2
Installation Guidelines
Indoors
For indoor installation, make sure Series 919/LF919 is accessible
to facilitate testing and servicing. Do not install the assembly
in a concealed location. If the location is parallel and close to
the wall, make sure the test cocks are accessible and the drain
line can discharge water if required. An air gap and drain line
are piped from the relief valve connection, allowing evidence of
discharge to be visible and preventing the occurrence of water
damage. (Refer to ES-AG/EL/TC at watts.com.)
Air Gap
Strainer
Meter
12" Minimum
(refer to local codes)
Outdoor, Above Ground
For outdoor installations, install Series 919/LF919 where there
are no freezing conditions and above ground whenever possible.
Install the assembly in an accessible location to facilitate testing
and servicing. The installation must also allow for adequate
drainage from the air gap and the discharge line if needed.
WARNING
!
Do not allow the drain line to empty directly into a drainage
ditch, sewer system, or sump.
Do not install the assembly in any location where any part of the
unit could become submerged in standing water.
Now available, WattsBox Insulated Enclosures,
for more information, send for literature ES-WB.
Min. 12"
WattsBox Insulated Enclosure
For more information download ES-WB.
Parallel
For parallel installations, two or more small-sized assemblies
can be installed (when approved) to serve a large supply pipe
main. Use this type of installation in an application where
increased capacity beyond that provided by a single valve is
required. Additionally, this type of installation permits testing
and/or servicing of a single valve without shutting down the
complete line.
The number of units installed in parallel should be determined
by the engineer’s judgment, based on the operating conditions
of a specific application.
NOTICE
The total capacity of all the units installed in the application
should equal or exceed that required by the system.
A. Shutoff Valves: If you remove the shutoff valves from the
assembly, reassemble the shutoff valve with the test cock
mounted on the inlet side of the unit.
B. Check state and local codes to ensure the assembly is
installed in compliance with the codes, such as proper height
above the ground.
C. Recommended: Install a strainer ahead of the assembly to
protect the internal components from unnecessary fouling.
CAUTION
!
Do not install the assembly with a strainer in rarely used
water lines, such as a fire sprinkler system which is only
deployed during emergencies.
Start Up: Close the downstream shutoff. Open the upstream
slowly and fill the valve. When the valve is filled, open the
downstream shutoff slowly, and fill the water supply system.
This is necessary to avoid water hammer and/or shock
damage.
D. Vent the air gap and drain line from the relief valve in accor-
dance with code requirements. Terminate discharge approx-
imately 12" above the ground or through an air gap piped to
a floor drain.
WARNING
!
Do not allow the drain line to empty directly into a drainage
ditch, sewer system, or sump.
NOTICE
Relief Valve Discharge Rates. The air gap and drain line
terminating above a floor drain can accommodate any mod-
erate discharge or nuisance spitting through the relief valve.
However, to prevent water damage in the case of a cata-
strophic failure, design the floor drain size to accommodate
the increased discharge. (See table on typical flow rates as
sized by floor drain manufacturers, page 3.)
NOTICE
