Clogged drain could be fixed with adapter

Q. We moved into our 1999 home just over a year ago and have already had problems with our basement washing machine clogging and spilling water onto the floor from the point where the machine’s drain hose empties into the wall drain.

Roto-Rooter told us that lint clogs the pipe where the water drains from the machine and nothing can be done other than to have them come out to clear the clog. Apparently this problem began before we moved here. Is there anything we can do to prevent the lint from clogging the drain pipe? – Candace A., Spokane

A. I’m surprised that lint could clog a 2-inch ABS drainpipe. Since it took about a year for the clog to build up, indications are that a nail or some type of construction material may have fallen into the standpipe during construction and landed in the P-trap. It most likely is not lodged in the P-trap because the snake gets past it but it may be resting at the bottom where it could catch lint. The obvious approach is to check inside the P-trap by removing it (if it’s removable) or cutting it off (if it’s not). If the pipes are concealed in a finished wall, the wall will have to be opened up for this procedure.

However, thanks to your photos, I spot a copper pipe (not sure if it’s rigid or soft) coming out of the far side of the standpipe about an inch or so above the P-trap. It appears that there is caulk around the copper pipe where it enters the ABS pipe. I also see that the basement is unfinished and the pipes are exposed, which will make the project easier.

This tells me two things. First, the copper pipe acts as a trap primer by feeding water to the P-trap in a nearby floor drain. Also, an improper fitting was used to attach the copper pipe to the standpipe. Most likely the copper pipe protrudes into the standpipe where it catches lint yet the snake can still get past it.

Because the Uniform Plumbing Code (UPC) requires that all floor drains be primed, water must be supplied to the P-trap to keep the trap filled with water. If the trap goes dry, then sewer gases could enter the home. One way to prime a floor drain is to use an actual trap primer valve ( http://www.pppinc.net/p1p2.htm), which would tap a nearby cold water line for its water supply. The second method, as shown in your photo, is to tap into the washing machine standpipe. Every time the washer discharges water, the water swirls around inside the standpipe and the primer outlet captures some of it for the floor drain’s P-trap.

Another solution could be that an ABS tapped P-trap adapter could solve the problem. Known as a “PPA” (Precision Priming Adapter), it is manufactured by Precision Plumbing Products, Inc. ( www.pppinc.net/ba.htm). It’s also known generically as a “BAP” adapter after the name of its first manufacturer.

If the PPA adapter is not available at local home centers, you can purchase it off the Internet or from a contractor’s plumbing supply house.

The PPA adapter has a brass compression fitting on one side to accept the copper primer line. The entire unit then fastens to the inside of an ABS fitting or coupling with solvent cement.

To install a PPA adapter, begin by using a copper tubing cutter to cut the primer line in a straight area of the tubing. A coupling will be used later to reconnect the primer line to the drainpipe. Remove the remaining copper tubing from the standpipe. Then disconnect the washer box by removing the screws and any clamps around the water supply lines that run into the box. Next cut the standpipe using a 15-pt. Japanese handsaw just below the point where the primer line entered the drainpipe, which should leave enough drainpipe so you can later apply solvent cement, a coupling, and finally the adapter.

Be sure to take into account the overall height of the installed PPA adapter so you can accurately cut the end of the drainpipe that will glue into it.

When you are satisfied with the overall finished height of the washer box and placement of the adapter (a dry fit), use a white or yellow marker to draw alignment marks to show the final positions of the coupling, adapter, and standpipe. Then disassemble everything and dry all component pieces.

You are now ready for assembly. Apply a thin, even coat of ABS solvent cement to the inside of the coupling. Slide the coupling over the standpipe stub, using enough force to ensure that the stub bottoms into the coupling before the cement evaporates. As you do this, turn the coupling a quarter turn to evenly distribute the solvent cement and to align your marks. Apply solvent cement to the inside of the coupling and seat the adapter in the coupling, again making a quarter turn and ensuring that you line up your marks.

The last connection may prove awkward because the water lines attached to the washer box will make it difficult (or impossible) to twist the standpipe to its alignment marks. Apply solvent cement, a little more than usual, to the inside of the top of the adapter and insert the bottom of the top portion of the standpipe, aligning the marks. At this time, refasten the washer box and any water supply clamps.

Temporarily screw the compression fitting into the threads on the side of the PPA adapter using an adjustable wrench. Do not over tighten. Then remove the compression ring and nut on the end of the compression fitting.

Now it’s time to reattach the copper pipe cut off earlier. Instead of using the old piece, cut a new piece of soft copper tubing so it will run from inside the compression fitting to the end of the primer line, allowing space for the copper coupling.

Now remove the compression fitting to provide air space between the end of the copper and the ABS pipe (you don’t want to damage the PPA adaptor from the copper tubing that may get hot when sweating the coupling). Clean both the inside of the coupling and the outside ends of both copper pipes using a 4-in-1 cleaning tool. Apply flux to the inside of the coupling, slide the coupling onto one end of the primer line, and then slide the other end of the copper tubing into the coupling. Before soldering, align the soft copper tubing with the site of the PPA adapter’s compression fitting. You may have to secure the pipe so it doesn’t move.

Use a portable hand-held torch to apply heat to the center of the coupling, which will heat both ends of the coupling at one time. Once the ends are hot, pull the flame away from the fitting and touch solder to one joint. The flux will help draw the solder up into and around the joint. Quickly repeat the soldering process for the second joint.

When the copper tubing has cooled, apply Teflon tape clockwise to the threaded end of the compression fitting and screw it into the threaded area on the side of the PPA adapter. Slide the compression nut onto the copper tubing so the threads point outward, slide on the compression ring, fit the copper tubing into the compression fitting, slide the compression ring and nut forward, and thread the nut onto the threads on the end of the compression fitting. Tighten by hand and then use two open-end wrenches, taking care not to over tighten.

This project will take a little time but overall it will cost less than calling in plumbers for yet another service call. Best of all, it will solve the problem.