Atmospheric Vacuum Breakers: Installation
Atmospheric vacuum breakers can be installed along with irrigation zone pipe. The irrigation site plan will indicate locations. They must be installed one on each zone downstream from the automatic zone control valves in an inconspicuous location protected from lawn equipment but accessible for maintenance. Atmospheric vacuum breakers must be installed a minimum of six inches above the highest outlet on the zone. Some local codes require twelve inches. Zone pipe may be copper, PVC, or Poly. Purchase the correct adapters for the type of pipe. Install the valve so that the inlet is positioned at the bottom, the bonnet at the top, and the outlet is centered at or above the minimum height requirement.
Automatic Anti-siphon Zone Control Valves: Installation
Installation of anti-siphon automatic zone control valves is similar to underground installation with a few notable differences. Valves must be at least six inches higher than the highest outlet on the zone. The irrigation site plan will indicate the location of manifolds. Use a laser or string level find minimum height at the installation site. The manifold is installed in an open trench instead of a valve box.
Both the inlet and outlet on an anti-siphon automatic zone control valve are on the bottom of the valve. Find an arrow on the valve body that indicates direction of flow. The manifold is built exactly as for underground installation except that the length of pipe between each tee and corresponding valve inlet is the distance between the bottom of the trench and the required valve height. Allow room between valves for maintenance. Then the entire manifold is connected to the supply line with the tees' center outlets vertical and the valves above ground.
Backfill carefully but firmly after testing the manifold and connecting lateral lines.
As with all above-ground valves, a protective cover must be provided. Most jurisdictions allow a removable cover. If the cover is stationary, it must be roomy enough and the access door must be large enough to access all the valves with necessary tools for maintenance and repair.
Atmospheric Vacuum Breakers: Maintenance, Repair, and Replacement
Repair is necessary when the atmospheric vacuum breaker continuously or too frequently discharges water. In most cases, foreign material is preventing the check from seating firmly against the air gap. Remove the bonnet and check assembly. Rinse each part with clean water and inspect for damage. If no damage is found, reassemble and test. If necessary, obtain an atmospheric vacuum breaker repair kit consisting of all new internal parts. SprinklerWarehouse.com has these in all major brands ready to ship. Before replacing an atmospheric vacuum breaker, make sure local code still allows new installations of this type of backflow prevention device.
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