Repairing a Straight Line Break in Your Irrigation System - Web Exclusive!

2/27/2012

Repairing a
Straight Line
Break in Your
Irrigation System


by Katie Navarra

        Irrigation systems allow farms to control the timing and amount of water applied to a multitude of crops. Depending on the crop grown, the system can be installed on the soil's surface, underground or in a greenhouse suspended above the crop. All three types of systems can be susceptible to a break or puncture in the mainline pipe that delivers water from the source to the first section controlled by a zone valve. Fortunately, the repair is typically one that can be done without the help of a professional repair company.

        First, locate the leak. Trace the flowing water back to its source. Small punctures can be more difficult to find, but are indicated by poor system performance or bubbling of dirt/grass around the break if the pipe is underground.



To avoid purchasing the incorrect fitting take a small piece of the broken pipe
to the store. The dripper line pictured here takes specific fittings and even
though the coupling pictured appears to fit it is actually to large for the pipe and
will come off the pipe once the system is pressurized with water.



        Next, determine the type of pipe that needs repair. Is the pipe schedule 40 PVC or schedule 80 PVC? Is it polyethylene or low-volume dripper line? The type of pipe will determine the materials needed for the repair. Knowing the inside diameter of the pipe is also important in order to purchase the correct size replacement fittings.

PVC Pipe
        Dig out 5 to 6 inches around all sides of the broken pipe. If the break in the pipe is submerged in water, bail out the water and dry the pipe. Primer and glue are used to bond PVC pipe and repair fittings. PVC pipe glue is made in a variety of formulations. Purchase the type of glue that best matches the temperature and air moisture the repair will be made in. The pipe must be dry for primer and glue to seal properly. A clean work area also limits the debris that can fall into the pipe and cause plugged pipe junctions.

        Repairing a straight section of PVC pipe can most easily be accomplished with a telescoping repair coupling. A telescoping repair coupling is adjustable in length allowing for greater flexibility. Measure the inside diameter of the pipe to determine the correct size replacement fitting needed.



A coupling, like the one pictured here, can be slid into to open ends of poly pipe
to make a quick repair on a straight section of pipe.



        Hold the repair coupling next to the damaged section of pipe and measure the length of pipe that needs to be removed. Cut out the damaged section. Clean the pipe with a rag to remove any dirt and moisture. Check the dry fit before applying glue. The pipe should slide at least one-third of the way into the repair fitting without added force.

        Glue one end of the telescoping coupler onto the pipe, pull out the other end to the desired length and glue to the pipe. Telescoping repair couplings are available from .25 up to 6 inches in diameter. Work quickly, but be careful not to over apply the glue and brush off any excess. Allow the glue to set before testing the repair or backfilling around it.

        Joints on PVC pipe over 2.5 inches require a few extra steps and potentially even thrust blocking behind the fittings. Water hammer on larger-sized pipe can exert excess pressure on the fittings and pipe, causing them to rupture or blow up under the pressure. If you are repairing pipe over 2.5 inches, consider calling a professional.

A video demonstration




Drip line tubing and poly pipe

        Repairing a straight line break in drip irrigation systems is simple, but knowing the size of the pipe is critical. The inside diameter of drip line pipe varies among manufacturers and even a 1 millimeter difference in diameter matters.

        Cut off a small section of the pipe and take it to the store to purchase the proper size coupling. A coupling is a small, cylindrical-shaped tube made of hard plastic that will slide into the open ends of drip tube to make a complete connection. Repairing a straight line section of dripper line is a quick fix. Hold the coupling next to the damaged section of pipe to determine the length to cut out. Remove the damaged section and insert the coupling into both ends of pipe. The video link below shows the contractor using clamps on either side of the coupling, but they are not necessary in low volume systems. http://www.thisoldhouse.com/toh/video/0,,20057723,00.html

        Repairing a straight line break in poly pipe is similar to repairing a break in PVC and dripper line pipe. Knowing the diameter of the pipe is key to purchasing the proper repair fitting. Poly pipe can be repaired with a telescoping coupling like the one described in a PVC repair or a straight "barb" coupling similar to the one for dripper line repairs can be used.


A coupling, the small gray section between both ends of the pipe,

allows for a quick repair for breaks in poly pipe.



        Poly pipe does not require the use of glue or primer. However, clamps do need to be used on both sides of the fitting to ensure that the slice remains connected.

        Katie Navarra is a freelance contributor based in Clifton Park, N.Y., and writes about agriculture and the equine industry regularly. All Photos by Katie Navarra.





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