Subsurface Drip Irrigation Guide - Page 10
Line Flushing Valves
Line Flushing Valves eliminate the need for periodic manual flushing. They are not required on a zone of Techline CV dripperline because of Techline CV's unique check valve feature, but they do work well with Techline as a means of flushing the lines automatically.
These "automatic" flush valves release approximately one gallon of water each time the zone is turned on. Observe the flushing operation at each line flushing valve at the beginning of each irrigation season to ensure that flushing is occurring properly.
If the line flushing valve does not seal, (continues to flush) disassemble the flush valve. Inspect all components, cleaning or replacing all components, and reassemble. You should be able to blow and draw air through the dripper that is attached to the diaphragm, and the diaphragm should be free of any rips or tears.
Damage may occur if the flush valve has been subjected to higher than recommended pressure (greater than 57 psi).
If manual flush valves or flush ports have been installed in lieu of line flushing valves, they should be opened and the system flushed at least three times each irrigation season until the flowing water is visibly clean. The zone may need to be flushed more frequently depending on the water source.
Flushing is also recommended anytime that the system has been repaired.
Figure 37 - Diaphram in operation
Figure 38 - View of Line Flushing Valve Mounted on an Exhaust Header and Cut-Away View During Operation
System Inspection
Line Flushing Valves eliminate the need for periodic manual flushing. They are not required on a zone of Techline CV dripperline because of Techline CV's unique check valve feature, but they do work well with Techline as a means of flushing the lines automatically.
- Observation of the flushing operation of all line flushing valves. Check the pressure at the flush valves and compare to the last maintenance inspection. The minimum pressure should be at least 10 psi, (20 psi with Techline CV) and the maximum pressure should not exceed 57 psi.
- Inspection of the zone while it is operating, looking for excessively wet or dry areas that might indicate leaks. If a leak is found, and the system is installed as a grid or closed loop system, water will flow from both sides of the break. With the zone still on, allow the running water to flush any debris clear, and repair the leak with the appropriate fitting.
- Check the operational flow of each zone to see if it coincides with the designed or initial flow of the zone. Higher flow could indicate a leak. Locate any wet areas and repair. Lower than expected flows could indicate clogged drippers or kinked dripperline tubing.
A historical record of the system should be kept. Recorded data should include:
- Type of dripperline installed (dripper flow and spacing)
- Lateral spacing
- Depth of the dripperline
- Initial zone flows and pressures
- Initial pressures at the flush points
Winterizing a Netafim System
Winterizing your Netafim system is fast and easy when you follow these simple steps. In general, the polyethylene tubing found on most drip and dripperline systems has the ability to expand and contract. Winterizing your system is necessary to protect the hard plastic and metal components that are normally present.
Winterizing Techline
Drippers in these products will drain some water from the dripperline each time the zone shuts off, but there are still a few important steps to follow.
Winterizing Techline
Winterizing Techline CV
Techline CV dripperline has a check valve in each dripper. These check valves hold water inside the dripperline, so care should be taken to ensure water is adequately drained from the zone.
Winterizing Techline CV
Conclusion
It has been our goal to explain the concept of subsurface dripperline using Techline CV and Techline in a simple, informative way. Subsurface dripperline is an irrigation technology that contractors around the world have been using for years with excellent success. We hope that you agree that because much is known about it, using it is both a logical and safe decision.
For specific product and design recommendations, we encourage you to review the following materials:
- Netafim USA Landscape & Turf Division Catalogue
- Techline CV Design Guide
- Techline Design Guide
- Netafim USA web site at www.netafim-usa-landscape.com
Each of these will provide you with even more specifics regarding the proper choice and application of products. They are available at your local Netafim Landscape & Turf Distributor or on-line at www.netafim-usa-landscape.com.