2
Considerations
• Backflow preventers must be installed in high-visibility lo ca tions in
order to allow for immediate notice of telltale discharge or oth er
mal func tion. This location should also facilitate testing and ser vic ing
and protect against freezing and vandalism.
• Installation procedures must comply with all state and lo cal codes.
• Installing a backflow preventer in a pit or vault is not rec om mend-
ed. An air gap be low the relief port must be maintained so as to
avoid flood ing and sub mer sion of the assembly, which may lead
to a cross-connection. Watts recommends installations in doors or
above ground in an in su lat ed enclosure. (Refer to literature ES-WB
at watts.com.)
• A strainer should be installed ahead of the backflow pre ven ter to
protect the discs from unnecessary fouling.
CAUTION
!
Do not install a strainer ahead of the backflow pre ven ter on
seldom-used, emergency water lines such as fire sprinkler lines.
The strainer mesh could potentially become clogged with debris
present in the water and cause water blockage during an
emer gen cy.
• Normal discharge and nuisance spitting are ac com mo dat ed by
the use of a Watts air gap fitting and a fabricated indirect waste
line. Floor drains of the same size MUST be provided in case of
ex ces sive discharge.
• When installing an air gap, attach the air gap brackets directly onto
the flood sensor.
• When a Series 994 backflow preventer is installed for dead-end
ser vice applications, dis charge from the relief vent may occur
due to wa ter supply pressure fluc tu a tion during static no-flow
con di tions. A check valve may be re quired ahead of the
backflow preventer.
VALVE SIZE
TYPICAL FLOW RATES AS
SIZED BY FLOOR DRAIN
MANUFACTURERS
DRAIN SIZE
in.
gpm
in.
2
1
⁄
2
55
2
3
112
3
4
170
4
6, 8, 10
350
5
Installation Guidelines
Test Cock No. 2
Test Cock No. 3
Test Cock No. 4
Outlet
Shutoff
Check #2
Flood
Sensor
Sensing
Line
Check #1
Test Cock No. 1
Inlet Shutoff
Valve
• ASSEMBLY: If the backflow preventer is disassembled dur ing
in stal la tion, it MUST be reassembled in its proper order. The gate
valve with the test cock is to mounted on the inlet side of the
back flow pre ven ter. The test cock must be on the inlet side of the
wedge. Failure to reassemble correctly leads to possible wa ter
damage due to excessive discharge from the relief port/vent and
possible mal func tion of the backflow preventer.
• Before installation, thoroughly flush the pipeline to re move any
for eign matter.
• START UP at Initial Installations and After Servicing: The down-
stream shutoff should be closed. Slowly open the upstream shutoff
and allow the backflow preventer to fill slowly. Bleed air at each
test cock. When the backflow preventer is filled, slowly open
the down stream shut off and fill the water supply system. This is
nec es sary to avoid water hammer or shock damage.
NOTICE
Assembly body should not be painted.
The flange gasket bolts for the gate valves should be re tight ened
during in stal la tion as the bolts may have loos ened due to storage
and ship ping
.
