How To Repair a Galvanized Pipe Using Dresser Couplings

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Repair any plumbing pipe with these easy to use fittings


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Dresser couplings are a style of repair coupling used to splice plumbing pipes. They are used on galvanized, pvc, and abs drainage lines, copper water lines, pvc and cpvc water lines, and galvanized water lines. If a water line freezes and breaks, you may not be able to repair it with a brass compression fitting or a fitting from the same material as the pipe. In a case like this, try a Dresser coupling. Sometimes on old galvanized water lines the threads are corroded to the point of uselessness and you cannot rethread the pipe. You may be able to use a Dresser coupling here to repair the line if it is not corroded as well. As you can see, they are a versatile repair fitting.


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Preparation – Choose The Right Fitting

Dresser couplings come in two types, galvanized and plastic. Both types are basically a sleeve sized to slide over a particular size of pipe. The sleeve is threaded externally on both ends and comes with two threaded nuts, one for each end. Inside each nut there is a molded rubber compression ring. One edge of each rubber ring is beveled. The beveled end must be installed toward the center of the sleeve to match the bevel inside the end of the sleeve. Inside galvanized Dresser coupling nuts there is also a metal friction ring. You must use this ring when you assemble the Dresser coupling during a repair otherwise your repair is almost certain to leak.


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Install the Fitting

To use a Dresser coupling, just cut the pipe where you need to repair it, slide the nut and rubber compression ring over the end of the pipe in that order and push the nut and rubber compression ring down the pipe at least the length of the sleeve. Now slide the sleeve over that same end of the pipe. Slide the second nut and compression ring respectively over the opposite end of the pipe you cut. Center the coupling sleeve over the cut you made in the pipe. Work one rubber compression ring toward the coupling until it seats inside the sleeve. Make certain it seats squarely and firmly. Slide the nut up in place and hand tighten it. Do the same for the second rubber compression ring and nut. Once both nuts are hand tightened, using one wrench on the body of the sleeve, use a second wrench to tighten both nuts. If the Dresser coupling is plastic use two pairs of water pump or channellock pliers instead of pipe wrenches and do not over tighten the nuts or they will crack. You can use pipe wrenches on the nuts if they are galvanized.


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Tips and Tricks

There is one caution to observe when using Dresser couplings. Both ends of the pipe to be repaired must not have any horizontal movement at all. If there is horizontal movement on a horizontal pipe or vertical movement on a vertical pipe, that pipe must be restrained or use a different type of repair fitting. If the pipe is underground this is usually not a consideration unless the system is under high pressure. If the pipe is in a crawlspace or basement, the pipe must not move at all or the Dresser coupling will leak or even blow apart.

Dresser couplings are easy to use

Dresser couplings come in a variety of sizes and from different manufacturers
Dresser couplings come in a variety of sizes and from different manufacturers

Comments 23 comments

Wal-Rich Corporation 7 years ago

Other important things to consider when using Dresser couplings:

1. Line content: This is the material flowing through the pipe. Important to know so that the gaskets can be suitable for the application. (i.e. oil, water, and steam require different gaskets)

2. Temperature: Same reason. Gasket integrity must be maintained.

3. Pressure: Couplings are manufactured to ANSI standards, and for higher-pressure applications, you may need a heavier-pattern coupling.

4. Pipe Outside Diameter (OD): Critical to know! Dresser couplings seal on the OD of the pipe, and different types of pipe have different OD's (i.e. Steel, Copper, Ductile Iron)


Jerry Watson profile image

Jerry Watson 7 years ago from Hermitage, Tennessee Author

Exactly right. Thanks for the addendum. While this article is directed to residential applications, I didn't specify that properly. I appreciate your input!


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elf_cash 6 years ago

Great Hub Jerry, special kudos to Wal-Rich Corporation for that nice addendum. I was thinking about temperature concerns as I read through the information but Wal-Rich hit it right on the head. Overall this is a really good resource for the weekend warrior, it takes a lot of the guesswork out. I'm new to hubpages but I plan on lending my plumbing expertise to the community as well. Again good job.


