Installation Guide

 Installation  Testing  Maintenance Instructions
CAUTION: Do not pipe the relief valve
solidly to a oor drain, sewer or sump.
4. Install valve at least 12 inches above
surrounding ood level.
5. Always consult local codes for installa-
tion methods, approvals and guidance.
OUTDOOR INSTALLATION
Model 975XL2 Backow 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.
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.
INDOOR INSTALLATION
Indoor installation is preferred in areas that
are subject to freezing conditions. All the
basic installation instructions apply to such
installations.
PARALLEL INSTALLATION
Where uninterrupted service from a single
meter connection must be maintained, two
or more Backow Preventers may be con-
nected in parallel. All the basic installation
instructions apply to parallel installation. Be
sure to allow adequate room between the
units for testing and repair.
PLACING THE DEVICE IN SERVICE
After the installation of a Model 975XL2 has
been completed, place the unit in service
as follows:
975XL2 REDUCED PRESSURE PRINCIPLE
1. Start with both shut-off valves closed.
Slowly open the inlet shut-off valve un-
til the backow preventer is completely
pressurized. A brief discharge from the
relief valve may occur while the device
is pressurizing. The discharge should
cease by the time the shut-off valve
is fully open. Device should function
properly. If the discharge does not
stop, refer to "MAINTENANCE IN-
STRUCTIONS" for repair procedures.
2. After the device has been pressurized,
vent all trapped air from both check
valve by slightly opening each of the
four test cocks.
3. Slowly open the downstream shut-off
valve. The Model 975XL2 Reduced
Pressure Principle Backow Preventer
is now in service.
4. If "spitting" or intermittent discharges
from the relief valve are noted, it could
be a result of pressure uctuation
and/or a water hammer condition in
the system. If such conditions exist,
install water pressure reducing valves
or water hammer shock arresters in
compliance with industry standards as
needed.
5. After the Model 975XL2 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. If the relief
valve fails to operate properly, inspect
the sensing passage for clogging
(see "MAINTENANCE INSTRUC-
TIONS"). Clean rubber seals of all
debris and place unit back in service.
CAUTION: Installation of Backow Pre-
venters must be performed by qualied,
licensed personnel. The installer should
be sure the proper device has been se-
lected for the particular installation. Faulty
installation could result in an improperly
functioning device.
WILKINS Model 975XL2 Reduced Pres-
sure Principle Backow Preventers are for
use on potable water lines where a health
hazard could exist if a backow situation
were to occur.
Proper performance is dependent upon
following these installation instructions
and prevailing governmental and industry
standards and codes. Failure to do so,
according to WILKINS Limited Warranty
"...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.
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 arresters
and/or pressure relief valves should be
installed downstream of the device.
1. Before installing a Model 975XL2
Backow Preventer, ush the line
thoroughly to remove all debris, chips
and other foreign matter. If required,
a strainer 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. The Model 975XL2 must be installed
in a horizontal position to provide
proper operation of the relief valve.
3. Provide adequate space around the
installed unit so that the test cocks will
be accessible for testing and servicing.
If installation of a Model 975XL2 is in a build-
ing, provide a suitable drain arrangement
to drain off spillage from the relief valve. An
air gap at least two times the pipe diameter
must be provided between the relief valve
and the drain piping to prevent a cross-
connection.
12" MIN
30" MAX
PROTECTIVE
ENCLOSURE
OPTIONAL
WATER METER
INLET SHUT-OFF
AIR GAP
DRAIN
DIRECTION OF FLOW
Model 975XL2
LEAD-FREE*
Reduced Pressure Principle Assembly (1/4" - 2")
*This product contains a weighted average lead content less than 0.25% for wetted surfaces.
*Meets the requirements of NSF/ANSI 61
®
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