Watts 775 Series Installation and user guide

Series

775/775DCDA

Double Check Backflow Preventer

Double Check Detector Assemblies

Sizes: 3" - 8"

• Installation • Service

• Repair Kits • Maintenance

LIMITED WARRANTY: Watts Regulator Company warrants each prod-

uctagainstdefectsinmaterialandworkmanshipforaperiodofoneyear

from the date of original shipment. In the event of such defects within

thewarrantyperiod,theCompanywill,atitsoption,replaceorrecondi-

tion the product without charge. This shall constitute the exclusive

remedy for breach of warranty, and the Company shall not be respon-

sible for any incidental or consequential damages, including without

limitation,damagesorothercostsresultingfromlaborcharges,delays,

vandalism,negligence,foulingcausedbyforeignmaterial,damagefrom

adverse water conditions, chemicals, or any other circumstances over

whichtheCompanyhasnocontrol.Thiswarrantyshallbeinvalidatedby

any abuse, misuse, misapplication or improper installation of the

product. THE COMPANY MAKES NO OTHER WARRANTIES EXPRESS

OR IMPLIED EXCEPT AS PROVIDED IN THIS LIMITED WARRANTY.

For field testing procedure, send for IS-TK-DP/DL,

IS-TK-9A, IS-TK-99E and IS-TK-99D.

For other repair kits and service parts, send for

PL-RP-BPD.

For technical assistance, contact your local Watts

representative on back page.

N775/N775DCDA Backflow Preventers are

identical in construction to 775/775DCDA Series

except include short radius elbows between

backflow preventer flange and gate valve flange.

RP/IS-775/775DCDA

IMPORTANT: Inquire with governing authorities

for local installation requirements.

NOTE: For Australia and New Zealand: Pipeline

strainers should be installed between the up-

stream shutoff valve and the inlet of the

backflow preventer.

CALIFORNIA PROPOSITION 65 WARNING

WARNING: This product contains chemicals

known to the State of California to cause cancer

and birth defects or other reproductive harm.

(Installer: California law requires that this

warning be given to the consumer.)

Insert lid bolts in holes

provided to remove 1st check

aaa

Basic Installation Instructions

Installation Note:

The flange gasket bolts for the

gate valves should be retight-

ened during installation as the

bolts may have loosened due to

storage and shipping.

Check with local authorities for installation requirements. If

installing on a fire protection system be sure to purge air

from the system. Fill system slowly with all inspector test

valves open.

Pipe lines should be thoroughly flushed to remove foreign

material before installing the unit. A strainer should be in-

stalled as shown, ahead of the backflow preventer to prevent

discs from unnecessary fouling.

CAUTION: Do not install a strainer when backflow preventer

is used on seldom-used water lines which are called upon

during emergencies, such as fire sprinkler lines, etc.

It is important that Series 775 be tested periodically in compli-

ance with local codes, but at least once a year or more often,

depending upon system conditions.

775 Series for Retrofit Installations

Watts 775

12” min.

Refer to

Local Codes

Vault Installation

Vertical Flow

12” min.

Refer to

Local Codes

Watts 775

Watts Series 775 Double Check Valve

#2 Test Cock

#3 Test Cock

#4 Test Cock

Outlet

Shutoff

Valve

Second Check

First

Check

#1 Test Cock

Inlet

Shutoff

Valve

Watts Series 775 Installation Instructions

Installation

A. Series 775 may be installed in a

horizontal or vertical flow up posi-

tion. The shutoff valve with the test

cock is to be mounted on the inlet

side of the backflow preventer. The

test cock is on the inlet side of the

shutoff valve.

B. The 775 should always be installed

in an accessible location to facilitate

testing and servicing. Check state

and local codes to insure that the

backflow preventer is installed in

compliance, such as the proper

height above the ground. The back-

flow preventer must be supported

and is not designed to carry full

weight of the stand pipe.

C. Backflow preventers should never

be placed in pits unless absolutely

necessary and then only when and

as approved by local codes. Con-

sult your local or state plumbing or

health inspector. Watts recom-

mends installation indoors or above

ground in an insulated enclosure.

Start Up

D. The downstream shutoff should be

closed. Open upstream slowly, fill

the valve and bleed the air through

Test cock 2, 3 and 4. When valve is

filled, open the downstream shutoff

slowly and fill the water supply sys-

tem. This is necessary to avoid wa-

ter hammer or shock damage.

E . Two or more valves can be piped in

parallel (when approved) to serve a

large supply pipe main. This type of

installation is employed where in-

crease capacity is needed beyond

that provided by a single valve and

permits testing or servicing of an in-

dividual valve without shutting down

the complete line.

The number of assemblies used in

parallel should be determined by the

engineer’s judgement based on the

operating conditions of a specific in-

stallation.

Above Ground

*Insulated Enclosure

Indoor Installation

Watts 775

*For additional information on Watts insulated enclosures send for ES-WB or ES-WBT.

12” min.

