Install Instructions
2
Watts  Series  709  Double  Check  Valve 
may be installed in either a vertical or hori- 
zontal position.
Install valve in the line with arrow on valve 
body pointing in the direction of ow.
They  should  always  be  installed  in  an  
accessible  location  to  facilitate  testing  
and servicing.
Pipe lines should be thoroughly ushed to 
remove foreign material before installing 
the unit. A strainer should be installed as 
shown, ahead of backow preventers to 
prevent discs from unnecessary fouling.
CAUTION:  Do  not  install  with  strainer 
when backow preventer is used on sel-
dom-used  water  lines  which  are  called 
upon  during  emergencies,  such  as  re 
sprinkler lines, etc.
It is important that Series 709 be tested 
periodically  in  compliance  with  local 
codes, but at least once a year or more 
often, depending upon system conditions. 
(Send for IS-TK-7).
Indoor Installations
For indoor installations, it is important that 
the valve be easily accessible to facilitate 
testing and servicing.
Outdoor Installations
In area where freezing conditions do not 
occur, Series 709 can be installed outside of 
a building. The most satisfactory installation 
is above ground and should be installed in 
this manner whenever possible.
It is generally recommended that backow 
preventers never be placed in pits unless 
absolutely necessary and then only when 
approved by local codes. In such cases, 
a  modied  pit  installation  is  preferred 
or  an  insulated  above  ground  insulated 
enclosure.
Vertical
Horizontal
Watts 709S
2
1
⁄2" – 10"
Strainer
Indoor Installations
▼
▼
      mm  A   mm
 2
1
⁄2" – 3"  65-80  10"  300
  4  100  15"  450 
  6  150  15"  450 
  8  200  23"  680 
  10  250  25"  750
Clearance Required 
for Servicing
A
Now Available, 
WattsBox Insulated  
Enclosures. 
For more information, send for ES-WB  
or ES-WB-T.
Above Ground in Insulated Enclosure
For indoor installations, it is important that the valve be 
easily accessible to facilitate testing and servicing.
Outdoor Installations
Meter
Strainer
Watts 709S
2
1
⁄2" – 10" (65-250mm)
Basic Installation Instructions








