Indoors -
Figure 1
Check local codes for installation requirements. Pipe lines should
be thoroughly flushed to remove foreign material before installing
the unit. A strainer should be installed as shown, ahead of backflow
preventer to prevent disc from unnecessary fouling. Install valve in
the line with arrow on valve body pointing in the direction of flow.
For indoor installations, it is important that the valve be easily
accessible to facilitate testing and servicing. Do not install in a
concealed location.
CAUTION:
Do not install with strainer when backflow preventer is used on
seldom-used water lines which are called upon during emer-
gencies, such as fire sprinkler lines, etc.
It is important that Series 719 and LF719 be tested periodically
in compliance with local codes but at least once a year or more
often depending upon system conditions. Regular inspection,
testing and cleaning assures maximum life and proper product
function.
NOTE:
Fire Protection System Installations
The National Fire Protection Agency (NFPA) Guidelines require
a confirming flow test to be conducted whenever a “main line”
valve such as the shutoff valves or a backflow assembly have
been operated. Certified testers of backflow assemblies must
conduct this test. The trim valves of the confirming flow test
must be closed during the test. When the test is completed,
the trim valves must be returned to a fully open position.
Outside -
Figure 2
Parallel -
Figure 3
Where approved by code, Watts recommends a custom engi-
neered Watts PVS Series water supply valve station consisting of
two or more 719 and LF719 Series valves piped in parallel to serve
a larger supply main. This type of installation is employed whenever
it is required to maintain water flow to a facility. Typical applications
include hospitals, multi-family dwellings, malls and other similar
applications.
A properly designed Watts PVS valve station provides redundant
flow paths, a continuous supply of adequate water, testing and
servicing of an individual valve without supply interruption, and
long service life.
The size, quantities and design of parallel valve installations should
be exactly in accordance with the engineer’s judgment and the
published Best Practice Guide of Watts Regulator wherever pos-
sible. For a copy of the Watts Best Practice Guide, call Watts at
1-800-617-3274.
2
Installation Instructions
Series 719 and LF719 Double Check Valve Assemblies
719AQT
Meter Box Installation
First Shutoff
Valve
719QT-S Vertical flow-up installation
Strainer
Min. 12"
Fiberglass WattsBox
Now Available, WattsBox Insulated Enclosures.
For more information, send for ES-WB or ES-WB-T.
Figure 2
719QT-S
First
Shutoff Valve
Figure 3
First
Shutoff Valve
719QT-S
Strainer
Figure 1