Ron 6 years ago

I want to use this type of coupling to patch an underground pipe that goes to a hose bibb in my back yard. Since the pipe is under 12 inches of soil, it won't move. The directions seem to indicate that during installation, you have to be able to move one side of the cut pipe enough so you can slip the coupling over the pipe. Do you have to dig out the pipe far enough so you can move it? Or can you cut out a section of the pipe wide enough to fit the coupling in but narrow enough to provide a seal in both compression fittings?


ac 6 years ago

wHAT IS THE BEST WRENCH TO USE TO TIGHTEN A PVC COMPRESSION COUPLING ON A 4" PIPE. iS THERE A SPECIFIC TOOL THAT CAN ACCOMMODATE THAT CIRCUMFERENCE?


Jerry 6 years ago

Hi AC,

Thanks for your question. There are a number of tools that will work for pvc compression couplings. The primary factor is that too much squeeze force will distort the coupling nut making it seem tight when, in reality, it is still loose enough to leak. So, first tighten the nut as much as you can by hand; then you can use a large pair of Channellock or waterpump pliers if you don't squeeze the handles together any more than necessary to grip the nut. A suitable size pipe wrench will work too if the jaws are not excessively worn; Keep the pipe wrench jaws positioned over the back of the nut, not the front or open end. A strap wrench is another good choice. Also, the nut must not be over tightened because you can split it if you do. Tighten the nut until it stops or until it is snug; then turn on the water and check for leaks. If necessary, tweak the nut slightly. Even better, de-pressurize the line, loosen the nut and reposition the gasket, re-tighten the nut and recheck for leaks under pressure. For a coupling on a four inch line, you probably should use a large 24" or larger pipe wrench or a large strap wrench. Another good choice that just came to mind is a spanner wrench. This wrench doesn't have a jaw; it is just formed in the shape of the letter "C" with a small hook on the far end that catches the ridges on the nut allowing the operator to tighten it. The spanner wrench may work on some makes of compression coupling nuts and not on others. Patience and attention to detail will help you solve the problem. Good luck and thanks again for reading my posts.

All the best,

Jerry


alex 5 years ago

pvc dresser,how long can they last once installed?


plumbing 5 years ago

Thanks for the advice,knowing this tips helps us to look for alternatives that we can use in order to repair and save a little money for the service.


Jerry 5 years ago

Hi Plumbing and Alex,

Thanks for both your comments. Sorry I missed yours, Alex. Basically, pvc couplings will last a very long time if they are installed correctly and are not exposed to sunlight. Glad to be able to help, Plumbing.


Ron Q 4 years ago

I have an old house with no shut off valves under the kitchen sink. Can I use a dresser coupling and go from galvanized steel to copper?


Jerry 4 years ago

Hi Ron,

If I could suggest a better more permanent fix for your particular situation: strip out the old galvanized pipe back to a solid threaded joint; then screw in a pipe nipple and install a dialectic union which will allow you to transition from galvanized to copper pipe while preventing the build-up of electrolysis which will damage the water line. Sweat in the copper pipe you need and install an escutcheon and sweat or compression stop under the sink and you're done. Thanks for reading. http://JerryLWatson.Wordpress.com; http://theantiquarianchronicles.blogspot.com


Plumbing San Jose 4 years ago

Very efficiently written information. It will be valuable to anybody who utilizes it, as well as myself. Keep up the good work – can wait to read more posts.


Jerry Watson profile image

Jerry Watson 4 years ago from Hermitage, Tennessee Author

Thanks, Plumbing San Jose. Appreciate it!


Paul W 4 years ago

Sorry, this is a long post, but don't skip it and waste a lot of time like I did.

I'd like to add two more tips.

1. Make sure the pipes you're joining are almost perfectly aligned. I learned that the hard way. If you want to skip the long story, go to tip # 2. I tried to use this type of coupling on a water pipe underground near the water meter. I spent about an hour on it (draining the pit (this was after excavating, discovering what I needed, going to the home center, etc.), measuring and cutting the pipe, cleaning both ends of it, etc.) When I was done, I turned the water back on and about 3 seconds later (when enough pressure was restored) I heard a small pop and "spritz!" (or whatever the sound of water spraying is), right at my face. Unfortunately, I had started late in the day and it was starting to get dark; no time to fix it. So I spent a night with egg on my face and a night without water. The next morning I could clearly see that the whole pipe assembly from the meter to past the new coupling was not straight; it was crooked both sideways and horizontally; and I could see that where the pipe went into one end of the coupling was askew. I had to drain it again, take the coupling apart, use two short pieces of lumber to hold the pipe straight, clean the pipe again, and clean the coupling, and reassemble it.

