User Guide

6
Service Procedures for Series 850, 856, 870V & 876V 2
1
⁄2"-10"(65-250mm)
MAINTENANCE MANUAL SERIES 850, 856, 870V & 876V 2
1
⁄2"- 10" (65 – 250mm)
Check Valve Disassembly and Reassembly
1. Spring Module Removal
a. Slowly close outlet shutoff valve and inlet shutoff valve.
Bleed residual pressure by opening #4, #3, and #2 test cocks
(See Page 11 for test cock location).
b. Remove cover bolts, removing the two bolts last that are located
next to the retainer pin. Remove cover.
NOTE: Spring module is positioned in the body by the cover.
Spring is captured in the module.
c. Refer to Page 11-12. Remove pivot bearing (Item 13) from the
upper spring retainer of the spring module. Inspect pivot bearing
(Item 13) and bearing socket (Item 15). Small hole in bearing socket
indicates replacement is required. Remove retaining clip (Item 5.1)
from groove on one end of the load pin (Item 7). Hold spring module
with one hand while sliding out load pin (Item 7) from arm (Item
4). Lift out spring module and inspect for wear or damage. Replace
spring module if necessary.
2. Check Disk Removal
a. Remove jam nut (Item 16) and washer (Item 17) from check disc
stem threads. Lift the arm and remove the check disc (Item 6).
Inspect sealing surface for debris or damage. Replace check
disc if necessary.
NOTE: When jam nut (Item 16) is tight, check disc
is designed to “wobble.”
3. Seat Ring Assembly Removal
NOTE: Remove the seat ring assembly only if the seat ring (Item 3)
or arm (Item 4) appear to be worn or damaged.
a. Remove locknuts (Item 3.4). (See above drawing).
NOTE: When reassembling, tighten locknuts to 40-50 in./lbs. If leaking
occurs around bolt, further tighten until leaking stops. Do not
over tighten.
b. Remove seat ring assembly.
c. Remove retaining clip (Item 5) from one end of the swing pin
(Item 4.2). Hold arm (Item 4) while sliding out swing pin (Item 4.2).
Inspect bushings (Item 4.1) and pin (Item 4.2) for wear or damage.
Replace if necessary. Inspect gasket (Item 3.1) for debris and/or
damage. Replace if necessary.
NOTE: Reverse the previous procedure to reassemble the compo-
nents. Seat ring will only fit into body one way. Check align-
ment of seat ring if studs do not align with body holes. Gasket
is also non-symmetric. Both seat ring and gasket have a notch
that indicates non-symmetric hole. Clean all parts thoroughly
with clean water before reassembly. Reassemble and bleed
test cocks #4, and #3. Repressurize the assembly and test to
ensure proper operation.