Watts 909QT-S, 909QT Basic Installation Instructions

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. Backow 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 backow 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 backow
preventer to protect all internal components from un­necessary fouling.

CAUTION - Do not install a strainer ahead of the backow

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 backow 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
backow preventer. *Please see “Troubleshooting”,
page 7, prior to installation.

6. The 909 Series backow 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 specic 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 backow preventer to
ll slowly. Bleed air at each test cock. When backow
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 backow preventer must be tested
by a certied 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 backow.

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 backow preventers never
be placed in pits unless absolutely necessary, and then only,
when approved by local codes. In such cases, a modied 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 specic 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

Test Procedure for Reduced Pressure Assembly

A. All needle valves must be closed on test kit.
B. Open test cock No. 4 and ush test cocks Nos. 1, 2 and 3 on reduced pressure

assembly then close test cock No. 4.
C. Attach hoses as shown. Bleed air from kit, close No. 2 shutoff.

Bleed Valve A

High

(red)

Low

(blue)

Bleed Valve B

Bypass
(yellow)

Test No. 1 - Check Valve No.2

Purpose: To test check valve No. 2 for tightness against
reverse ow.

Requirements: Valve must be tight against reverse ow under
all pressure differentials.

Step 1 Slowly open the needle valve “A” high side (red) and “C”
bypass (yellow). Keep the “B” low (blue) closed.

Step 2 Open test cock No. 4.
Step 3 Indicated pressure differential will decrease slightly. If

pressure differential continues to decrease (until the vent
opens) the No. 2 check valve is reported as “leaking”.

Test No. 2 - Shutoff Valve No. 2

Purpose: To test shutoff valve No. 2 for tightness.
Step 1 After passing Test No. 1, continue to test No. 2 by

closing test cock No. 2.
Step 2 The indicated pressure differential will decrease slightly.

If pressure differential continues to decrease
(approaching “zero”), the No. 2 shutoff valve is reported
to be “leaking”. Note: A leaking No. 2 shutoff will give a
false reading in tests No. 3 and 4.

Test No. 3 - To Test No. 1 Check Valve

Purpose: To test check valve No. 1 for tightness.
Requirements: Valve must be tight against reverse ow under

all pressure differentials.
Step 1 Close needle valve “A” high side (red) and open test

cock No. 2
Step 2 Close test cock No. 4. Disconnect bypass hose (yellow)

at test cock No. 4.

No. 2 shutoff

909QT shown

Step 3 Open needle valve “B” low (blue) and “C” bypass

(yellow), bleeding to atmosphere, then closing needle
valve “B” (blue) restores the system to a normal
static condition.

Step 4 Observe the pressure differential gauge. If there is a
decrease in the indicated value, the No. 1 check valve is
reported as “leaking”.

Test No. 4 - Pressure Differential Relief Valve

Purpose: To test operation of pressure differential
relief valve.

Requirements: The pressure differential relief valve must
operate to maintain the “zone” between the two check valves
at least 2psi less than the supply pressure.

Step 1 Close needle valve “C” bypass (yellow).
Step 2 Open needle valve “A” high side (red).
Step 3 Open needle valve “B” low (blue) very slowly until the

differential gauge needle starts to drop.
Step 4 Hold the valve at this position and observe the gauge

reading at the moment the rst discharge is noted from
the relief valve. Record this as the opening differential
pressure of the relief valve. Note: it is important that the
differential gauge needle drops slowly.

Step 5 Close test cocks Nos. 2 and 3. Remove hose from test
cocks Nos. 2 and 3.

Step 6 Use bypass hose (yellow) to relieve pressure from test
kit by opening needle valve “A”, “B” and “C” and bleed
valves “A” and “B”.

Step 7 Remove all test equipment and open No. 2 shutoff valve
of the device.

CAUTION: To prevent freezing, hold Test Kit vertically to drain differential gauge and hoses prior to placing in case.
For additional testing information, send for IS-TK-DP/DL, IS-TK-9A, IS-TK-99E or IS-TK-99D.

4

Servicing First and Second Check Valves 3/4" to 2" (20 to 50mm)

Note:

No special tools

required to service

Series 909

Relief Valve
Service Parts Kit

First Check

Cover

Service Parts Kit

Cover
O-ring

Spring

Disc

Assembly

Body

1. Remove the four screws holding
the rst check valve cover.

Second Check
Service Parts Kit

2. Lift off the rst check valve cover. The

check valve inside will come out with the
cover and is attached with a bayonet type
locking arrangement.

3. Holding the check valve module in both hands,

rotate the assembly quarter turn. This will disengage
the disc assembly, spring and seat cover into

First Check

Seat

Seat

O-ring

individual components.

