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 Backflow Preventers must be performed by qualified, 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 backflow 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 Backflow 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 Backflow Preventer, flush the line thor
-
oughly to remove all debris, chips and other foreign matter. If required, a strain
-
er should be placed upstream of the Backflow Preventer. CAUTION: Do not use a
strainer in seldom used emergency waterlines such as fire 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 flood 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 field 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 Backflow Pre
-
venter may be installed outdoors only if the
device is protected against freezing condi
-
tions. Exposure to freezing c
o
nditions 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 backflow 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 first
and second check valves and thor
-
oughly flush 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 flowing
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
