We have a 5-year old home with a gas water heater. There is a lot of corrosive-looking material (rust colored flaky stuff :rolleyes: ) where the 3/4" copper house plumbing is connected to 2 steel or some other metal (not copper) pipes coming out of the water heater.

I'm not sure that is very clear. In other words, there are two pipes coming out of the water heater that are made of some metal other than copper. They are about 8" long or so. The 3/4" copper cold water supply is connected to one of them with a threaded fitting. On the outlet side, another 3/4" copper line (house supply hot water) is threaded to the other pipe coming out of the water heater.

I'm assuming the two metals do not agree with one another and that is causing the corrosion.

Assuming that is correct, is this just a simple matter of removing the dissimilar metal pipes and replacing them with copper? There are no shut-offs plumbed in either so I would want to add those. Would 1/4 turn valves be appropriate?

Thanks for any advice.

Hi Augy:

Sounds like brass nipples connected to tank tappings and threaded copper adapters. 8" is too long for dielectric nipples (see pic.)...

If you really want to save this water heater... I would replace those nipples with new dielectric nipples (teflon tape these in) and I would also change the anode rod and flush the system (see other pic... pic. Is of a new VS old anode rod... betting your looks like the bad one).

Be aware that by disturbing system at this time, tappings may fail and water heater may need to be replaced... rare, but never know.

How much of this can you do..

Let me know what you think... Mark

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Quote:

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Originally Posted by massplumber2008

Hi Augy:

Sounds like brass nipples connected to tank tappings and threaded copper adapters. 8" is too long for dielectric nipples (see pic.)...

If you really want to save this water heater...I would replace those nipples with new dielectric nipples (teflon tape these in) and I would also change the anode rod and flush the system (see other pic....pic. is of a new VS old anode rod...betting your looks like the bad one).

Be aware that by disturbing system at this time, tappings may fail and water heater may need to be replaced....rare, but never know.

How much of this can you do..?

Let me know what you think...Mark

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That sounds like what I'm looking at. I am going to try attaching a picture (should have done that to begin with). I am pretty comfortable with copper plumbing so I think this is something I can do but I just need a little clarification on a few things.

Should I install shut-off valves? Would doing so require a third shut-off valve and a bypass line between the inlet and outlet pipes?

Is a "dielectric nipple" labeled as such (at Lowe's, HD, or similar store)?

What length of nipple should I use (or just the shortest possible?)

Does the teflon tape not only seal the fitting but also act as a buffer between dissimilar metals?

I would want to make this as easy as possible and avoid as many sweats as possible. If I start at the W/H and thread in the nipples, then thread a copper fitting (theaded on one end and sweat on the other), and sweat a small section of copper pipe to the existing lines (after cutting out the corroded threaded fittings)... would you recommend a simpler alternative?

Thanks for the reply, I really appreciate the advice.

Now, to see if I can add a picture or two. It's hard to tell but the section between the nipple and the copper is a silver-colored metal material.

Maybe you can wire brush those fitting and repost another pic. Looks like all copper to me.

Hi Augy:

You have type M copper tubing there.. that is not helping here (thin walled pipe.. reserved for heating pipes.. not for water! ).

I would shut water main supply off at water meter... replace the cold water shutoff (I can see type M corrosion in pic.)... then remove the long nipples in place and the type M pipe copper pipe around 12-18 inches off the water heater.

Teflon tape will not do much in terms of dissimilar metals. Type L copper tubing (for water piping), new dielectric nipples (sold at all home supply stores..clearly marked..whatever size available)..will make the difference.

No bypass needed... no hot water shutoff needed.

Did that all make sense..

Quote:

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Originally Posted by massplumber2008

Hi Augy:

You have type M copper tubing there..that is not helping here (thin walled pipe..reserved for heating pipes..not for water!!).

I would shut water main supply off at water meter....replace the cold water shutoff (I can see type M corrosion in pic.)...then remove the long nipples in place and the type M pipe copper pipe around 12-18 inches off the water heater.

Teflon tape will not do much in terms of dissimilar metals. Type L copper tubing (for water piping), new dielectric nipples (sold at all home supply stores..clearly marked..whatever size available)..will make the difference.

No bypass needed...no hot water shutoff needed.

Did that all make sense...?

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Yes and no :) I'm not familiar with different types of copper (Type M vs Type L) but I can be educated. How can you tell the difference (especially from those pictures?)

I do see now that I only need to replace the cold water supply shut-off valve. Should I use a quarter-turn valve? Threaded or sweat?

Just a few more questions...

I assume the dielectric nipple is threaded on both ends. So, do I use a threaded copper fitting on top side (away from the W/H) and does that require teflon tape? If so, should that fitting be threaded to the nipple and sweat on the other side?

I'm sure I'm over-thinking this and it sounds pretty straight-forward. I just want to minimize trips to the hardware store and try to have everything ready when I turn off the house supply line.

Thanks again for the help.

Here is a picture (first picture) after using a scotchbrite pad to clean it up a bit...