4. The disc assembly may be cleaned and reassembled, or depending upon its

condition, it may be discarded and replaced with a new assembly from the
service kit. O-rings should be cleaned or replaced as necessary and lightly
greased with the FDA approved silicon grease which is also furnished with
the service kit.

Note: The springs and covers of the

first and second check valves are not

interchangeable. The heavier spring loaded
module should be in the first check and the

lighter in the second check module.

5. Reassemble the check valve module in the reverse order. Service is identical

for both the rst and second check valves.

For further details contact your local technical sales representative, see back page.

Second Check

3

/4" to 2" Replacement Parts

When ordering, specify Ordering Code Number, Kit Number† and Valve Size

First Check Kits

Order No. Kit. No. Sizes in. mm

0887120 RK 909 CK1
0887133 RK 909 CK1 1
0887122 RK 909 CK1SS*
0887135 RK 909 CK1SS* 1

Kit includes: Disc assembly, Spring, Seat, Seat o-ring, Cover o-ring
and lubricant. *Stainless Steel Seat.

Second Check Kits

0887121 RK 909 CK2
0887134 RK 909 CK2 1
0887123 RK 909 CK2SS*
0887136 RK 909 CK2SS* 1

Kit includes: Disc assembly, Spring, Seat, Seat o-ring, Cover o-ring
and lubricant. *Stainless Steel Seat.

Rubber Parts for Both Checks

0887129 RK 909 RC3
0887142 RK 909 RC3 1
0887310 RK 909 RC3 HW
0887311 RK 909 RC3 HW 1

Kit includes: Check discs, Seat o-rings, Cover o-rings and lubricant.
HW model has bronze disc. †Note: 11⁄4" – 2" (32-50mm) 909/909M1

share a common kit.

3

⁄4 – 1 20-25

1

⁄4 – 2 32-50

3

⁄4 – 1 20-25

1

⁄4 – 2 32-50

3

⁄4 – 1 20-25

1

⁄4 – 2 32-50

3

⁄4 – 1 20-25

1

⁄4 – 2 32-50

3

⁄4 – 1 20-25

1

⁄4 – 2 32-50

3

⁄4 – 1 20-25

1

⁄4 – 2 32-50

For other repair kits and parts send for PL-RP-BPD.

Complete Rubber Parts

Order No. Kit No. Size in. mm

0887130 RK 909 RT
0887144 RK 909 RT 1

Kit includes: Check discs, Seat o-rings, RV diaphragm, RV o-rings,
Piston o-rings, Cover o-rings and lubricant.

Seat Kits for One Check

0887124 RK 909 S
0887139 RK 909 S 1
0887125 RK 909 S-SS*
0887140 RK 909 S-SS* 1

Kit includes: Seat, Seat o-ring and lubricant. *Stainless Steel Seat.

Cover Kits

0887127 RK 909 C1
0887128 RK 909 C2
0887132 RK 909 VC
0887137 RK 909 C4 1
0887143 RK 909 VC 1

Kit includes: Cover, Cover o-ring and lubricant.

3

⁄4 – 1 20-25

1

⁄4 – 2 32-50

3

⁄4 – 1 20-25

1

⁄4 – 2 32-50

3

⁄4 – 1 20-25

1

⁄4 – 2 32-50

3

⁄4 – 1 20-25

3

⁄4 – 1 20-25

3

⁄4 – 1 20-25

1

⁄4 – 2 32-50

1

⁄4 – 2 32-50

5

Servicing the Relief Valve 3/4" to 2"

1. Remove the four bolts that hold the relief valve cover
in place.

2. Remove the cover. The stainless steel adapter, with o-ring
attached will be free to be removed simultaneous with the
removal of the cover. Pull out the relief valve assembly.
Note: the spring tension in the relief valve assembly is
contained in the design of the relief valve; therefore, the
relief can be removed in a one-piece spool-type assembly.

3. The relief valve seat and disc may be cleaned without
disassembly of the relief valve assembly. If it is determined
that the relief valve diaphragm and/or disc should be
replaced, the relief valve module can be readily
disassembled without the use of special tools.

Repair Kits

†

Relief Valve Kits

Order Code No. Kit No. Size in. mm

0887126 RK 909 VT
0887138 RK 909 VT 1

Kit includes: Relief valve assembly, Seat, Seat o-ring, Cover o-ring
and lubricant.

Rubber Parts for Relief Valve

0887131 RK 909 RV
0887141 RK 909 RV 1

Kit includes: Diaphragm, Disc assembly, Seat o-ring, RV o-ring,
Piston o-rings, Cover o-ring and lubricant.

Seat Kits for Relief Valve

0887372 RK 909 SV
0887371 RK 909 SV 1

Kit includes: Seat, Seat o-ring, Piston o-ring and lubricant.

