Hendrickson Bros Hose Thread Backflow Preventer
Backflow prevention devices are recommended with any irrigation system with a shared water source. The Hendrickson DG41 Backflow Preventer (Atmospheric Vacuum Breaker) is an economical choice to prevent the risk of backflow contamination from outdoor hose faucet connected devices. The DG41 is made of high strength ABS plastic for reliability and durability. When using with an automatic water timer place backflow device on outlet of the timer.
Special Notes:
During normal operation the backflow preventer will appear to "leak" after the system or timer is turned off. This is normal as the backflow preventer is allowing water to drain from the system without entering the water supply. The amount of water drained will be equal to or less than the water capacity of the drip system. For optimal operation the backflow preventer should be installed higher than the emitters.
This fitting is not designed to be operated under constant pressure. It must be placed after any timers or valves in your system.
Garden Hose Threads (GHT, FHT, MHT) are unique in that they make the water-tight seal with a flexible washer between the two connection pieces. Thread seal tape is not recommended since it can inhibit the full threading together of the pieces, thus not allowing a tight leak-proof seal. GHT are not compatible with NPT or IPT/IPS fittings commonly found in iron pipe or PVC water systems.
