Sunday, March 15, 2009

The Sprinkler System Project: Repairing PVC Pipe

These photos show three of the types of repairs I made on the pvc pipe in our sprinkler system. In the system that Jack Dewhurst had installed about five years ago and which had been damaged by the workmen who did our renovation, I had to locate and repair a total of eight breaks or simply missing sections in the underground piping.

I located the breaks by starting at the well head. At the well head, there is a valve that divides the water into three zones. I would select a zone, turn on the pump, and then walk along what I knew to be generally the underground path of the pipe until I came to the first break. I knew when I found one, because the ground would be wet at the break or, sometimes, there would be water simply gushing up from the ground into the air, like Old Faithful. I would turn off the pump, and start digging. When I finished that repair, I turned on the pump again and walked the zone further to see where the next break would be, if any, or whether, instead, the sprinklers would all spring into action.

As you can see in the photos, when I found a break I would dig a trench that exposed the pipe section in question. Then I would take a hack saw and cut the damaged portion out or round off the ends of the pipe in place if a section were simply missing.

PVC pipe is easy to work with, as long as it is in an unconfined place. Our system uses 1 1/4 inch pipe, which is no problem at all to handle. Lowe's and Home Depot have the pvc pipe in all sizes and all the common fittings. The pieces glue together easily and quickly with a liquid primer and an adhesive made especially for this work. I have a Black and Decker WorkMate and it provides the portable workbench/holding platform to cut the pipe. (I probably have the first version on the WorkMate, a marvelous invention that Carol gave me 25+ years ago.)

The problem with making these repairs is that the pipe is definitely not in an unconfined place. The first photo indicates the problem.

The basic repair involves cutting out the damaged piece of pipe; cutting the appropriate length of new pipe from replacement stock; priming/gluing a new coupling to each end of the sound pieces; and then fitting the repair piece into place at the exposed ends of the system pipe, one end at a time, after priming/gluing each end of the exposed pipe under repair.

The problem is that the pipe under repair is set in the ground and, like the replacement piece, has very limited flex. There is also very little lateral movement of the pipe in the ground.

The first photo shows the solution in a particular case. I dug the trench up to a nearby elbow and then dug a second trench that followed the 90 degree turn. At the 90 degree turn, I widened the trench so that I could push the pipe section under repair in the direction of the elbow, giving me enough room between each of the pipe ends under repair to slip in my new piece.

The second photo illustrates two problems. Here I did not have a nearby elbow to help me make room for a replacement section. In addition, one section under repair was a break in a 30 long section of pipe that Jack, upon initial installation, had gently flexed to follow the boarder of the front driveway. The plumber who installed the drain line from the new bathroom simply had to remove about a two foot section of that pipe. There was not nearly enough room for the sort of flex one could safely coax from a repair section of pvc. Furthermore, the angle between the exposed ends of the pipe under repair was less than 22 degrees. I could not find an elbow that would help me fit in the replacement section, and the pipe, as usual, had very little horizontal (longitudinal) play, if any at all.

Enter Flexible PVC. I learned about this miracle solution on the internet. I went back to Home Depot and Lowe's which carried flexible pvc, but neither of them had it in the 1 1/4" variety. But a supply house in Nevada had it, and within a week of my order I had a five foot piece in hand. It made an easy fit, as the photo indicates.

At the bottom of the photo you can also see a "T" junction which was completely broken when I dug out this section. Here I had very little room to maneuver, but a fitting called an expansion repair coupling came to the rescue. This coupling has a telescoping feature that will shorten and lengthen the coupling over about 5 inches of play. To install it, you remove about a foot or so of the pipe with the break; then separate the coupling into its two pieces, gluing one piece to each of the ends under repair; and then slide the coupling closed and tighten it. The coupling has a rubber bushing that seals it in water-tight fashion. Amazing. I used several of these.

There are some other repair approaches. For example, if there is simply a small hole, there is a sort of pvc patch that one can paint with the glue and snap around the section of pipe that has the hole. None of the breaks I had were that small. And there is also a compression fitting available, but I couldn't figure out how that was to be used.

As much as the Lowe's and Home Depot people advertise about having experts at hand to help you, I found myself to be pretty much on my own at those places. One bit of irony is that on my very last visit to Lowe's, I came across an instructional CD entitled Sprinkler System Design and Installation. It was very inexpensive and I bought it, but I'm not sure I want to see it. (I shouldn't say I was on my own. Carol often went with me on my shopping expeditions. She became quite knowledgeable after several visits, and she had the patience to sort through the various boxes at Lowe's and Home Depot that often were either wrongly labled or had the wrong parts mixed up in them.) (Rain Bird has an instructional video on sale at its website.)

The other renovation job I asked our contractor to come back and fix is the driveway itself. We have an old fashioned asphalt, circular drive. What we would like to have are "pavers," that is, a driveway of bricks that are laid cobblestone fashion and can look very nice. The contractor is nowhere in sight.

Let me see, what should I do . . . ? Now that would be a project!


Macon said...

Looks great, Padre!

Paul Stokes said...

Thanks, Macon!