†

Note: 11⁄4" - 2" (32-50mm) 909/909M1 share a common kit.

3

⁄4 – 1 20-25

1

⁄4 – 2 32-50

3

⁄4 – 1 20-25

1

⁄4 – 2 32-50

3

⁄4 – 1 20-25

1

⁄4 – 2 32-50

Piston

Size 3⁄4” – 1”

Piston
O-ring

Relief Valve
Assembly

Stem

Cover

Diaphragm

Disc Assembly

RV O-Ring

Seat
O-ring

Size 11⁄4" – 2" (32-50mm)

Cover

Piston

Diaphragm

For further details contact your local technical sales
representative, see back page.

(2) Piston
O-rings

Disc Assembly

Stem

(2) RV O-Rings

Seat

Body

Relief Valve
Assembly

Seat
O-ring

Seat

To Prevent Shaft Damage Assemble As Shown:

Caution: If cover will not press against body, assembly is crooked and tightening bolts will bend shaft. Do not force the cover into
place as damage may result from misalignment.

Figure 1

Figure 2

Figure 3

Figure 1:

To assemble the Relief Valve Assembly
have a screwdriver ready.

6

Figure 2:

Depress the Relief Valve Assembly,
carefully guiding it against the two pound
spring load. When properly aligned, the
piston is in the cylinder bore. Insert the
screwdriver as shown.

Figure 3:

The Relief Valve Assembly is held
encapsulated by the screwdriver. You
should now have both hands free to
bolt down the cover. Insert and snug
two bolts 180° apart to hold the cover.
Finish inserting the remaining bolts and
snug up evenly, alternating until secure.
Remove the screwdriver.

Troubleshooting Guide - Backflow Preventers

Problem Cause Solution

A. Valve spits periodically from the vent.

A.1 Fluctuating supply pressure.

A.2 Fluctuating downstream pressure.

B. Valve drips continually from the vent

B.1 Fouled rst check.

B.2 Damaged or fouled relief valve seat.

B.3 Relief valve piston O-ring not free to move

due to pipe scale, dirt or build up of
mineral deposits.

B.4 Excessive backpressure, freezing or water
hammer has distorted the second check.

B.5 Electrolysis of relief valve seat or rst
check seats.

B.6 Valve improperly reassembled.

C. Valve exhibits high pressure drop.

C.1 Fouled strainer.

C.2 Valve too small for ows encountered.

D. No water ow downstream of valve.

D. Valve installed backwards.

E. Valve does not test properly.

E.1 Follow manufacturer’s test procedure

E.2 Leaky downstream gate valve.

F. Valve quickly and repeatedly fouls following
servicing.

F. Debris in pipe line is too ne to be trapped

by strainer.

G. Winterization of backow preventers.

A.1 Install a soft seated check valve immediately

upstream of the device. (Watts 3⁄4" - 2" (20-50mm)
No. 601 bronze valve.)

A.2 Install a soft seated check valve downstream of
the device close as possible to the shutoff valve.
(Watts 3⁄4" - 2" (20-50mm) No. 601 bronze valve.)

B.1 Flush valve. If ushing does not resolve problem,
disassemble valve and clean or replace the
rst check.

B.2 Clean or replace the relief valve seat.

B.3 Clean, grease or replace the piston O-ring.

B.4 Eliminate source of excessive backpressure or

water hammer in the system downstream of the
device. Use Watts No. 601 to dampen out back
pressure and No. 15 to eliminate water hammer.
Replace defective second check assembly. In
case of freezing; thaw, disassemble and inspect
internal components. Replace as necessary.

B.5 Replace relief valve seat or inlet cover. Install
dielectric unions (Watts Series 3001 through 3006).
Electrically ground the piping system and/or
electrically isolate the device with plastic pipe im­ mediately upstream and downstream of the device.

B.6 If valve is disassembled during installation, caution
must be exercised to install check springs in their
proper location.

C.1 Clean strainer element or replace.

C.2 Install proper size device based upon

ow requirements.

D. Install valve in accordance with ow
direction arrow.

E.1, E.2 Clean or replace gate valve with full port ball
valves or resilient wedge shutoff valves.

F. Install ner mesh strainer element in the strainer.

G. Electric heat-tape wrap closely together around

valve body. Build a small shelter around the valve
with a large light bulb installed and left on
at all times.

If supply line is not used during the winter, re­ moval of the complete body is the best. This
would create an air gap to eliminate any
possible backow.

7

For additional information, visit our web site at: www.watts.com

A Watts Water Technologies Company

RP/IS-909S 1111 EDP# 0834246 © 2011 Watts

USA: No. Andover, MA • Tel. [phone] • Fax: [phone] • www.watts.com

Canada: Burlington, ON • Tel. [phone] • Fax: [phone] • www.wattscanada.ca