Draining the backflow preventer is necessary to prevent damage of broken pipes and parts.
- Turn off your water supply valve for the sprinkler system at the Main Shut Off Valve A. This is generally in the mechanical room of your home. A 3/4″ copper pipe tees off for the sprinkler system on the up-leg of the main water line after the meter, but before it goes into the hot water heater.
- Open all inlet and outlet drain valves on the backflow preventer. B and E
- Turn inlet and outlet ball valve handles to a 45 degree angel position. C and D
- Open drain valve near water supply valve to drain water back from backflow preventer.
- Some systems have manual drains in valve boxes outside that also need to be opened to help gravity drain the system. Other systems are equipped with automatic drain valves.