Watts 994 Serie Manual De Instalación & Mantenimiento página 4

Servicing First and Second Checks
4" – 6"
Before servicing, be certain the shutoff valves are closed. Then use
the following procedure to remove the check assemblies.
1. Slowly open all ball valves to relieve air and water pressure.
Loosen the bolts on the groove coupler and remove the groove
coupling and cover plate from the valve body. (See Figure 1.)
2. Remove check assembly #1 by hand, turning the screws counter-
clockwise to release the check and remove it through the top access
port. Do not use the check arm as a handle to unscrew the unit. If
the check cannot be loosened by hand, insert a long screwdriver
between the valve body and the check. (See Figure 2). Gently apply
pressure against the check until it is loosened. Finish unscrewing by
hand. (See Figure 3.) Unscrew check #2 by turning counterclockwise,
placing a long screwdriver across the lugs and applying pressure to
loosen the check. (See Figure 4.) Fin ish un screw ing by hand.
3. (For 6" only) To clean check #1, locate the check arm opening
stud on the outlet flange of the valve assembly. Slide the check
arm over the stud with the check threads facing downward. (See
Figure 5A.) Tighten the 1/4" nut on the stud to secure the cam bar.
Figure 1
Figure 3
Check #1 2
O-ring Seal &
Groove
Seat
Figure 5A
4
1 ⁄ " – 6"
2
Spring
Cam Arm
Roller
Clapper
Cam Bar Open Pin
Valve Outlet Flange Threaded
Stud on Flange
6"
Check #2 RP
Slowly pull the assembly outward to open the check, allowing
exposure of the seat clapper area for cleaning.
To clean check #2, lift the cam arm and hold it in the open
position. (See Figure 4.) Raise the clapper so that the end of the
check arm rests between the roller and the clapper. (See Figure
5B.) Thoroughly clean the seat area and clapper sealing surfaces
of both checks. Inspect seats, clapper sealing surfaces, check
arms, and O-rings for damage, nicks, and debris. If not damaged,
gently close the clapper. If damaged, install a new check assembly
or O-ring, or both.
4. Before reinstalling the checks, thoroughly clean the O-ring groove
and lubricate the O-ring with an FDA Approved lubricant. Insert
and thread check #2 first and then check #1. Check #2 should
be tightened by inserting a long screwdriver between the lugs to
tighten firmly. (See Figure 2.) Do not overtighten. Tighten check #1
firmly by hand only. Replace the cover plate, clean groove coupler
gasket, and groove. Replace the groove coupler. Repressurize and
bleed air from all the test cocks.
Figure 2
Check #1
Figure 4
Check #2
O-ring Seal & Groove
Lug
Seat
Figure 5B
A
B
Screwdriver
Check #2
C
Spring
Cam Arm
Roller
6" Only
Clapper
O-ring Seal & Groove
Cleaning Position