2
RP-IS-709_709DCDA 2029
EDP# 0835235
© 2020 Watts
Vertical
Horizontal
Watts 709S/
LF709S
2
1
⁄
2
" – 10"
Strainer
For indoor installations, it is important that the valve be easily
accessible to facilitate testing and servicing.
Meter
Strainer
Watts 709S/LF709S
2
1
⁄
2
" – 10"
Installation Instructions
Series 709/LF709/709DCDA
Parallel Installations
Two or more Series 709 and LF709 devices may be piped in
parallel (where approved) to serve a large supply pipe main. This
type of installation is employed whenever it is vital to maintain a
continuous supply of water where interruptions for testing and
servicing would be unacceptable. It also has the advantage of
providing increased capacity where needed beyond that pro-
vided by a single valve.
For two valve installations the total capacity of the devices
should equal or exceed that required by the system. Capacity
table shows the size of the Series 709 and LF709 devices
required to meet a certain capacity. The quantity of devices used
in parallel should be determined by the engineers judgement
based on the operating conditions of a specific installation.
Above Ground Insulated Enclosure
WattsBox Insulated
Enclosure Available in
Aluminum or Fiberglass
For more information, reference ES-WB at
www.watts.com
NOTICE
Outdoor Installations
In area where freezing conditions do not occur, Series 709 and
LF709 can be installed outside of a building. The most satisfac-
tory installation is above ground and should be installed in this
manner whenever possible.
It is generally recommended that backflow preventers never be
placed in pits unless absolutely necessary and then only when
approved by local codes. In such cases, a modified pit installa-
tion is preferred or an above ground insulated enclosure.
Watts 709/LF709
2
1
⁄
2
" - 10"
Indoor Installations
For indoor installations, it is important that the valve be easily
accessible to facilitate testing and servicing.
Capacity Required for System
450 GPM
640 GPM
1000 GPM
2000 GPM
3000 GPM
5000 GPM
Two 2
1
⁄
2
"
Two 3"
Two 4"
Two 6"
Two 8"
Two 10"
Devices
Devices
Devices
Devices
Devices
Devices
Table shows total capacity provided with dual valve installations of
various sizes.
