Installation
Testing
Maintenance Instructions
Model 450 & 450DA
Double Check Valve Assembly (4” & 6”)
Double Check Detector Assembly (4” & 6”)
a company
®
®
WILKINS, a ZURN company
1747 Commerce Way, Paso Robles, CA 93446 Phone:805/238-7100 Fax:805/238-5766
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 particular
installation. Faulty installation could result in an improperly functioning device.
WILKINS Model 450 Double Check Valve 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 450 Backflow Preventer, flush the line thoroughly to
remove all debris, chips and other foreign matter. If required, a strainer 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 6 inches above surrounding flood level.
4. Always consult local codes for installation methods, approvals and guidance.
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 completely pressur
-
ized.
2. When the unit has been pressurized,
vent any trapped air by slightly opening
each of the four test cocks.
3. Slowly open the downstream shut-off
valve. The Model 450 Double Check Valve
assembly is now in service.
4. After the Model 450 has been prop-
erly installed, test the device (see “TEST
PROCEDURES”). If the device fails the
test, remove the first and second check
valves and thoroughly flush the device.
Clean rubber and seats of all debris and
place unit back in service.
(Patent No. 5,913,331)
PROTECTIVE
ENCLOSURE
6" MIN.
WILKINS VALVE
SETTER MJFS
DIRECTION OF FLOW
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 450 Backflow Preventer may be installed outdoors only if the device is
protected against freezing conditions. 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.
TYPICAL HORIZONTAL ORIENTATION
Proposition 65 Warning This product contains chemicals known to the State of California to cause cancer or birth defects
or other reproductive harm.