Looking at the existing shut-off valve, there is only about an inch between it and a "T" fitting. Can I successfully heat up the shut-off and remove it without ruining the "T" fitting just above it? In other words, I'd like to save the "T" fitting and just replace the shut-off valve with another valve. Any suggestions? You can see this in the second picture.

Thanks for the clean up, its starting to look like a galvanized pipe if its silver and that would certainly explain the corrosion. Mark and I frequently agree and probably could nail this better if we could see with our own eyes. Mark is thinking thin walled copper and I'm thinking galvanized nipple, its all in the color of the picture. Another option would be to install a copper flex line between the tank and the rigid cooper female adapter. I don't think you are going to save that Tee so just buy a new one. If I am wrong you'll have a spare but I think the TEE and the valve are going to heat up about the same amount. Don't take the chance.

Quote:

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Originally Posted by ballengerb1

Thanks for the clean up, its starting to look like a galvanized pipe if its silver and that would certainly explain the corrosion. Mark and I frequently agree and probably could nail this better if we could see with our own eyes. Mark is thinking thin walled copper and I'm thinking galvanized nipple, its all in the color of the picture. Another option would be to install a copper flex line between the tank and the rigid cooper female adapter. I don't think you are going to save that Tee so just buy a new one. If I am wrong you'll have a spare but I think the TEE and the valve are going to heat up about the same amount. Don't take the chance.

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Thanks for the responses. You suggest a "copper flex line". Can you clarify that? I'm not familiar with anything in 3/4" copper that is flexible (I can surely be educated though!). If I understand you correctly, you are saying I can re-use the the threaded fitting on the hot side (the fitting that is located about 10" or so above the tank). I can see that the supply side "T" is going to have to be replaced as you suggest. Oh well, just one more sweat fitting.

I don't know why sweat fittings have become such a pain for me in the past few years. Could it be something to do with the move to lead-free solder? I've only got a propane torch. It just seems that a few years ago I had no problem getting things good and hot but the last few times I've sweated fittings, it just seems to take forever to get the joint hot enough to melt the solder. (Sorry, I might have got a bit off topic).

Thanks again for all the advice.

Flexes:

Take a look here: Stainless steel flexible lines - The PlumbingStore.com

Note the corrugated copper flex lines.

Propane works for me, but now I know why mp uses MAPP gas. Faster. I find the lead free solder easier to work with. Problems are mostly on the preparation and making sure there is no water in the joint. Learn to solder with the fitting sitting on top of the pipe.

Hey Augy:

I see these guys have been helping you. Great information, as usual!

I can tell it is type M (thin walled) copper tubing in the first pic. Because the copper tube has a RED stripe... that red stripe tells me it is type M copper tubing (Typle L copper tube is blue line).

I would be able to save that tee, but do yourself a favor and get a new 3/4" copper tee AND a 3/4" copper coupling in case you can't. The trick on this is to clean the old fitting and shutoff, flux it up, then heat middle to top of valve (primarily middle) and then when solder starts to pop a little, twist and pull down and off. Then reheat the joint a little more and wipe the joint clean. Sandpaper this joint when cooled, flux it and then solder a new 3/4" copper BALLVALVE in place. If that doesn't play out for you...just cut the tee out, attach couplings, new tee and new shutoff.

From there, well...depends on what you do. The corrugated flex lines Ballenger and KISS suggested work great, allow flexibility and allow for easier installation of the NEXT water heater..;)

Still need to solder at a spot or two though. ALL fittings that are to be soldered and then teflon taped must be PRESOLDERED onto copper tube (and cooled) BEFORE applying pipe dope or teflon taping anything.

Depending on which flexi. you go with..will need 3/4" copper male adapters and those 3/4" dielectric nipples (see pic)... these are short and help reduce the electrolytic effect between nipples and tank tappings.

In terms of soldering... YUP! Kiss said it.. I like MAPPGAS system... burns super hot (propane or acetylene)... AND when I have apprentices solder for me I ask them to do the following:

Shut off main water shutoff to the house. Open all faucets in the house and the outside faucets as well. If laundry tub in basement open faucets there, too (may even need to diconnect washing machine hoses and drain those, too. Then you will need to drain 5 gallons or so of water from the water heater so water is well below where you will be soldering... Then, only then, can you solder (if any water is issue after this, then main shutoff may not be working and you may ned to unhook your water meter and let drip from there while soldering).

After complete job, turn off all faucets, reconnect all, and then turn on water main... NOW, fill the water heater and then go to laundry tub and open faucet to bleed system.. then next, open the TUB upstairs, and continue to purge air/sediment from the lines up there (no aerators here, so less chance of clogging faucets). Once tub runs clear can start to purge other faucets of air/sediment and should be all set to go!

*Whew*.. you think you went off track... huh? ;)

If you have any other concerns... let us know. One of us will follow up with you soon! Good luck... Mark


If this helped please RATE THIS ANSWER. Thank you.

Ok, I have seen those before. One end sweats to the copper pipe and the other threads onto the nipple? That looks pretty simple. I'll try to pick this stuff up this week and get it installed. I'll post back with the results. Thanks.

massplumber2008, thank you for the reply. I will certainly buy plenty of parts and plan to return what I don't end up using :) Good info there... thanks.

