ZURN 350AST Series User manual

Model 350AST(R) & 350ASTDA(R)
Double Check Valve Assembly (2-1/2", 3", 4" & 6")
Double Check Detector Assembly (2-1/2", 3", 4" & 6")
Installation Testing Maintenance Instructions
®
INSTALLATION INSTRUCTIONS
CAUTION: Installation of Backow Preventers must be performed by qualied, licensed
personnel. The installer should be sure the proper device has been selected for the par-
ticular installation. Faulty installation could result in an improperly functioning device.
ZURN WILKINS Model 350AST Series Assemblies are for use on potable water lines
where a health hazard does not exist in the event of a backow situation.
Damage to the device could result wherever water hammer and/or water thermal expan-
sion could create excessive line pressure. Where this could occur, shock arrestors, check
valves and/or pressure relief valves should be installed downstream of the device.
If installation is in a pit or vault, the Backow Preventer must never be submerged in
water because this could cause a cross-connection. Make sure that the pit or vault always
remains dry by providing ample drainage.
1. Before installing a Model 350AST Series Backow Preventer, ush the line thor-
oughly to remove all debris, chips and other foreign matter. If required, a strain-
er should be placed upstream of the Backow Preventer. CAUTION: Do not use a
strainer in seldom used emergency waterlines such as re lines.
2. Provide adequate space around the installed unit so that the test cocks will be
accessible for testing and servicing.
3. Install valve at least 12 inches above surrounding ood level.
4. Always consult local codes for installation methods, approvals and guidance.
5. Resilient seated shutoff valves are required to be installed on both the inlet and
outlet of the device to make eld testing possible.
INDOOR INSTALLATION
Indoor installation is preferred in areas that
are subject to freezing conditions. All the
basic installation instructions apply to such
installations.
OUTDOOR INSTALLATION
The Model 350AST Series Backow Pre-
venter may be installed outdoors only if the
device is protected against freezing condi-
tions. Exposure to freezing conditions will
result in improper function or damage to the
device. The installation location must be
kept above 32°F. All the basic installation
instructions apply.
PLACING THE DEVICE IN SERVICE
1. Start with both shut-off valves closed.
Slowly open the inlet shut-off valve
until the backow preventer is com-
pletely pressurized.
2. When the unit has been pressurized,
vent any trapped air by slightly open-
ing each of the four test cocks.
3. Slowly open the downstream shut-off
valve. The Model 350AST Series As-
sembly is now in service.
4. After the Model 350AST Series has
been properly installed, test the device
(see “TEST PROCEDURES”). If the
device fails the test, remove the rst
and second check valves and thor-
oughly ush the device. Clean rubber
and seats of all debris and place unit
back in service.
OUTDOOR INSTALLATION
Model 350AST
VERTICAL INSTALLATION
Vertical installation is acceptable in applica-
tions where inlet and outlet piping are owing
vertically upwards. All the basic installation
instructions apply to such installations. Con-
sult factory for approval status.
INDOOR INSTALLATION
Model 350ASTBG
PROTECTIVE
ENCLOSURE
DIRECTION OF FLOW
12" MIN.
30" MAX.
DIRECTION OF FLOW
DIRECTION OF FLOW
12" MIN.
30" MAX.
INDOOR INSTALLATION
Model 350ASTBG
LEAD-FREE*
*This product contains a weighted average lead content less than 0.25% for wetted surfaces.
(Patent No. 8,997,772)
!WARNING: Cancer and Reproductive Harm - www.P65Warnings.ca.gov
!ADVERTENCIA: Cáncer y daño reproductivo - www.P65Warnings.ca.gov
!AVERTISSEMENT: Cancer et néfastes sur la reproduction - www.P65Warnings.ca.gov

CHECK ASSEMBLY
SEAT ASSEMBLY
SEAL RING
O-RING
(BOLT)
SEAL RETAINER
WASHER
BOLT
CHECK HANDLE
O-RING (SEAT)
SIZE MODEL 350AST RUBBER ONLY MODEL 350ASTDA RUBBER ONLY (includes by-pass parts)
2-1/2" - 3" RK4-350ST RK4-350STDA
4" RK4-350ST RK4-350STDA
6" RK6-350ST RK6-350STDA
Testing Procedures
2ZURN WILKINS
1747 Commerce Way, Paso Robles, CA 93446 Phone:[phone] Fax:[phone]
2-1/2” - 6”
SPECIFICATIONS
Maximum working water pressure: 175 PSI
Maximum working water temperature: 140°F
Hydrostatic test pressure: 350 PSI
End connections: Flanged ANSI B16.1 Class 125
Grooved AWWA C606
MODEL 350AST SERIES ASSEMBLY
Equipment Required: Differential pressure gauge test kit.
