Watts 957Z - Manual (Page 2)

2
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
and #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. (Figure A)
2. Insert a #3 screwdriver through the hole on the top of the
cover sleeve and using both hands rotate the cover sleeve
approximately 1 ⁄
4
-turn clockwise and 1 ⁄
4
-turn counter-clock-
wise to break the sleeve O-ring seals. Using the screwdriver,
slowly slide the cover sleeve to the downstream side of the
housing. (Figure B)
3. Remove the stainless steel check retainer from the housing.
(Figure B)
4. Remove the #1 check module (Figure C) by inserting two flat
blade screwdrivers into the slots on either side of the check
module and gently pry the check module toward the open
zone.
5. Remove #2 check module with the same instructions as in #4
above. For servicing 6" (150mm) checks see 8" – 10" (200 –
250mm) instructions on p. 4.
6. To clean or inspect either check module, insert a #3 screw-
driver through the downstream side of the check module as
shown in Figure D and E. When the screwdriver is in place,
remove the E-clip (Figure F) and pin connecting the structural
members and the check clapper will open with no tension.
7. Thoroughly clean the seating area. The sealing disc may be
removed, if necessary, by removing the screws connect-
ing the keeper plate to the clapper. The sealing disc may be
reversed and reinstalled if the elastomer is cut or damaged.
8. Wash check module and O-ring and inspect for any damage.
If damaged, reinstall new parts.
9. After thorough cleaning, lubricate O-ring w/FDA approved lu-
bricant, replace pin and E-clip in structural members, remove
screw driver and reinstall check modules and assemble hous-
ing in reverse order of these instructions.
Maintenance
Instructions
Series 957, 957RPDA,
LF957RPDA
2 1 ⁄
2
" – 6" (65 – 150mm)
Relief Valve Discharge Rates 2 1 ⁄
2
" – 10" (65 - 250mm)
957, 957RPDA and LF957RPDA
lpm gpm
1330 350
1140 300
950 250
760 200
570 150
380 100
190 50
0 0
0 20 40 60 80 psi
0 138 276 413 551 kPa
Rate of Flow
Pressure
Horizontal Installation
N Pattern
Z Pattern
Figure A Figure B Figure C
Figure D Figure E Figure F
#2 Check Diagrams
Figure D Figure E Figure F
#1 Check Diagrams
Installation Instructions
Series 957, 957RPDA, LF957RPDA