Refer to

Local Codes

12” min.

Refer to

Local Codes

aaa

Removing Checks

Before Servicing Be Certain Shutoff Valves Are Closed

The assembly may be locked open by aligning the holes

in the cam bar and hinge arms and inserting a rod (see

Fig. 8, pg.6). If the clapper needs to be replaced or re-

paired, please refer to check disassembly instructions

and figures 6 through 10 on page 6. Caution: If the seat

is damaged, replace complete check module. If replace-

ment is not required, please continue.

To clean No. 2 check, lift arm and hold in open position

(see Fig. 9, pg. 6). Thoroughly clean the seat area and

clapper sealing surfaces of both checks. Rinse checks

and o-rings thoroughly.

Installation of Cam-Checks

Before installing checks, thoroughly clean o-ring grooves

and lubricate o-rings with FDA approved lubricant. Insert

and thread No. 2 check first and then No. 1 check. No. 2

check should be tightened by inserting a long screwdriver

between lid bolts inserted in seat ring to tighten. Prior to

filling the system, please ensure that lid bolts are tightened

(50 ft.lbs.), cover plate is properly secured, and test cocks

are open.

Start Up: The downstream shutoff should be closed. Open

upstream slowly, fill the valve and bleed the air through test

cocks 2, 3 and 4. When valve is filled, open the down-

stream shutoff slowly. This is necessary to avoid water

hammer or shock damage to the water system.

Figure 2

No. 2 Cam Check

(6" and 8" models only)

Place yourself so that the water flow through the valve is

left to right.

1. Shut down water system and lock out system if possible.

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

After pressure is relieved, loosen bolts on groove coupler

and remove groove coupler and cover plate from valve body.

2. Remove No. 1 check assembly by unscrewing (turn counter-

clockwise) check and remove through top access port. Do

not use arm as a handle to unscrew check. Insert lid bolts in

1st check seat ring (see Fig. 1), insert a long screwdriver or

pry bar between lid bolts. Gently apply pressure against the

bolts and turn seat assembly counter clockwise moving

bolts hole to hole to maintain turning leverage (two addi-

tional bolts will eliminate need to move lid bolts from hole to

hole). Finish unscrewing by hand and remove from valve

body. Unscrew No. 2 check (turn counterclockwise) by plac-

ing a long screwdriver across lid bolts inserted in holes lo-

cated in the 2nd check seat ring, similar in method used to

remove 1st check and applying pressure to loosen No. 2

check. Finish unscrewing by hand.

3.To clean check assemblies, locate the check arm opening

stud on the outlet flange of the valve assembly, (6" and 8"

only). Slide the arm over the stud with the check threads fac-

ing downward (Fig. 2). Tighten a 1⁄4" nut on stud to secure.

Slowly pull the assembly outward to open check allowing

exposure of the seat and clapper contact area for cleaning.

Figure 1

No. 1 Cam Check

Figure 6

Valve outlet flange

Threaded stud on flange

775/775DCDA Repair Kits

First Check Kit

EDP No. Kit No. Size For use with /Model #'s

0888900 RK 775/775DCDA CK 1 3" - 4" 3" - 4" 775/775DCDA/N775/N775DCDA

0888901 RK 775/775DCDA CK 1 6" - 8" 6" - 8" 775/775DCDA/N775/N775DCDA

Kits include: Complete No. 1 Check Assembly with Check O-ring.

Second Check Kit

0888902 RK 775/775DCDA CK 2 3" - 4” 3" - 4" 775/775DCDA/N775/N775DCDA

0888903 RK 775/775DCDA CK 2 6" - 8" 6" - 8" 775/775DCDA/N775/N775DCDA

Kits include: Complete No. 2 Check Assembly with Check O-ring.

Cover Kit

0888904 RK 775/775DCDA C 3" - 4” 3" - 4" 775/775DCDA/N775/N775DCDA

0888905 RK 775/775DCDA C 6" - 8" 6" - 8" 775/775DCDA/N775/N775DCDA

Kit includes: Cover, Grooved Coupler & Gasket.

First Check Rubber Parts Kit

0888906 RK 775/775DCDA RC1 3" - 4" 3" - 4" 775/775DCDA/N775/N775DCDA

0888907 RK 775/775DCDA RC1 6" - 8" 6" - 8" 775/775DCDA/N775/N775DCDA

Kit includes: First Check Assembly O-ring and Check Disc

Second Check Rubber Parts Kit

0888908 RK 775/775DCDA RC2 3" - 4" 3" - 4" 775/775DCDA/N775/N775DCDA

0888909 RK 775/775DCDA RC2 6" - 8" 6" - 8" 775/775DCDA/N775/N775DCDA

Kit includes: Second Check Assembly O-ring and Check Disc

Rubber Total Parts Kit

0888910 RK 775/775DCDA RT 3" - 4" 3" - 4" 775/775DCDA/N775/N775DCDA

0888911 RK 775/775DCDA RT 6" - 8" 6" - 8" 775/775DCDA/N775/N775DCDA

Kit includes: First and Second Check Assembly O-ring, and First and Second Check Disc

Watts Series 775/775DCDA 3" - 8"

Figure 3

Figure 4

Figure 5

No. 1 Cam-Check

Assembly

No. 2 Cam-Check

Assembly

1st Cam-check

O-ring (removable)

2nd Cam-check

O-ring (removable)

Groove Coupler

Gasket

Ball Valve

Cover Plate

No. 1 Check Assembly

No. 2 Check Assembly

Check Parts and Disassembly

Before reinstallation of check assembly, thoroughly clean o-ring groove and lubricate o-ring with FDA approved lubricant.

