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.

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.

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.

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.

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