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5

Servicing First and 

Second Checks

Series 994/994RPDA  

8" and 10" (200 – 250mm)

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.  

#1 CHECK

     Using a 

9

16

" socket wrench or nut driver, remove the four nuts  

from the #1 check studs 

(see fig. 1)

. Using two hands, place  

them at 12 o’clock and 6 o’clock, wiggle the check assembly free. 

Remove through access port with back of clapper first with spring 

end down. Pull check assembly out of main body. Inspect seats 

and clap per seal ing surfaces. (See page 6.)

     #2 CHECK

     After loosening bolts with a 

9

16

" socket, remove bolts completely. 

Using the centerline access bar, spin the check assembly from the 

9 o’clock position to the 12 o’clock position, then (without letting 

go of the ac cess bar) push the cam assembly slightly down stream 

so that the clapper is now parallel to the valve body. Now bring 

the check as sem bly through the check retaining wall. Leave the 

check assembly par al lel to the valve body. Pull the check assem-

bly through the access port.

3.  Using a 

3

8

" nut driver or a piece of small diameter pipe, place 

on the check arm torsion spring and move away from and move 

away from and around the torsion spring retaining bracket so as 

to relieve the tor sion spring tension. This will allow the check arm 

to move free ly, en abling you to inspect the clapper face and check 

seat. Thor ough ly clean the seat area and clapper sealing surfaces, 

check arms, and O-rings for damage, nicks, and debris. If dam-

aged, in stall a new check as sem bly and or O-ring.

4.  Before reinstallation of check assembly, thoroughly clean O-ring 

groove and lubricate O-ring with F.D.A. approved lubricant.

Figure 1

Check Studs

Check Studs

Figure 3

#2 Cam-Check DC & RP

Figure 2

#1 Cam-Check RP

Figure 4

Removing Check Assemblies (Before servicing 

be 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

” all-thread rod through the spring retaining  

plate, Screw the threaded rod into the holes (#4) at the base of 

spider (#5 next to shaft). Be sure to use two nuts on the threaded 

rod to tighten them into the holes. The depth of the threaded 

holes should be approximately 

1

2

". This operation will require you 

to use two piec es of threaded rod (see drawing below).

4.  Compressing the spring. To do so you need to loosen the top 

3

8

” 

nut and back it off without unthreading the threaded rod from the 

spider. Place a box end wrench or crescent wrench on the 

3

8

” 

nut clos est to the spring retaining plate and tighten. Tighten both 

thread ed and nut evenly; put a few turns on one threaded rod nut 

and a few turns on the other.

5.  During compression, the clapper will slowly move up, away from 

the seat. To examine the seat, continue spring compression un til 

the clapper has moved approximately 1" from the seat. This will 

allow de bris to be removed and or the seat to be examined.

6.  To unload the spring compression, loosen the all-thread and then 

double nut the all-thread and unscrew the rod from the spider and 

shaft base.

1. Shaft
2. Spring retaining plate
3. Spring
4. 

3

8

” threaded hole (maintenance)

5. Spider
6. Spider retaining bolt
7. Seat ring
8. Clapper to shaft bolt
9. Seat ring retainer

1

2

3

4

5

6

3

8

 - 16 

var.

Threaded Rod

7

8

9

#1 Check 

Valve 8" & 10" 

(200 & 250mm)

DANGER

!

Use extreme caution when servicing the first check!

Servicing the  

First Check 

To inspect the seat and clean the seat and 

clapper washer:

To disassemble the first check, you will need 

the following:

• Two pieces of 

3

8

" threaded rod (approximately 14" long)

• Adjustable crescent wrench
• Pipe wrench or channel lock pliers

Содержание 994 Series

Страница 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...

Страница 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...

Страница 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...

Страница 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...

Страница 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...

Страница 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...

Страница 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 ...

Страница 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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