Item No. Part Description

1. First Check O-ring (removable)

2. Clapper Assembly (removable)

3. Clapper Retaining Plate Screws (removable)

4. Clapper Retainer Plate (removable)

5. Clapper Disc (removable)

6. Pivot Arm Pin (removable ) Two c-clips

7. Second Check O-ring (removable)

Note: Align holes and

insert pin or small

screwdriver to hold in

open position.

Figure 7

Figure 8

Figure 9

Figure 10

Check Disassembly

Please use caution when disassembling check.

Check Parts

Figure 7

Using a thin rod or screwdriver, lift the bar

up so that the clapper is free to swing up-

wards away from the seat.

Figure 8

Using your free hand, swing the clapper

open until the roller is almost to the free

end of the bar. Align the maintenance

lockout holes in the bar and the hinge

arms. Secure the check assembly in the

maintenance position by inserting a rod or

thin screwdriver through the lockout holes.

Figure 9

Remove one c-clip from the center pivot

pin. Withdraw the center pivot pin from the

clapper and the hinge arms. Remove the

clapper assembly from the check assembly

module. Remove the retainer screws. Note:

You may replace this item as an assembly or

you may continue and replace only the disc.

Figure 10

Disassemble the clapper by removing four

screws, disc retainer and the sealing disc.

Disc may be flipped if sealing surface

is damaged.

For additional testing information send for IS-TK-DP/DL, IS-TK-9A and IS-TK-99E

Testing - Double Check Valve Assemblies

The following Test Procedure is one of several that is recognized throughout the United States for verifica-

tion of the functioning of Backflow preventers.

The following procedure is not a specific recommendation. The Watts series of test kits are capable of per-

forming any of the recognized Backflow test procedures.

A. Flush all test cocks.

B. Turn tester on (before connecting hoses). Tester must read all

zeroes. Close VA and VB.

Test No. 1 - Test No. 1 Check Valve

Install high side hose between TC #2 and tester connection A.

Install low side hose between TC #3 and tester connection B.

3. Open TC #2 then VA, bleed hose, then close VA.

4. Open TC #3 then VB, bleed hose, then close VB.

5. Install a bypass hose between VB and TC #1. Open TC #1

and bleed by loosening hose connection at VB. Tighten hose

connection, fully open VB.

Push - Print Head (wait) then Push - Star Test

6. Close shutoff valve #2 then #1.

7. Slowly open VA and loser high side pressure about -2 PSID

below the low side pressure (differential reading about -2.0

PSID). Close VA. If reading is maintained, record as “tight”.

If reading returns to 0 and the pressure A increases to pres-

sure B, the check is recorded as leaking. If the reading re-

turns to + PSID, No. 2 shutoff valve is leaking excessively,

and must be replaced to test the valve.

8. Close all test cocks, remove hoses from TC #2 and TC #3

and TC #1. reopen shutoff valve #1.

Proceed to Test No.2.

Push - Stop Test.

Test No. 2 - Test No. 2 Check Valve

Install high side hose between TC #3 and tester connection A.

2. Install low side hose between TC #4 and tester connection B.

3. Open TC #3 then VA, bleed hose, then close VA.

4. Open TC #4 then VB, bleed hose, then close VB.

5. Install a bypass hose between VB and TC #1. Open TC #1

and bleed by loosening hose connection at VB. Tighten hose

connection, fully open VB.

Push - Start Test

6. Close shutoff valve #1.

7. Slowly open VA and lower high side pressure about -2 PSID

below the low side pressure (differential reading about -2.0

PSID). Close VA. If reading is maintained, record as “tight”.

If reading returns to 0 and the pressure A increases to pres-

sure B, the check is recorded as leaking. If the reading re-

turns to + PSID, No. 2 shutoff valve is leaking excessively,

and must be replaced to test the valve.

Push - Stop Test.

Watts 775 Watts 775

Watts TK-DP Watts TK-DP

Test 1 Test 2

VB VA VB

It is important that this device be tested periodically in compli-

ance with local codes, but at least once per year or more as ser-

vice conditions warrant. If installed on a fire sprinkler system

all mechanical checks, such as alarm checks, single checks

and backflow preventers should be inspected internally every

one to five years in accordance with NFPA 13 A and NFPA 25

This manual suits for next models

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