Watts LF909 User Manual
RP/IS-909/909RPDA
Installation, Maintenance, & Repair
Series 909, LF909, 909RPDA, LF909RPDA
Reduced Pressure Zone Assemblies
Reduced Pressure Detector Assemblies
Sizes: 21⁄2" – 10" (65 – 250mm)
!
WARNING
Read this Manual BEFORE using this equipment.
Failure to read and follow all safety and use information
can result in death, serious personal injury, property
damage, or damage to the equipment.
Keep this Manual for future reference.
Watts 909 OSY shown
Designed for inline servicing
Local building or plumbing codes may require modifications to
the information provided. You are required to consult the local
building and plumbing codes prior to installation. If this information is not consistent with local building or plumbing codes, the
local codes should be followed.
Need for Periodic Inspection/Maintenance: This product
must be tested periodically in compliance with local codes, but
at least once per year or more as service conditions warrant.
Corrosive water conditions, and/or unauthorized adjustments
or repair could render the product ineffective for the service intended. Regular checking and cleaning of the product’s internal
components helps assure maximum life and proper product
function.
IMPORTANT: Inquire with governing authorities for local installa-
tion requirements.
NOTICE
For Australia and New Zealand, line strainers should be installed
between the upstream shutoff valve and the inlet of the backflow preventer.
Its important that this device be tested periodically in compliance
with local codes, but at least once per year or more as service conditions warrant. If installed on a fire sprinkler system, all mechanical
checks, such as alarm checks and backflow preventers, should be
flow tested and inspected internally in accordance with NFPA 13
and NFPA 25.
Testing
For field testing procedure, send for IS-TK-DL,
IS-TK-9A, IS-TK-99E and IS-TK-99D.
For repair kits and service parts, reference PL-RP-BPD at
www.watts.com
For technical assistance, contact your local Watts
representative.
Basic Installation Instructions
NOTICE
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 stor age
and ship ping.
High Capacity Relief Series:
Location and Installation Considerations
1. Backflow preventers must be installed in high-visibility locations
in order to allow for immediate notice of telltale discharge or
other malfunction. This location should also facilitate testing and
ser vic ing, and protect against freezing and vandalism.
2. Installing a backflow preventer in a pit or vault is not rec ommend ed. However, if this becomes necessary, Watts highly recom mends that a licensed journeyman tradesperson, who is recognized by the authority having jurisdiction, be consulted to
ensure that all local codes and required safety provisions are
met. An air gap below the relief port must be maintained so as
to avoid flooding and submersion of the assembly, which may
lead to a cross connection. *Please refer to Figure No. 1 for further information.
3. A strainer should be installed ahead of the backflow preventer to
protect all internal components from unnecessary fouling.
!
CAUTION
Do not install a strainer ahead of the backflow preventer on seldomused, emergency water lines (i.e. 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.
4. Normal discharge and nuisance spitting are accommodated 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
excessive discharge. *Please refer to Figure No. 1 and Figure
No. 2 for further in for ma tion.
5. When a 909/LF909 Series backflow preventer is installed for
dead-end service applications. (i.e. boiler feed lines, cooling
tower makeup or other equip ment with periodic flow requirements), discharge from the relief vent may occur due to water
supply pressure fluctuation during static no-flow con di tions. A
check valve may be required ahead of the backflow preventer.
*Please see “Troubleshooting”, Page 7, prior to installation.
Basic Installation Instructions
Series 909/LF909
Sizes: 21⁄2" – 10" (65 – 250mm)
6. The relief valve module on 21⁄2" – 10" (65 – 250mm) 909/LF909
Series assemblies may be turned to discharge to the opposite
side. To do so, unbolt the relief valve and turn the relief valve discharge port to the opposite side. Mount the high pressure hose
on the op po site. This should be done by a licensed journeyman
tradesperson, who is rec og nized by the authority having jurisdiction and only when space is critical for testing or repair.
7. ASSEMBLY: If the backflow preventer is disassembled during
installation, it MUST be reassembled in its proper order. The gate
valve with the test cock is to be mounted on the inlet side of the
backflow preventer. The test cock must be on the inlet side of
the wedge. Please see above. Failure to reassemble correctly will
result in possible water damage due to excessive discharge from
the relief port/vent and possible malfunction of the backflow preventer.