TEST NO. 1 - TIGHTNESS OF #1 CHECK VALVE
REQUIREMENT:
The static pressure drop across check valve #1 shall be at least
1.0 psid. If test cock #3 is not at the highest point of the check
valve body, then a vertical tube must be installed on test cock #3
so that it rises to the top of the check valve body.
PROCEDURE:
1. Slowly open all 4 test cocks to remove any foreign material
and attach ttings.
2. Attach hose from the high side of the test kit to the #2 test cock.
3. Open test cock #2 and bleed all air from the hose and
gauge by opening the high side bleed needle valve. Close
high side bleed needle valve. If a tube is attached to test
cock #3, open test cock #3 to ll the tube. Close test cock
#3. Close #2 shut-off valve then close the #1 shut-off valve.
4. Hold gauge at same level as test cock #3 or water level in
tube. Slowly open test cock #3. Record the static pressure
drop across check valve #1 after gauge reading stabilizes
and water stops running out of test cock #3.
5. Close all test cocks, open shut-off valve #1 and remove test
equipment.
Note: If you are using the duplex gauge method to test the valve,
you may see both needles drop simultaneously during test due
to disc compression. The high side needle should eventually hold
2 psi below low side needle if check in not fouled.
TEST NO. 2 - TIGHTNESS OF #2 CHECK VALVE
REQUIREMENT:
The static pressure drop across check valve #2 shall be at least
1.0 psid. If test cock #4 is not at the highest point of the check
valve body, then a vertical tube must be installed on test cock #4
so that it rises to the top of the check valve body.
PROCEDURE:
1. Attach hose from the high side of the test kit to the #3 test
cock.
2. Open test cock #3 and bleed all air from the hose and
gauge by opening the high side bleed needle valve. Close
high side bleed needle valve. If a tube is attached to test
cock #4, open test cock #4 to ll the tube. Close test cock
#4. Close #1 shut-off valve.
3. Hold gauge at same level as test cock #4 or water level in
tube. Slowly open test cock #4. Record the static pressure
drop across check valve #2 after gauge reading stabilizes
and water stops running out of test cock #4.
4. Close all test cocks, slowly open shut-off valve #1 & #2 and
remove test equipment.
Repair Kits
Capacity thru Schedule 40 Pipe (GPM)
Pipe size 5 ft/sec 7.5 ft/sec 10 ft/sec 15 ft/sec
2-1/2" 75 112 149 224
3" 115 173 230 346
4" 198 298 397 595
6" 450 675 900 1351
8" 780 1169 1559 2339
10" 1129 1843 2458 3687
#1 SHUTOFF VALVE
#1 SHUTOFF VALVE#3 TEST COCK
#1 TEST COCK
#2 TEST COCK #4 TEST COCK
LOW SIDE BLEED
NEEDLE VALVE
LOW SIDE HOSE
HIGH SIDE BLEED
NEEDLE VALVE
HIGH SIDE HOSE
VENT HOSE
Proper performance is dependent upon licensed, qualied
personnel performing regular, periodic testing according to
WILKINS' specications and prevailing governmental & industry
standards and codes and upon following these installation in-
structions. Failure to do so releases WILKINS of any liability that
it might otherwise have with respect to that device. Such failure
could also result in an improperly functioning device.
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®

#1 CHECK ASSEMBLY
#2 PLATE RETAINER
#2 CHECK ASSEMBLY
GASKET
#1 RETAINER
Maintenance Instructions
3
FIGURE 1 FIGURE 2 FIGURE 3
Troubleshooting
All Model 350AST Series Backow Preventers must be inspected
and maintained by licensed personnel at least once a year or
more frequently as specied by local codes. Replacement of
worn or damaged parts must only be made with genuine “ZURN
WILKINS” parts.
GENERAL MAINTENANCE
1. Clean all parts thoroughly with water after disassembly.
2. Carefully inspect rubber seal rings and o-rings for damage.
3. Test unit after reassembly for proper operation (refer to
“TESTING PROCEDURES”).
NOTE: If any portion of the seat assembly is damaged or
missing or if the seating surface is damaged in any way, do not
attempt to eld repair it. Contact your local ZURN WILKINS
representative for assistance.
SERVICING CHECK VALVES
1. Close the outlet and then the inlet shut-off valves.
2. Open No. 2, 3 and 4 test cocks to release internal pressure.
Leave them open during check removal and reinstallation.
3. Loosen and remove the two nuts, bolts and gasket from the
grooved coupling around the access cover.
4. If the valve has a plastic retainer on the #1 check, grasp one
of the exposed ends, push down and then pull toward the #2
check. The retainer should “spiral” out of the groove around
the check.
the #2 check by locating one of the two spring-loaded
around the face of the check. Pinch the sides of
together and rotate the plates out of the body groove
nd retainer the same way.
