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Irrigation System Installation

Proper installation of the irrigation system is required for efficient irrigation and water conservation. The following are general guidelines for irrigation system installation.

  • Call utility companies (telephone, cable TV, electric, gas, and water) for blue stake service to mark all utilities in the construction area before digging or trenching.
  • Use drawings and specifications to mark locations of valve boxes, pipe, sprinklers and drip emitters before installation. Mark locations with flags or stakes. This visual inspection of the system allows for minor adjustment in the system layout before installation.
  • If the irrigation system is being installed in phases, plan ahead so the landscape does not need to be disturbed for installation of pipe and wire required later.
  • Installed pipe should be deep enough so that ground frost, soil aeration and tillage operations can’t disturb the pipe. For medium to large irrigation projects, a mechanical trenching machine may be rented to reduce labor. The pipe and wire should be bedded in soil without large rocks. Most pipe used in irrigation systems is PVC which requires both threaded and glued connections. Two layers of teflon tape should be used on the male end of PVC threaded connections. Excess teflon tape and over tightening threaded connections can cause excessive stress on joints. One turn past hand tight in general is sufficient. Flush the pipe line before installing sprinklers.
  • Wire conections must be make between each valve solenoid and the irrigation controller (time clock). Wire splices must be waterproofed. Wire nuts and plastic tape are not waterproofing. Waterproof wire connection kits can be purchased. Make all wire splices in valve boxes.
  • Use white wire as the common and colored wires for “hot” wires. Valves should be installed in valve boxes which allow access to the valves for repair or replacement.
  • Rotating and spray sprinklers should be attached with appropriated size swing or flexible connections (figure 6). These types of connections provide protection to the pipe line and allow adjusting the height and level of the sprinkler. Install part circle sprinklers so that they are irrigating the proper area. Adjustment of operating sprinklers should be made immediately after installation of irrigation system.
  • Trenches should be back-filled and watered, then back-filled again. This reduces settlement of soil in the trench below the grade of the landscape.
  • During and after installation, drawings should be made with the true location of all irrigation lines (as-built plans) to assist in trouble-shooting, maintenance, repair and future modifications.
  • Drip irrigation systems are sometimes installed on the surface of the ground. When installing drip emitters in the tubing remember that the irrigation tubing is longer on a hot afternoon than in the cool mornings During installation of irrigation tubing allow enough slack in the tubing to account for temperature induced tubing length differences.

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