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 .