Anyway, I stopped over lunch and had a good look at what's available at the chain stores. I then came home and really looked over what I need to complete.

I just have a few questions left (I promise... then I'll just get on with it!)...

HD sells compression-type fittings called Shark Bite (I'm sure you're familiar with these). In lieu of sweating fittings, could I use the Shark Bite Fittings? They are pricey so it might be smarter to buy a new Mappgas soldering kit... thoughts?

Also, a 10' length of Type L 3/4" copper is the shortest they sell and it's $34!!! I need about a foot! They have 5' pieces of Type M but from what I understand I don't want to use that...correct?

Using Shark Bite...could I use PEX tubing rather than copper or is that inviting trouble?

The chain stores all sell the corrugated steel and/or copper flex hoses (finally found them with the water heaters). They also sell braided stainless steel hoses that say they are for water heaters. These are more flexible but are they a good option?

Lastly (I think)...the shortest lengths of the flex connectors is about 12". I only need about 8". I'm afraid the 12" or 15" connector would be overly stressed to fit in that space. So, I figure I'll just cut out more of the house 3/4" copper pipe. The only other idea I could come up with was to put an elbow about 8" above the W/H and use long (24" or so) flex connectors and kind of loop them up and around to make this connection. Does that make sense?

Again, thank you all for your help. I'm really sorry for all the questions... just want to get this done right the first time.

I'll take a couple of them:

Look for the copper tubing at a mom and pop hardware store. I have a true Value nearby and they sell shorter lengths.

One thing that you may have overlooked is the use of couplings and unions.

Couplings

They come in two varities:
1) With a stop in the center (could just be a dot)
2) Without (For putting pipe together)

Unions

It can be used and it offers the option of easily fixing the pipe fittings if they leak. On the negative side, you would have to use two and most likely temporarily remove the gas line.

In any event, I see you having to so the following:

1. turn off the water heater
2. Turn off the main water supply
3. Drain the cold and hot water lines
4. Drain the hot water lines
5. Drain some of the hot water out of the tank from the bottom.

6. Cut the inlet and outlet in two places or cut in one and move the water heater slightly.
This may involve shutting off the gas to the house or the appliance. Pay attentntion to lengths.

7. Remove shut off valve.

8. Install shutoff valve with a new piece of pipe and a short extension of pipe.

9. attach temporarily and measure the length of pipe required to the valve.

10 Cut.

11. Teflon tape the Female adapter and dialectric nipple finger tight + 2 turns. Use only two wraps of tape and don't tape the first thread. Tape in the direction of tighten.

12. Put the coupling on without the dent.

13. Do essentially the same process on the outlet without the valve and don't forget the coupling.

14. Move the pipes in place.

15. Mark where the coupling goes and add about 1/2" to each side.

16. Move the water heater in place.

17. Put something to hold the coupling in place like a vise grip.

18. Solder. And hope you don't have a leak at the water heater.

You can use a union rather than a coupling if your scared. You can then take it apart again if it leaks.

You MUST NOT solder close to the water heater because of the plastic linings.

Maybe not quite right, but I hope you have the idea.

9.

Thanks KISS, I would plan to use couplings if I sweat this all together. I'm just wondering if those shark bite fittings and some PEX tubing would work and be a reliable solution. That would allow me a lot more flexibility in aligning everything (and save me a lot of sweating headaches using my propane torch and (apparently) less-than-stellar sweating skills!).

Regardless, I plan to install the short dielectric nipples to the tank, then use the flex hoses (still curious if corrugated steel vs corrugated copper vs braided makes much difference) to connect the nipples to the hard plumbing with male fittings either sweated or compression-fitted to the 3/4" copper house pipe.

In the end, I want to do what is best so whatever you guys say is the way to go I will heed your advice.

Quote:

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Originally Posted by augy123

Regardless, I plan to install the short dielectric nipples to the tank, then use the flex hoses (still curious if corrugated steel vs corrugated copper vs braided makes much difference) [connect the nipples to the hard plumbing with male fittings ] either sweated or compression-fitted to the 3/4" copper house pipe.

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Steel and braided are not the same material as copper, so corrugated copper probably makes the most sense.

The sentence fragment enclosed in []. You connect nipples (male) to a "3/4 sweat female adapter".

I hate compression fittings.

"and/or copper flex hoses (finally found them with the water " that was the pipe I referred to many posts ago. It may be the best opion if you don't like to sewat pipe.

Sorry guys, I'm probably making this an unreasonablly long thread. I'll just grin and bear it and sweat the proper fittings. Sounds like the sharkbite fittings aren't a good solution.

I am having trouble removing the nipples. I started with the hot side and cut the copper off. I'm trying to remove the nipple and it won't budge. I'm afraid I might damage the w/h where the nipple threads in if I pry too hard.

Any suggestions. Thanks.

"Pry"? Corrosion is nasty stuff. Remove as much of the rust as possible at the fitting with a small wire brush. Wd-40 can help. A pipe wrench will give you a grip to turn.
If you have to, turn slightly in both directions