Specification Sheet
For Non-Health Hazard Applications
ES-774DCDA
774DCDAOSY
Now Available
WattsBox Insulated Enclosures.
For more information, send for literature ES-WB.
Series 774DCDA
Double Check Detector Assemblies
Sizes 2
1
⁄2" – 12" (65 – 300mm)
Series 774DCDA Double Check Detector Assemblies are designed for use in
accordance with water utility non-health hazard containment requirements. It
is mandatory to prevent the reverse flow of fire protection system substances,
i.e., glycerin wetting agents, stagnant water and water of non-potable quality
from being pumped or siphoned into the potable water supply.
Features
• Torsion spring check valve provides low head loss
• Short lay length is ideally suited for retrofit installations
• Stainless steel body is half the weight of competitive designs reducing
installation and shipping cost
• Stainless steel construction provides long term corrosion
protection and maximum strength
• Single top access cover with two-bolt grooved style coupling
for ease of maintenance
• Thermoplastic and stainless steel check valves for trouble-free
operation
• No special tools required for servicing
• Compact construction allows for smaller vaults and enclosures
• Furnished with
5
⁄8" x
3
⁄4" (16x19mm) bronze meter (gpm or cfm)
• Detects underground leaks and unauthorized water use
• May be installed horizontal or vertical “flow up” position
Specifications
A Double Check Detector Assembly shall be installed on fire protection
systems when connected to a potable water supply. Degree of hazard pres-
ent is determined by the local authority having jurisdiction. The assembly
shall consist of two positive seating check valves located between two
resilient seated shutoffs with a hydraulically balanced bypass line and four
test cocks. The main valve body shall be manufactured from 300 Series
stainless steel to provide corrosion resistance. The check valves shall be
of thermoplastic construction with stainless steel hinge pins, cam arm and
cam bearing. The check valves shall utilize a single torsion spring design
to minimize pressure drop through the assembly. The check valves shall
be modular and shall seal to the main valve body by the use of an O-ring.
There shall be no brass or bronze parts used within the check valve assem-
bly. The check valve seats shall be of molded thermoplastic construction.
The use of seat screws as a retention method is prohibited. All internal
parts shall be accessible through a single cover on the valve assembly. The
valve cover shall be held in place through the use of a single grooved style
two-bolt coupling. The bypass line shall be hydraulically sized to accurately
measure low flow. The bypass line shall consist of a meter, a small diameter
double check assembly with test cocks and isolation valves. The bypass line
double check valve shall have two independently operating modular poppet
check valves, and top mounted test cocks. The assembly shall be a Watts
Series 774DCDA.
Available Models
Suffix:
LF – without shutoff valves
OSY – UL/FM outside stem and yoke resilient seated gate valves
*OSY FxG – flanged inlet gate connection and grooved outlet gate con-
nection
*OSY GxF – grooved inlet gate connection and flanged outlet gate
connection
*OSY GxG – grooved inlet gate connection and grooved outlet gate
connection
CFM – cubic feet per minute meter
GPM – gallons per minute meter
Available with grooved NRS gate valves - consult factory*
Post indicator plate and operating nut available - consult factory*
*Consult factory for dimensions
Bypass Meter
Cover
Test Cock
Replaceable
Seat
Test Cock
Grooved Coupling
Bypass Double
Check Valve
Test Cock
Resilient
Disc
Laser Cut Polished Cam Arm
Job Name
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Contractor
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Job Location
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Approval
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Engineer
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Contractor’s P.O. No.
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Approval
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Representative
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Watts product specifications in U.S. customary units and metric are approximate and are provided for reference only. For precise measurements,
please contact Watts Technical Service. Watts reserves the right to change or modify product design, construction, specifications, or materials with-
out prior notice and without incurring any obligation to make such changes and modifications on Watts products previously or subsequently sold.
NOTICE
Inquire with governing authorities for local installation requirements