Installation Guide
Model 720A
Pressure Vacuum Breaker
(1/2", 3/4", 1", 1 1/4", 1 1/2" & 2")
Fig 1
INSTALLATION INSTRUCTIONS
CAUTION: Installation of Pressure Vacuum breakers must be performed by qualied,
licensed personnel. Faulty installation could result in an improperly functioning device.
The installer should be sure the proper device has been selected for the particular installation.
ZURN WILKINS Model 720A Pressure Vacuum Breakers are for use on irrigation, industrial,
and other non-potable services where a health hazard could exist if a backsiphonage situ-
ation were to occur. They must not be installed where backpressure may occur.
Proper performance depends upon following these installation instructions and prevailing
governmental and industry standards and codes. 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.
1. Before installing the ZURN WILKINS Model 720A Pressure Vacuum Breaker, ush the
lines thoroughly to remove all debris, chips and other foreign matter.
2. The Model 720A must be installed in a vertical position (see Fig. 1) to provide
proper operation of the air inlet valve.
3. Provide adequate space around the installed unit so that the test cocks will be
accessible for testing and servicing.
4. CAUTION: If installation of a Model 720A unit is in a building, provide a suit-
able drain arrangement to drain off spillage from the air vent.
5. Install valve at least 12 inches above the highest piping or water outlet down
stream of the Model 720A Pressure Vacuum Breaker.
6. Always consult local codes for installation methods, approvals and guidance.
7. The Model 720A Pressure Vacuum Breaker may be installed outdoors only if the
device is protected against any freezing conditions. Warning: do not block air vent
opening with insulation. Exposure to freezing conditions will result in improper
function or damage to the device. The installation location must be kept above 32°F.
PLACING THE DEVICE IN SERVICE
After the installation of a Model 720A Pressure Vacuum Breaker has been completed, place
the unit in service as follows:
1. Start with both shut-off valves and test cocks closed. Open the inlet shut-off valve until the
Pressure Vacuum Breaker is completely pressurized.
2. A brief discharge from the air vent may occur while the device is pressurizing. The
discharge should cease by the time the shut-off valve is in the full open position.
Installation Testing Maintenance Instructions
3. If the discharge does not stop, refer
to "MAINTENANCE INSTRUCTIONS".
Repressurize device as in Step 1. Device
should function properly.
4. Slowly open the No. 2 shut-off valve.
The Model 720A is now in service.
5. After the Model 720A has been prop-
erly installed, test the device. If the device
fails the test, refer to "MAINTENANCE
INSTRUCTIONS"
Drain Procedure for Freeze Protection
1. Turn off main shut-off (1) that supplies
water to the system.
2. Open both inlet and outlet drain valves
in the system (2 & 6). Open inlet and outlet
shut-off valves on the pressure vacuum
breaker (3 & 5) and all of the test cocks.
Leave all valves and test cocks in the half
open/half closed (45°) position to allow full
drainage of the ball valves and test cocks.
3. If you "blow out" the system down-
stream of the pressure vacuum breaker,
make sure the outlet drain valve (6) is open
and the pressure vacuum breaker shut-off
valve (5) is closed.
4. Connect an air hose to the outlet drain
valve (6) and inject an adequate volume of
air to remove all water from the downstream
portion of the system.
5. CAUTION: Open outlet shut-off valve to
the pressure vacuum breaker (5) and outlet
drain valve (6) to the half open/half closed
(45°) position after "blow out" process is
completed.
6. If drain valves (2 & 6) are not part of
the system, and if air pressure is not used
to "blow out" the system, the internal com-
ponents of the pressure vacuum breaker
should be removed for the duration of the
winter.
7. Leave all drain valves (2 & 6), shut-off
valves (3 & 5) and test cocks in the half
open/half closed position (45°) for the
duration of the winter to prevent freezing.
Caution: Be certain that main shut-off (1)
remains tightly closed to prevent relling of
the system. Also, the main shut-off valve
must be resilient seated to insure no leak-
age of water into the system.
TESTCOCKS (4)
1” 720A PVB
(25MM)
OUTLET SHUT OFF
VALVE (5)
OUTLET DRAIN
VALVE (6)
MAIN SHUT-OFF
VALVE (1)
INLET DRAIN
VALVE (2)
(If allowed by
local codes)
TO IRRIGATION
SYSTEM
DRAIN
DIRECTION OF FLOW
INLET
SHUT OFF
VALVE (3)
WARRANTY: ZURN WILKINS Valves are guaranteed against defects of material or workmanship when used for the services recom-
mended. If in any recommended service, a defect develops due to material or workmanship, and the device is returned, freight prepaid,
to ZURN WILKINS within 12 months from date of purchase, it will be repaired or replaced free of charge. ZURN WILKINS' liability shall
be limited to our agreement to repair or replace the valve only.
Proposition 65 Warning This product contains chemicals known to the State of California to cause cancer or birth defects
or other reproductive harm.
®
In accordance with U.S. Federal Safe Drinking Water Act Lead-Free requirements, as of January 4, 2014, this product can only be used in water sys-
tems considered non-potable. Please contact your local water utility for further requirements.