Series 909
Reduced Pressure
Zone Backflow Preventers
RP/IS-909S
Sizes:
3
/4" – 2" (20 – 50mm)
• Installation
• Service
• Repair Kits
• Maintenance
No. 909QT-S 11⁄2" shown
For field testing procedure, send for IS-TK-DP/DL,
IS-TK-9A, IS-TK-99E and IS-TK-99D.
For troubleshooting guide, send for S-TSG.
For other repair kits and service parts, send for
PL-RP-BPD.
For technical assistance, contact your local Watts
representative on back page.
IMPORTANT: Inquire with governing authorities for local installation requirements.
NOTE: 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.
Limited Warranty: Watts Regulator Co. (the “Company”) warrants each product to be free from defects in material and workmanship under normal usage for a period of one year from the date of
original shipment. In the event of such defects within the warranty period, the Company will, at its option, replace or recondition the product without charge.
THE WARRANTY SET FORTH HEREIN IS GIVEN EXPRESSLY AND IS THE ONLY WARRANTY GIVEN BY THE COMPANY WITH RESPECT TO THE PRODUCT. THE COMPANY MAKES NO OTHER
WARRANTIES, EXPRESS OR IMPLIED. THE COMPANY HEREBY SPECIFICALLY DISCLAIMS ALL OTHER WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
The remedy described in the first paragraph of this warranty shall constitute the sole and exclusive remedy for breach of warranty, and the Company shall not be responsible for any incidental,
special or consequential damages, including without limitation, lost profits or the cost of repairing or replacing other property which is damaged if this product does not work properly, other costs
resulting from labor charges, delays, vandalism, negligence, fouling caused by foreign material, damage from adverse water conditions, chemical, or any other circumstances over which the Company
has no control. This warranty shall be invalidated by any abuse, misuse, misapplication, improper installation or improper maintenance or alteration of the product.
Some States do not allow limitations on how long an implied warranty lasts, and some States do not allow the exclusion or limitation of incidental or consequential damages. Therefore the above
limitations may not apply to you. This Limited Warranty gives you specific legal rights, and you may have other rights that vary from State to State. You should consult applicable state laws to
determine your rights. SO FAR AS IS CONSISTENT WITH APPLICABLE STATE LAW, ANY IMPLIED WARRANTIES THAT MAY NOT BE DISCLAIMED, INCLUDING THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE LIMITED IN DURATION TO ONE YEAR FROM THE DATE OF ORIGINAL SHIPMENT.
Basic Installation Instructions
First
Check
3
Watts
⁄4" – 2" (20-50mm) 909QT High Capacity Relief Series:
Location and Installation Considerations
909QT
Second
Check
Relief
Valve
1. Backow 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 servicing, and protect against
freezing and vandalism.
2. Installing a backow preventer in a pit or vault is not
recommended as ooding of the pit will cause a crossconnection. 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, ooding and submersion of the assembly, which may lead to a crossconnection.
3. A strainer should be installed ahead of the backow
preventer to protect all internal components from unnecessary fouling.
CAUTION - Do not install a strainer ahead of the backow
preventer on seldom-used, emergency water lines (i.e.
re sprinkler lines). The strainer mesh could potentially become clogged with debris present in the water and cause
water blockage during an emergency.
4. Normal discharge and nuisance spitting are accommodated by the use of a Watts air gap tting and a fabricated
indirect waste line. Floor drains of the same size MUST
be provided in case of excessive discharge.
5. When a 909 Series backow preventer is installed
for dead-end service applications (i.e. boiler feed
lines, cooling tower makeup or other equipment
with periodic ow requirements), discharge from
the relief vent may occur due to water supply
pressure uctuation during static no-ow conditions. A check valve may be required ahead of the
backow preventer. *Please see “Troubleshooting”,
page 7, prior to installation.
6. The 909 Series backow preventer is designed so that
the critical level of the relief valve is positioned below the
rst check. This unique feature allows the valve to be
installed either vertically or horizontally.
7. Installation procedures must comply with all state
and local codes. *Please see page 3 for specic in-
stallation procedures.
8. Prior to installation, thoroughly ush all pipe lines to
remove any foreign matter.
9. Start up at Initial Installations and After Servicing: The
downstream shutoff should be closed. Slowly open
upstream shutoff and allow the backow preventer to
ll slowly. Bleed air at each test cock. When backow
preventer is lled, slowly open the downstream shutoff
and ll the water supply system. This is necessary to
avoid dislodging O-rings or causing damage to internal
components.
10. Test: The 909 Series backow preventer must be tested
by a certied 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 standards.
Repair Parts: Use only original equipment, manufactured parts
to protect the validated warranty.
2
How It Operates
The unique relief valve construction
incorporates two channels: one for air,
one for water. When the relief valve
opens, as in the accompanying airin/water-out diagram, the right hand
channel admits air to the top of the
reduced pressure zone, relieving the
zone vacuum. The channel on the left
then drains the zone to atmosphere.
Therefore, if both check valves foul,
and simultaneous negative supply and
positive backpressure develops, the
relief valve uses the air-in/water-out
principle to stop potential backow.
Reduced
Pressure
Zone
Water Out
Air In
Installation Indoors
ASSE approved for vertical installation
3
⁄4" – 2" flow up and down
For indoor installations, it is important that the
valve be easily accessible to facilitate testing and
servicing. Series 909 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
First
Check
Valve
connection as shown, where evidence of discharge
will be clearly visible and so that water damage
will not occur. Therefore, never install in concealed
locations.
Flow
Note: Test cock must be located on the rst or inlet
shutoff valve.
*For Air Gap information contact your technical
sales representative or refer to ES-AG/EL.
Installation - Outside Building Above Ground
In an area where freezing conditions do not occur, Series 909
can be installed outside of a building. The most satisfactory
installation is above ground and should be installed in this
manner whenever possible.
In an area where freezing conditions can occur, Series 909
should be installed above ground in an insulated enclosure.
Series 909 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. Series 909 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.
It is generally recommended that backow preventers never
be placed in pits unless absolutely necessary, and then only,
when approved by local codes. In such cases, a modied pit
installation is preferred.
Now available, WattsBox Insulated Enclosures,
for more information, send for ES-WB or ES-WB-T.
909QT-S
Air In
Water
Out
Relief Valve
Below First
Check Valve
Main
▼
Air*
Gap
Vertical Installation - Upward Flow
FIBERGLASS WattsBox
Min. 12"
Min.
4
▼
1
⁄2"
▼
Installation - Parallel 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 engineer’s judgement based on the operating conditions of
a specic installation.
Table One - Capacity Required for System
50 gpm 100 gpm 150 gpm 200 gpm 250 gpm 350 gpm
3
Two
⁄4" Two 1" Two 11⁄4" Two 11⁄2" Two 11⁄2" Two 2"
Devices Devices Devices Devices Devices Devices
Table shows total capacity provided with dual valve installations
of various sizes.
909QT-S
Air Gap
909QT-S
(Drawings not to scale)
3
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