774X DCDA 774X DCDA 21/2”, 6”, 8”21/2”, 6”, 8”

Modification OverviewModification Overview Production began in 1998.Production began in 1998. The 2 ½” 774X DCDA was discontinued in The 2 ½” 774X DCDA was discontinued in

2003.2003. The 6” and 8” sizes were discontinued in The 6” and 8” sizes were discontinued in

2006.2006. All “X” assemblies use check modules that All “X” assemblies use check modules that

are one size smaller than the pipe size.are one size smaller than the pipe size. * Example: 8” size assembly uses 6” parts* Example: 8” size assembly uses 6” parts

Single Access Cover RemovalSingle Access Cover Removal Cover is secured by a Cover is secured by a

grooved coupling.grooved coupling. Cover has no spring Cover has no spring

load.load.

Check Valve RemovalCheck Valve Removal

Check valve modules Check valve modules are called “Cam are called “Cam Checks”.Checks”.

Checks are o-ring Checks are o-ring sealed and threaded sealed and threaded into body.into body.

#1 Check must be #1 Check must be removed before #2 removed before #2 can be removed.can be removed.

Check Valve RemovalCheck Valve Removal Cam checks unscrew Cam checks unscrew

counterclockwise by counterclockwise by hand “if possible”.hand “if possible”.

*Do not use cam arm *Do not use cam arm as a handle to as a handle to unscrew.unscrew.

Check Valve RemovalCheck Valve Removal If too tight, place a If too tight, place a

drift punch or solid drift punch or solid rod (long screwdriver) rod (long screwdriver) in one of the holes on in one of the holes on the outer edge of the the outer edge of the check module.check module.

Tap with hammer in Tap with hammer in correct direction correct direction (counterclockwise) to (counterclockwise) to loosen.loosen.

Check Valve Removal NotesCheck Valve Removal Notes There are “special There are “special

tools” available to tools” available to help remove check help remove check modules.modules.

Check Seat RemovalCheck Seat Removal Check seats are part Check seats are part

of each module and of each module and can not be removed.can not be removed.

If the seat is If the seat is damaged, the damaged, the complete check complete check module will need to module will need to be replaced.be replaced.

Check Disc Inspection 6”Check Disc Inspection 6” The disc assembly is The disc assembly is

part of the module part of the module and can not be and can not be removed.removed.

For inspection and For inspection and cleaning, lift the cam cleaning, lift the cam arm and hold in open arm and hold in open position.position.

*Raise the clapper so *Raise the clapper so that the end of the that the end of the cam arm rests cam arm rests between the roller between the roller and clapper.and clapper.

Check Disc Inspection 8” Check Disc Inspection 8”

For inspection and For inspection and cleaning locate the cleaning locate the stud on the outlet stud on the outlet flange of the flange of the assembly.assembly.

Place the cam arm Place the cam arm hole on the stud and hole on the stud and open the check valve open the check valve so that the cam rests so that the cam rests between the roller between the roller and clapper.and clapper.

Check Valve Reassembly NotesCheck Valve Reassembly Notes Change and lubricate Change and lubricate

check o-ring.check o-ring. Install #2 check first Install #2 check first

then #1 check.then #1 check. # 2 check should be # 2 check should be

tightened with a long tightened with a long screwdriver.screwdriver.

Tighten #1 check Tighten #1 check firmly by hand only.firmly by hand only.

Lubricate the outside Lubricate the outside edge of the groove edge of the groove coupler gasket.coupler gasket.