Start by removing the hardware and o-rings from the back
check assembly (See “Check Assembly” illustration). Sepa-
g.
the seal ring for cuts or embedded debris. If the re-
side of the seal is unused, the seal ring can be inverted
temporarily until a new seal is obtained. Inspect seat
.
valve cavity and seating areas. Flush with water to
, Lubricate the #2 check o-ring, install in the body and
#4 test cock. Install the #2 check retainers into the body
one plate at a time, squeezing the spring ends together to
and install the #1 check. Close the #2 test cock.
the plastic retainer by inserting one end into the body
and then sliding your hand around the face of the retainer,
it into the groove as you go. The retainer will "snap" into
e the outside surface of the grooved coupling gasket.
access cover and grooved coupling, making sure the
the coupling touch each other. Close any remaining open
PROBLEM POSSIBLE CAUSES CORRECTIVE ACTION
1. LEAKING CHECK VALVES 1. Debris on seat or seal ring 1. Clean seat area
2. Damaged seat area 2. Replace check assembly
3. Damaged seat o-ring 2. Replace seat o-ring
4. Damaged bolt o-ring (s) on check retainer 4. Replace o-ring (s)
2. LOW OR NO FLOW 1. Device installed backwards 1. Verify ow direction arrow
2. Gate valves not fully open 2. Turn handles counterclockwise
3. Low supply pressure 3. Attach pressure gauge to test cock #1 and verify pressure
ZURN WILKINS
1747 Commerce Way, Paso Robles, CA 93446 Phone:[phone] Fax:[phone]
www.zurn.com
®
5. Remove the #2 check by locating one of the two spring-loaded
plate retainers around the face of the check. Pinch the sides of
the spring together and rotate the plates out of the body groove
one at a time. Remove the 2nd retainer the same way.
6. Always service the checks one at a time to avoid mixing
parts. Start by removing the hardware and o-rings from
the back of the check assembly (See “Check Assembly”
illustration). Separate the seal retainer from the assembly to
expose the seal ring.
7. Inspect the seal ring for cuts or embedded debris. If the re-
verse side of the seal is unused, the seal ring can be inverted
and used temporarily until a new seal is obtained. Inspect
seat o-ring and replace if cut or damaged in any way.
8. Inspect valve cavity and seating areas. Flush with water to
remove any debris.
9. Reassembly, Lubricate the #2 check o-ring, install in the body
and close the #4 test cock. Install the #2 check retainers into
the body groove one plate at a time, squeezing the spring
ends together to clear the stops on the face of the seat.
10. Lubricate and install the #1 check. Close the #2 test cock.
Install the plastic retainer by inserting one end into the body
groove and then sliding your hand around the face of the
retainer, pushing it into the groove as you go. The retainer
will "snap" into place when fully seated.
11. Lubricate the outside surface of the grooved coupling
gasket. Reassemble access cover and grooved coupling,
making sure the ends of the coupling touch each other.
Close any remaining open test cocks and place valve back
in service.

MODEL 350AST 6" (STANDARD & METRIC)
0
5
10
15
0400 800 1200 1600 2000
FLOW RATES (GPM)
PRESSURE LOSS (PSIG)
0
35
69
104
0.0 25.2 50.5 75.7 100.9 126.2
FLOW RATES (l/s)
PRESSURE LOSS (kpa)
MODEL 350ASTDA 6" (STANDARD & METRIC)
0
5
10
15
0500 1000 1500 2000
FLOW RATES (GPM)
PRESSURE LOSS (PSIG)
0
35
69
104
0.0 31.5 63.1 94.6 126.2
FLOW RATES (l/s)
PRESSURE LOSS (kpa)
MODEL 350AST 2 1/2", 3" & 4" (STANDARD & METRIC)
0
5
10
15
0200 400 600 800
FLOW RATES (GPM)
PRESSURE LOSS (PSIG)
0
35
69
104
0.0 12.6 25.2 37.9 50.5
FLOW RATES (l/s)
PRESSURE LOSS (kpa)
Performance Characteristics
ZURN WILKINS
1747 Commerce Way, Paso Robles, CA 93446 Phone:[phone] Fax:[phone]
®
Proper performance is dependent upon licensed, qualied personnel performing regular, periodic testing according to ZURN WILKINS'
specications and prevailing governmental & industry standards and codes and upon following these installation instructions. Failure to
do so releases ZURN WILKINS of any liability that it might otherwise have with respect to that device. Such failure could also result in
an improperly functioning device.
IS350AST (REV. F 1/19)
3" (80mm) 4" (100mm)
2 1/2" (65mm)
MODEL 350ASTDA 2 1/2", 3" & 4" (STANDARD & METRIC)
0
5
10
15
0200 400 600 800
FLOW RATES (GPM)
PRESSURE LOSS (PSIG)
0
35
69
104
0.0 12.6 25.2 37.9 50.5
FLOW RATES (l/s)
PRESSURE LOSS (kpa)
6" (150mm)
6" (150mm)
3" (80mm)
4" (100mm)
2 1/2" (65mm)
 Rated Flow (Established by approval agencies)
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