Watts 3/8-SD3-LS-MF-MF, 3/8" Flare Dual Check Backflow Preventer

Watts Series 3/8 SD3-MF, SD3-LS-MFxMF is a dual check valve backflow preventer with atmospheric port designed for carbonated beverage machines preventing the reverse flow of polluted water, such as carbon dioxide gas and carbonated water, from entering into the potable water supply due to back pressure backflow. These substances can flow from post-mix beverage systems and are very acidic. If the acidic water comes in contact with copper tubing or copper pipe, it will cause the leaching of copper salts into the water supply. The dissolved copper if ingested can cause nausea, abdominal pain, and in some cases vomiting.
The Watts Series 3/8 SD3-MF, SD3-LS-MFxMF consists of stainless steel body construction with internal rubber components and is designed for continuous or intermittent pressure applications. It has an atmospheric port that provides visual indication of failure of the second check. It is ideal for use on post-mix carbonated beverage equipment and dispensing equipment for tea and coffee. It has SAE male flare end connections. Maximum working pressure is 150 psi (10 bar).
Watts Series 3/8 SD3-MF, SD3-LS-MFxMF is recommended for use on Post-Mix Carbonated Beverage Equipment and equipment for tea and coffee.

Installation Instruction
Before installing, flush out pipe lines to remove scale and other foreign matter. The valve can be installed horizontally or vertically (flow up or down). Install the valve in the line with the arrow on the valve body pointing in the direction of flow. Connect a vent discharge line to the vent outlet of the Watts Series 3/8 SD3-MF, SD3-LS-MFxMF and vent to a safe place of disposal with adequate ventilation. The valve should be installed such that the strainer and the valve are accessible for service and maintenance.
THESE WATTS DOUBLE CHECK VALVES VENT ATMOSPHERICALLY, MEANING WATER WILL LEAK FROM THE VENT PORT!
Some may leak more than others depending on the installation source. Installers must use a Fitting and Tubing of your choice to run to a floor drain or drain saddle, see related items below.
This will satisfy the bureaucrat that is stopping you from making coffee & beverages.
Please read and follow the installation instructions SD3 Specification Sheet and Installation Instructions