Watts 757N - Manual (Page 3)

3
Material/Tool Requirements:
• #3 Phillips screwdriver or 5 /
16
" diameter rod, length sufficient
to span diameter of check, see Figures A and B.
• 1 /
2
" – 13 x 5" fully threaded hex bolt (Service bolt).
• 3 /
4
" open end or socket wrench.
Instructions:
WARNING !
Prior to servicing any Watts valve, it is mandatory to shut
down the water system by closing both the inlet and outlet
shutoff valves. After shutoff valves are closed, open test
cock #2, #3 & #4 to relieve pressure within the backflow
assembly.
1. After #3 test cock has been opened to
relieve pressure, remove #3 test cock from housing. When
repairing an 8" or 10" (200 – 250mm) device, remove both
Victaulic couplers from body. Slide the downstream Victaulic
coupler gasket to the downstream side of the housing. The
upstream Victaulic coupler gasket stays in place.
2. Remove check/s to be serviced.
3. Locate the service hole and thread in the service bolt by hand
until it contacts the linkage. (Figure A)
4. Continue to thread in service bolt with the wrench until the
service hole in the linkage is aligned with the service notches
on the spring arbors. (Figure A)
5. Insert the Phillips screwdriver through the arbors and service
hole of the linkage making sure that the tip of the screwdriver
extends past the ends of the arbors by a minimum of 1 /
4
"
(6mm). (Figure B)
6. Back out the service bolt until load is transferred to the screw-
driver. Continue to back out the service bolt until sufficient
clearance is achieved to remove the complete spring mecha-
nism.
7. To disconnect linkage, remove retaining clip and pin (store in
a safe location for reinstallation).
8. To remove spring mechanism, grasp the screwdriver at the
center and pull complete assembly straight out and store in
a safe place.
9. Reinstall in reverse order.
WARNING !
While the spring mechanism is removed for check servicing;
never pull the screwdriver out or off the support notches on the
arbors. Doing so may cause bodily injuries.
Maintenance Instructions
Series 757, 757DCDA & LF757DCDA
8" – 10" (200 – 250mm)
Figure A
Figure B
Service Hole
Sleeve O-ring
and Gasket
Check Module
O-ring
First Check Module
Closure Sleeve Test Cock
with O-ring
Closure Sleeve
E-clip
Disc Elastomer
Second Check Module
For repair kits and parts, refer to Backflow
Prevention Products Repair Kits & Service Parts
price list PL-RP-BPD on www.watts.com