If you have backflow repair that needs to be performed, there are a number of systems that can be used to prevent further backflow issues. Below is a list of various types of backflow valves and their qualities.
Air Gap • Maintains a physical separation between potable water and non potable water systems • The gap must be maintained at all times and must be a minimum of two times the diameter of the supply pipe
Atmospheric Vacuum Breaker (AVB) • Designed to prevent back-siphonage but will not protect against backpressure • One must be installed for each irrigation zone directly after the control valve • No valves can be installed downstream of the AVB • Must be installed at least 6”above the highest point of water in the zone it serves
Pressure Vacuum Breaker Assembly (PVB) • Effective against back-siphonage but not against back pressure. • Must be installed a minimum of 12 inches above the highest point of water they serve • There can be no pumps or backpressure on the downstream side • Should not be used in a system that introduces chemicals and fertilizers
Double Check Valve Assembly (DCA) • Protects against both backpressure and back-siphonage • Control valves can be located downstream • Should not be used in a system that introduces chemicals and fertilizers
Reduced Pressure Backflow Assembly (RPBA) • Protects against backpressure and back-siphonage • Only one RPBA is required to serve the whole system • Is installed upstream of all control valves • Must be installed a minimum of 12 inches above ground level
No matter what type of backflow prevention assembly you use, it should have a backflow test performed on a regular basis. Having a backflow prevention test performed regularly helps ensure that the device is working properly