Watts 774DCDA - Manual

For Non-Health Hazard Applications
ES-774DCDA
Job Name ––––––––––––––––––––––––––––––––––––––––––– Contractor ––––––––––––––––––––––––––––––––––––––––––––
Job Location ––––––––––––––––––––––––––––––––––––––––– Approval –––––––––––––––––––––––––––––––––––––––––––––
Engineer ––––––––––––––––––––––––––––––––––––––––––––– Contractor’s P.O. No. –––––––––––––––––––––––––––––––––––
Approval ––––––––––––––––––––––––––––––––––––––––––––– Representative ––––––––––––––––––––––––––––––––––––––––
IMPORTANT: INQUIRE WITH GOVERNING AUTHORITIES
FOR LOCAL INSTALLATION REQUIREMENTS
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 sys-
tems when connected to a potable water supply. Degree of hazard present 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 thermo-
plastic construction with stainless steel hinge pins, cam arm and cam bear-
ing. 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 assembly. 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 assem-
bly 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
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.