Watts LF909 Pequeno Serie Manual De Instalación página 3

Indoors
ASSE Approved for vertical installation flow up and
down
For indoor installations, the valve must be easily
accessible to facilitate testing and servicing. The
assembly may be installed either vertically or horizontally.
If it is located in a line close to wall, be sure the test
cocks are easily accessible. A drain line and air gap
should be piped from the relief valve connection as
shown, where evidence of discharge is clearly visible and
so that water damage can be limited. Therefore, never
install the assembly in concealed locations.
NOTICE
Test cock must be located on the first or inlet shutoff
valve.
For more information on the air gap, download ES-AG/
EL/TC at watts.com.
Outside Building Above Ground
In an area where freezing conditions do not occur, the assembly
can be installed outside of a building. The most satisfactory
installation is above ground; install in this manner whenever
possible.
In an area where freezing conditions can occur, the assembly
should be installed above ground in an insulated enclosure.
The assembly may be installed in a vertical or horizontal line and
in an accessible location to facilitate testing and servicing. A
discharge line should be piped from the air gap at the relief valve
connection making sure there is adequate drainage. Never pipe
the discharge line directly into a drainage ditch, sewer, or sump.
The assembly should never be installed where any part of the
unit could become submerged in standing water. Consideration
should be given to the installation of external support structure
as applicable.
In general, the installation of backflow preventers into pits is not
recommended. This type of installation should occur only when
absolutely necessary and then only when approved by local
codes. In such cases, a modified pit installation is preferred.
Parallel
NOTICE
Consult local codes for approval.
Two or more smaller size valves can be piped in parallel (when
approved) to serve a larger supply pipe main. This type of
installation is employed where increased capacity is needed
beyond that provided by a single valve and permits testing
or servicing of an individual valve without shutting down the
complete line.
The number of valves used in parallel should be determined by
the judgment of the compliance engineer based on the operating
conditions of a specific installation.
The following table shows the total capacity provided with dual
valve installations of various sizes.
CAPACITY REQUIRED FOR SYSTEM
50 gpm 100 gpm 150 gpm
Two ⁄ " Two 1" Two 1
3
4
Devices Devices Devices
200 gpm 250 gpm
⁄ " Two 1 ⁄ " Two 1 ⁄ "
1 1 1
4 2 2
Devices Devices
First
Check
Valve
Flow
LF909-QT-S-FS
350 gpm
Two 2"
Devices
Air In
Water
Out
Relief Valve
Below First Check
Valve
Main
Vertical Installation - Upward Flow
Min.
12"
WattsBox Insulated Enclosures
For more information, download ES-WB.
LF909-S-FS
Air Gap
(Drawings not to scale)
LF909-QT-S
Min.
4 ⁄ "
1
2
Air
Gap
3