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ES1595 REV A.
BFMMDC4S00
The Double Check Valve (DCV) device consists of two independently acting, spring loaded check valves. Two resilient seated shut-off valves
and four test cocks complete the assembly.
Each check is designed to maintain a minimum of 1 psi across the valve during normal operation. If at any time the pressure downstream of
the device increases above the supply pressure, both check valves will close to prevent any backflow from occurring.
The various styles and sizes of Double Check Valves are illustrated in figures 1, 2, 3, 4 and 5.
I.
DESCRIPTION AND OPERATION
II. INSTALLATION
1. The DCV must be installed in an accessible location to facilitate periodic field testing and maintenance.
2. Flush all upstream piping thoroughly to remove foreign matter prior to installing the device.
3. The device should be installed horizontally for ease of maintenance and testing. A clearance between the lower most portion of the device and
flood grade or floor should be provided for ease of maintenance.
4. When shut-off valves are provided separately, they should be installed with a test cock on the upstream side of the inlet shut-off valve.
5. After installing the assembly and with downstream or #2 shut-off valve closed, pressurize the device and bleed air through test cock #4. Then
open #2 shut-off valve.
FIGURE 2
40 - 10X-A2
Y - PATTERN
NO FLOW CONDITION
FIGURE 2
1/2” - 4S-103
NO FLOW CONDITION
FIGURE 1
1/2” - 40-103
