Installation Guide

ZURN WILKINS
1747 Commerce Way, Paso Robles, CA 93446 Phone:[phone] Fax:[phone]
#1 CHECK ASSEMBLY
#2 CHECK ASSEMBLY
Maintenance Instructions
3
SERVICING CHECK VALVES
A ratchet wrench, 11/16” deep socket, and a 4” long extension
are recommended for removing check assemblies.
1. Close inlet and outlet shut-off valves.
2. Open No. 2, No. 3 and No. 4 test cocks to release pressure
from valve.
3. Loosen & remove the grooved coupling around the access
cover. Remove cover.
4. To service only the #1 check assembly, remove the 6 bolts,
washers and o-rings from the back of the #1 check assem-
bly. Separate the retainer and the seal ring from the check
assembly and proceed to step #8.
5. To service both checks or the #2 check, the #1 check
assembly must rst be removed. Remove the 4 nuts and
washers retaining the #1 check assembly. Remove the
#1 check assembly from the body.
6. To remove the #2 check assembly, remove the 7 nuts,
washers and the #2 check retaining ring. Grasp the check
assembly by the stem and remove from valve.
7. Remove all 6 bolts, washers and o-rings from the check
assembly (See “Check Assembly” illustration). Separate re-
tainer from check assembly to expose seal ring for inspection.
8. Inspect the rubber seal ring for cuts or embedded debris. If
the reverse side of the seal ring is unused, it is possible to
invert the seal ring. This would be considered a temporary
solution to xing a fouled check and should be replaced
with a new seal ring as soon as possible.
9. Inspect valve cavity and seating areas. Remove any debris.
10. Reverse the above procedures to reinstall check assemblies.
Lubricate seat o-rings to hold them in place while reinstall-
ing seat. Place washers on studs and tighten retaining nuts
evenly.
11. Reinstall access cover and grooved coupling.
NOTE: If any portion of the seat assembly is damaged or missing
or if the seat sealing rib is damaged in any way, do not attempt to
eld repair it. Contact your local ZURN WILKINS representative
for assistance.
CHECK ASSEMBLY
All Model 350 Double Check Valve Backow Preventers must be
inspected and maintained by licensed personnel at least once
a year or more frequently as specied by local codes. Replace-
ment of worn or damaged parts must only be made with genuine
“ZURN WILKINS” parts.
GENERAL MAINTENANCE
1. Clean all parts thoroughly with water after disassembly.
2. Carefully inspect rubber seal rings and o-rings for damage.
3. Test unit after reassembly for proper operation (refer to
“TESTING PROCEDURES”).
SEAT ASSEMBLY
SEAL RING
O-RING
(BOLT)
RETAINER
WASHER
BOLT
®
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