitting is made to seal at he end not the threads. A mpt adapter end isn't a machine surface.
 

Tuttles Revenge

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It was mentioned that the threads on the water heater, which are pipe nipples didn't leak. I would be inclined at this point to install female adapers and a short nipple to thread the flexes to.. Or they make flexes that solder on one end and threads on the other (I don't like those personally...)
 

Reach4

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1. Does that washer have a round cross section? Maybe go to your local big hardware store, and see what washer they would have and try one of those.
2. When you lift the washer out, is the place the washer seats against, on the flex line, damaged?
index.php
 

WorthFlorida

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SonOfGloin, where are you with this? I would ditch everything since all the threads are deformed.

Brass to brass tape or pipe dope is generally not needed. Brass to anything else tape or pipe dope is needed. Use no more than a pea size dope of pipe dope and not on the threaded ends. When there is a tiny leak, like a weep that might drip a little, let it sit for a day or two and keep a rag around the pipe. The little weeps will usually self seal from the minerals in the water. When using a flex pipe tighten to a snug fit. When it feels like it bottomed out at the washer, give it a 1/4 turn. if it weeps some, give it a little more. Just came across an article on FB by a house inspection outfit. Number one plumbing error, over tightening fittings.

In your case change to push and fit or Sharkbite fittings. They have a 3/4 male threaded end of for the water heater, the other end a press and fit. At the copper pipe, a regular press and fit coupling. For pipe use copper or CPVC. Millions of homes use CPVC and nothing wrong with it. Are you adding an expansion tank? The first picture is my home, the second at my church, third at my son;s house. All three done in three month period.

1678307161889.jpegIMG_6813.JPG1678307273933.jpeg
 

wwhitney

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Brass to brass tape or pipe dope is generally not needed.
Huh? Any tapered threaded joint that is intended to seal requires teflon tape or pipe dope, because of the possible spiral leakage path. While you may have success simply tightening them enough to deform the brass to seal, that is not the intention, as I understand it.

The IPC calls out "Pipe-joint compound or tape shall be applied on the male threads only." This is in the section on "copper alloy tube" joints, which I understand would cover brass.


Apparently people who like to use tape on the male threads and dope on the female threads are violating the IPC. : - ) But I guess you could put tape on the male threads and dope over that, if that's the way you like it.

Cheers, Wayne
 

Eman85

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@WorthFlorida I see you're not brand loyal. Which of those heaters if any did you think were better than the other? I see you connected CPVC direct to the heater, I thought it needed metallic lines. On the one it looks like you have the valve that mixes hot/cold and you turn the water temp up, how is that working?
 

SonOfGloin

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Hi all,

My apologies for going AWOL on this. Having the pinhole leak almost seal itself (at least to the point where there wasn't perennial dripping) afforded me the opportunity to move on to other pressing projects, but fully fixing this has been on my to-do for months.

Here's where I am: The pinhole leak on the hot side has crusted over which continues to grow, while the cold side still maintains a perfect seal.


1.jpg


I've grown interested in the idea pitched earlier in this thread to use brass fittings on which the flex pipe would form a better seal. So, is the idea to remove and toss the old flex pipe and clean the existing sweated-in copper mpt threads with a brass brush, then thread in some sort of brass bushing combo that will allow me to thread in a male 3/4" brass nipple, using pipe dope on all of these threads? Then the flex pipe should seal much better against this? If so, would I start with a brass 3/4" FIP x 1" MIP bushing, followed by a brass 1" FIP x 3/4" FIP reducer, then a 3/4" x 3/4" brass nipple?

I also have to ask, in parts of the country where local code requires flex pipe, what's the standard way of setting this up using only threaded fittings? I ask because this flex pipe is used to often that I expect my issues to be commonplace.

Also, I'm getting significant corrosion on the cold side nipple. It started within a few weeks of install. Should I change the nipples out in favor of brass?

2.jpg


Finally, I also have a pinhole leak at the expansion tank:


3.jpg


I'm guessing this was improper, relying on teflon tape to make the seal. Any suggestions on remedying this? This one is tricky since I supported the expansion tank with a quick strap that's mounted to the wall with tap cons. So if I do a similar setup above with brass bushings, it would lower the tank to the point where I'd have to remove and reinstall the bracket. Can I just clean the threads and reinstall the tank with pipe dope?

As always, shared thoughts and expertise are deeply appreciated.
 

Jeff H Young

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remove tank clean off threads use pipe dope and tape. the water heater change the nipple and possibly the flex line
 

Jeff H Young

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I like flat washers too. the o ring type I never see on the water heater flex and would avoid I almost never change a washer If I got a leak on an old flex line it goes in trash if its a new line they almost never need changing
 

SonOfGloin

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I think the flex pipes came with flat style washers already installed. Actually, back in March when I was originally doing this and constantly removing (and occasionally replacing) the flex pipe, I picked up the same pack of replacement washers that @Kreemoweet linked. Still leaked
 

Reach4

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Silicone grease on rubber washers and seals helps. On the threads too.
 

Jeff H Young

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keep trying but in mean time remove that rusty nipple and dont use tape on the threads
 

SonOfGloin

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Okay, I think I'm going to try one of @wwhitney 's earlier suggestions and make it so that the flex pipes thread to brass mpt, keeping the existing copper 3/4" mpt and using a coupling and a nipple. That is, the transition will look like the following:

(Existing 3/4"copper mpt) --> (3/4" brass coupling) --> (3/4" close hex nipple) --> flex pipe.

Note that the red arrows above denote where I will use tape/dope. This is the coupling I'm planning to use:


brass-fitting-lf-coupling-075.jpg


And this is the nipple:

CloseHex.png


Further, I'm thinking about ditching the Home Depot/Lowe's flexible lines and using Falcon Stainless' Extra Flexible Mega-flow ULTRA Flex line:


stainless-water-heater-extra-flexible-flex-075fips-075fips-18.jpg


My rationale here is that greater flexibility will make it easier to ensure that the washer is sealing flush and there's no tension pulling the threaded portions in any direction. The regular flex pipe is difficult to get to align perfectly.

How does this plan sound?

Second question, about that WH nipple: Why did it corrode like that? I thought the plastic-lined nipples on new WHs prevent this. I've never changed WH nipples before: are they attached to anything inside like an anode rod? Or can I just pull them out with a pipe wrench and thread in a pair of brass nipples? Also, what length nipples are appropriate. The WH is an A.O. Smith signature 100.
 

Reach4

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I thought the plastic-lined nipples on new WHs prevent this. I've never changed WH nipples before: are they attached to anything inside like an anode rod?
Some hot nipples are combined with the sacrificial anode rod.
 
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