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4

Servicing First and Second Checks

Series 994/994RPDA 4" and 6" (100 – 150mm)

Removing Check Assemblies (Before servicing 

be sure shutoff valves are closed)

Figure 3

Figure 2

Figure 4

B

A

C

Screwdriver

#2 Check

#1 Check

#1 Check 2

1

2"

 – 6" (65 – 150mm)

Spring

Cam Arm

Roller

Clapper

Seat

O-ring Seal & 

Groove

#2 Check

Spring

Cam Arm

Roller

6” Only

Clapper

O-ring Seal & Groove

Seat

Lug

O-ring Seal & Groove

Figure 5A

6" (150mm)  

2nd Check RP

Valve Outlet Flange Threaded 

Stud on Flange

Cam Bar Open Pin

Figure 5B

Cleaning Position

1.  Slowly open all ball valves to relieve air and water pressure.   

Loosen bolts on groove coupler and remove groove couple 

and cover plate from valve body.

2.  Remove #1 Check Assembly by using your hands to un screw  

(turn counterclockwise) Check and remove through top access 

port. Do not use Check Arm as a handle to unscrew. If Check 

can not be loosened by hand, insert a long screwdriver between 

valve body and Check 

(see figure 2)

. Gently apply pressure 

against the Check until loos ened. Fin ish unscrewing by hand. Un-

screw #2 Check (turn counter-clock wise) by placing along screw-

driv er across lugs and applying pres sure to loosen #2 Check. 

Fin ish  un screw ing  by  hand.

3.  To clean #1 Check 6" (150mm) only, 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 down-

ward 

(figure 5A)

. Tighten 

1

/

4

" (8mm) nut on stud to secure cam 

bar. Slowly pull the assembly outward to open check allowing ex-

posure of the seat clapper area for clean ing. To clean #2 Check, 

lift Cam Arm and hold in open po si tion. Raise clapper so that the 

end of the Check Arm rests between roller and clapper 

(fig ure 

5B)

. Thoroughly clean the seat area and clapper sealing sur fac es 

of both Checks. In spect seats, clap per sealing surfaces, Check 

Arms, and O-rings for damage, nicks, and debris. If not dam-

aged, gently close the clap per. If damaged, install a new Check 

assembly and/or O-ring.

4.  Before reinstallation of Checks, thoroughly clean O-ring groove 

and lubricate O-ring with FDA approved lubricant. Insert and 

thread #2 Check first and then #1 Check. #2 Check should be 

tightened by in sert ing a long screwdriver between lugs to tighten 

firm ly 

(see fig ure 2)

. Do not over tighten. Tighten #1 Check firmly 

by hand only. Replace cover plate, clean groove coupler gas ket 

and groove. Replace groove coupler. Repres-surize and bleed air 

from all test cocks.

Figure 1

7

Note: See page 6 for additional 1

st

 check servicing

Summary of Contents for 994 Series

Page 1: ... with local codes but at least once per year or more as service conditions warrant Corrosive water conditions and or unauthorized adjustments or repair could render the product ineffective for the service intended Regular checking and cleaning of the product s internal components helps assure maximum life and proper product function WARNING Read this Manual BEFORE using this equipment Failure to r...

Page 2: ...may occur due to wa ter supply pressure fluc tu a tion during static no flow con di tions A check valve may be re quired ahead of the backflow preventer 7 ASSEMBLY If the backflow preventer is disassembled dur ing in stal la tion it MUST be reassembled in its proper order The gate valve with the test cock is to mounted on the inlet side of the back flow pre ven ter The test cock must be on the inl...

Page 3: ...from un nec es sary foul ing CAUTION Do not install a strainer ahead of the backflow pre ven ter on seldom used emergency water lines i e fire sprinkler lines The strainer mesh could potentially become clogged with debris pres ent in the water and cause water blockage during an emer gen cy Start Up E The downstream shutoff should be closed Open up stream slow ly fill the valve and bleed the air th...

Page 4: ...osen 2 Check Fin ish un screw ing by hand 3 To clean 1 Check 6 150mm only 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 down ward figure 5A Tighten 1 4 8mm nut on stud to secure cam bar Slowly pull the assembly outward to open check allowing ex posure of the seat clapper area for clean ing To clean 2 Che...

Page 5: ... certain shutoff valves are closed 1 After removing the first check from the backflow valve body place on a flat surface with the coil spring facing up 2 In order to gain access to the seat and clapper rubber ring you must compress the spring 3 that surrounds the clapper shaft 1 To do so you must place the 3 8 threaded rod through two holes of the spring retaining plate 2 3 After placing the 3 8 a...

Page 6: ...emove the body install a new relief valve assembly 3 Position the diaphragm on the piston assembly so that it is fac ing up as shown in Figure 8 4 Now fold the top ribbed edge of the diaphragm inward grasp the sleeve with the ribbed edge up and slide the sleeve down over the piston assembly as shown in Figure 8 5 While still holding the sleeve slide it up over the diaphragm and using your thumb in...

Page 7: ...art Test 7 Open VA then slowly open VB no more than 1 4 turn When relief valve drips push the hold button for 2 seconds Record reading must be 2 PSID or more Push Stop Test 8 Close VA and VB Test No 2 Test No 2 Check Valve 9 Install bypass hose between VA and TC 4 Open VA then bleed air by loosening hose connection at TC 4 Tighten hose connection Close VA Push Start Test 10 Open VB to reestablish ...

Page 8: ...hin the warranty period the Company will at its option replace or recondition the product without charge THE WARRANTY SET FORTH HEREIN IS GIVEN EXPRESSLY AND IS THE ONLY WARRANTY GIVEN BY THE COMPANY WITH RESPECT TO THE PRODUCT THE COMPANY MAKES NO OTHER WARRANTIES EXPRESS OR IMPLIED THE COMPANY HEREBY SPECIFICALLY DISCLAIMS ALL OTHER WARRANTIES EXPRESS OR IMPLIED INCLUDING BUT NOT LIMITED TO THE ...

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