8. Installation procedures must comply with all state and local
codes and must be completed by a licensed journeyman tradesperson who is recognized by the authority having ju ris dic tion.
9. Prior to installation, thoroughly flush all pipe lines to remove any
foreign matter.
10. START UP at Initial Installation and After Servicing: The downstream shutoff should be closed. Slowly open upstream shutoff
and allow the backflow preventer to fill slowly. Bleed air at each
test cock. When backflow preventer is filled, slowly open the
down stream shutoff and fill the water supply system. This is necessary to avoid dislodging O-rings or causing damage to internal
com po nents.
11. TEST: The 909/LF909 Series backflow preventer may be tested
by a certified tester at the time of installation in order to ascertain
that the assembly is in full working order and may be relied upon
to protect the safe drinking water as per applicable standard.
Watts No. 909/LF909
1
2
⁄2" – 10" (65 – 250mm)
Inlet
Shutoff
Valve
First
Check
Second
Check
Relief Valve
Second
Shutoff
Valve
Figure 1
Series 909/LF909
Relief Valve Dis charge Rates
175
150
125
21⁄2” – 3” 909
100
75
50
ZONE PRESSURE (PSIG)
25
0
0 100 200 300 400 500 600 700 800 900
FLOW RATE (GPM)
4” – 10” 909
Figure 2
VALVE SIZE TYPICAL FLOW RATES AS SIZED BY
FLOOR DRAIN MANUFACTURERS
in. mm in. mm
1
⁄2” 65 55 gpm 2 50
2
DRAIN SIZE
3” 80 112 gpm 3 65
4” 100 170 gpm 4 100
6”, 8”, 10” 150,200,250 350 gpm 5 125
2
Installation
A. Series 909/LF909 should be installed in a horizontal and upright
position. This positions the relief valve below the first check
valve, enabling the zone to drain through the relief valve outlet.
The shutoff valve with the test cock is to be mounted on the inlet
side of the backflow preventer. The test cock is on the inlet side
of the shutoff valve.
B. The 909/LF909 should always be installed in an accessible loca-
tion to facilitate testing and servicing. Check the state and local
codes to insure that the backflow preventer is installed in compliance, such as the proper height above the ground.
C. Water discharge from the relief valve should be vented in accor-
dance with code requirements. The relief valve should never be
solidly piped into a drainage ditch, sewer or sump. The discharge should be funneled through a Watts air gap fitting piped
to a floor drain.
D. Watts recommends a strainer be installed ahead of Watts 909
Series assemblies to protect the discs from unnecessary fouling.
E. Backflow preventers should never be placed in pits unless abso-
lutely necessary and then only when and as approved by local
codes. Consult your local or state plumbing or health inspector.
Watts recommends installation indoors or above ground in an
insulated enclosure.
Start Up
F. The downstream shutoff should be closed. Open upstream
slowly, fill the valve and bleed the air through Test cock 2, 3 and
4. When valve is filled, open the downstream shutoff slowly and
fill the water supply system. This is necessary to avoid water
hammer or shock damage.
G. The installation of a Watts air gap with the drain line terminating
above a floor drain will handle any normal discharge or nuisance
spitting through the relief valve. However, floor drain size may
need to be designed to prevent water damage caused by a catastrophic failure condition. Do not reduce the size of the drain
line from the air gap fitting.
H. 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 assemblies used in parallel should be determined by
the engineer’s judgement based on the operating conditions of a
specific installation.
Indoors
Watts 909S/LF909S FDA
1
2
⁄2” - 10” (65 - 250mm)
Main
Meter Strainer
Air
Gap
12” (300mm)
Above Ground
Min. 12” (300mm)
Now available, WattsBox Insulated Enclosures, for more information, send for ES-WB.
Parallel
Watts 909/LF909
21⁄2" – 10" (65 – 250mm)
Air Gap
support
Strainer
TABLE ONE - CAPACITY REQUIRED FOR SYSTEM
50 GPM 100 GPM 150 GPM 200 GPM 250 GPM 350 GPM
Two 3⁄4" Two 1" Two 11⁄4" Two 11⁄2" Two 11⁄2" Two 2"
Devices Devices Devices Devices Devices Devices
450 GPM 640 GPM 1000 GPM 2000 GPM 3000 GPM 5000 GPM
Two 21⁄2" 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.
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