2. Even though it's not necessary with this type of coupling, it won't hurt to use teflon tape; but never overuse it (no more than 3 times around.) This tip I got from an employee of the home center, and he wasn't trying to sell me any tape; I had told him I had some at home and asked if I should use some.


Jerry 4 years ago

Thanks, Paul, for your comment. I'm sorry to hear about your experience but it sounds like you got it rectified okay. I hate to have to contradict your advice from a big box store employee but it's not a good idea to use Teflon Tape in this application. Might work, might not. It's better to use the fitting in the manner intended by the manufacturer. If you feel like you need to add a lubricant to the threads use silicone lube (food grade) or a neutral oil like mineral oil or, even better, baby oil. Be aware that certain compounds can damage or destroy the gasket material so don't use petroleum based products as lubricants. Some pipe joint compounds may work well too. Check the compatibility of the product before use. Once again, thanks for reading and commenting, Paul. Your patronage is greatly appreciated. Check out some more interesting reading and information at: http://JerryLWatson.Wordpress.com or http://theantiquarianchronicles.blogspot.com


Paul W 4 years ago

Jerry, thanks for letting me know about not to use Teflon tape on this type of application. I'll remember that next time. The guy at the home center store sure sounded like he knew what he was talking about, but I didn't ask him if he was ever a licensed plumber. Sorry, fellow readers; disregard tip # 2 above.


Jerry 4 years ago

Hi Paul. Nice to hear from you again. Glad to be able to help!


Quincy 4 years ago

Questions: I excavated my leaking sprinkler main water line, and found the leak. it is old galvanized pipe, and it is on a potentially very long straight edge run on the side of my house to the backyard, underneath a ton of tile and concrete, which I hesitate to demolish to expose the whole pipe run. I hope to apply the dresser coupling to repair the leak. Question is..i've spotted another leak about 1.5 feet from the first leak...so in this case, would you recommend using 2 dresser couplings? With the constant pressure from the main water supplied on this run, will this coupling be sufficient? Thanks.


Jerry 4 years ago

Hi Quincy, and thanks for your comment. Congratulations on finding the leak(s). First off, repairing that old galvanized pipe may present a problem because of severe corrosion on the surface of the pipe which is what the dresser coupling makes a seal on. The best I can advise without seeing the job first hand would be to excavate the pipe carefully until you expose a threaded joint such as a coupling which you might be able to find in a long straight run such as you describe. Then try to unscrew the coupling or rather the old pipe from the threaded joint (cut the pipe on the bad side of the joint first), screw in a new adapter fitting to, say, pvc and run a new pipe segment. You could try to clean the surface of the pipe where you intend to install the dresser coupling and see if it will seal properly first. Good luck with your repair and thanks for reading.


Rick K 4 years ago

So, the underground galvanized water supply pipe into my house has sprung a leak just a couple of feet inside the foundation . I dug it up and have it temporarily patched. The plumber I hired for a consult suggested digging up part of the line outside the foundation (to find a fitting) and bypassing this leaking section. Sounded good, but on further review, the drilling will most likely kill the fabulous Japanese maple I have out there. So I need alternatives, and this dresser fitting seems to be viable. Given that my home-made rubber and hose clamp patch is holding pretty well, would you expect that a galvanized dresser coupling would work OK in this service?


Jerry 4 years ago

Hi Rick, Yep, the dresser coupling is made to order for just such a repair. Sounds like the plumber you consulted is on the right track as well but I can understand not wanting to risk the health of the Japanese maple tree. Maybe if it is not to big it could be dug up root ball and all and laid aside until the repair is done and then replant it. As far as using the dresser coupling is concerned, be careful to examine the galvanized pipe after cleaning it as well as possible to make sure it is sound enough to work with the coupling. After gently scraping all the mud and dirt off the pipe surface take a strip of emery cloth and clean the pipe surface where you expect to install the coupling and then examine the pipe carefully. If it is reasonably sound install the dresser coupling and you should be good to go. One other note: mark the location of the coupling and file it so you will have it in the future if needed. Good luck! And thanks for reading.


Moshe 3 years ago

Hi Jerry wanted to know if u can use a cpvc coupling on a water main?


Mike 3 years ago

Is it okay to use the dresser coupling on galvanized pipe installed in a concrete floor. It is in our bathroom.

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