Figure 2
TYPICAL FLOW RATES
VALVE
AS SIZED BY FLOOR
DRAIN
SIZE
DRAIN MANUFACTURERS
SIZE
in.
mm
in.
mm
2
1
⁄
2
"
65
55 gpm
2
50
3"
80
112 gpm
3
65
4"
100
170 gpm
4
100
6", 8", 10" 150,200,250
350 gpm
5
125
Basic Installation Instructions
Series 909
Sizes: 2
1
⁄
2
" – 10" (65 – 250mm) 909
High Capacity Relief Series:
Location and Installation Considerations
6. The relief valve module on 2
1
⁄
2
" – 10" (65 – 250mm) 909 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
opposite. This should be done by a licensed journeyman trades-
person, who is recognized 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 cor-
rectly will result in possible water damage due to excessive dis-
charge 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 juris-
diction.
Please see Page 3 for specific installation procedures.
9. Prior to installation, thoroughly flush all pipe lines to remove any
foreign matter.
10.
START UP at Initial Installation and After Servicing:
The down-
stream 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
downstream shutoff and fill the water supply system. This is nec-
essary to avoid dislodging O-rings or causing damage to internal
components.
11.
TEST:
The 909 Series backflow preventer may be test-
ed 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.
Figure 1
Series 909 RELIEF VALVE DISCHARGE RATES
ZONE PRESSURE (PSIG)
FLOW RATE (GPM)
Installation Note:
The flange gasket bolts for the
gate valves should be retight-
ened during installation as the
bolts may have loosened due
to storage and shipping.
Relief Valve
First
Check
Second
Check
Second
Shutoff
Valve
Inlet
Shutoff
Valve
2
1
⁄
2
" – 3" 909
4" – 10" 909
175
150
125
100
75
50
25
0
0
100 200
300
400
500
600
700
800 900
Watts No. 909
2
1
⁄
2
" – 10" (65 – 250mm)
2
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 servic-
ing, and protect against freezing and vandalism.
2. Installing a backflow preventer in a pit or vault is not recom-
mended. However, if this becomes necessary, Watts highly rec-
ommends that a licensed journeyman tradesperson, who is rec-
ognized 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 fur-
ther 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 seldom-used, 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-
gency.
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 information.
5. When a 909 Series backflow preventer is installed for dead-end
service applications. (i.e. boiler feed lines, cooling tower makeup
or other equipment with periodic flow requirements), discharge
from the relief vent may occur due to water supply pressure fluc-
tuation during static no-flow conditions. A check valve may be
required ahead of the backflow preventer. *Please see
“Troubleshooting”, Page 7,
prior to installation.
