Watts M1115-74 User Manual

Mu s t a n g se r i e s

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X

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Y/FC

(AOS)

P/L

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CLOSES VALVE

OPENS VALVE

FLOW

Schematic

PRESSURE REDUCING VALVE

w i t h LOW-FLOW BY-PASS FEATURE

06/08

M115-74 (Globe)

M1115-74 (Angle)

Throttles to reduce high upstream pressure to •
constant lower downstream pressure

Low Flow By-Pass controls at low ows•

Main Line valve controls at high ows•

Reducing and Low Flow By-Pass setpoints are •
separately adjustable

Standard Components

1 – Main Valve (Single Chamber)
2 – Pressure Reducing Control

3 – Fixed Orice

4 – Low Flow By-Pass

Options & Accessories

X – Isolation Cocks ○
FC – Flo-Clean Strainer ○
Y – Y-Strainer (Replaces Flo-Clean) ○
ACS – Adjustable Closing Speed ○

(Replaces Fixed Orice)

AOS – Adjustable Opening Speed ○
P – Position Indicator ○
L – Limit Switch ○

(2)

(1)

(3)

(3)

(1)

Standard 3” & Smaller

(2)

Standard 4” & Larger

(3)

Optional All Sizes

(2)

(3)

(1)

Operations

The Watts ACV Pressure Reducing Control Valve with Low Flow By-Pass is designed to automatically reduce a

uctuating higher upstream pressure to a constant lower downstream pressure regardless of varying ow rates. It
is controlled by a normally open, pressure reducing pilot designed to: 1) Open (allowing uid out of the main valve
cover chamber) when downstream pressure is below the adjustable setpoint, and 2) Close (allowing uid to ll the
main valve cover chamber) when downstream pressure is above the adjustable setpoint. A decrease in downstream
pressure causes the valve to modulate toward an open position, raising downstream pressure. An increase in
downstream pressure causes the valve to modulate toward a closed position, lowering downstream pressure.

A Low Flow By-Pass Valve is piped parallel to the Main Pressure Reducing Valve, and is set approximately 10 PSI
higher. The Low Flow By-Pass handles ow requirements below the range of the Main Pressure Reducing Valve.

During “off peak” demand conditions, the Low Flow By-Pass provides ow and pressure to the downstream zone.
As ow requirements increase beyond the capacity of the Low Flow By-Pass, downstream pressure falls below the
setpoint of the Main Pressure Reducing Valve allowing it to throttle toward open, supplementing ow and pressure.
As ow requirements decrease, downstream pressure rises above the setpoint of the Main Pressure Reducing Valve,
causing it to throttle toward closed, allowing the Low Flow By-Pass to resume command of ow and pressure.

8550 Hansen Road • Houston, Texas 77075 • (Ph) 713.943.0688 • (Fx) 713.944.9445 • www.watts.com

Mu s t a n g se r i e s

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I J

M115-74 (Globe)

M1115-74 (Angle)

Materials

Globe

Angle

Body & Cover: Ductile Iron ASTM A536

Coating: NSF Listed Fusion Bonded

Epoxy Lined and Coated

Trim: 316 Stainless Steel

Elastomers: Buna-N (standard)

EPDM

Viton

Stem, Nut & Stainless Steel
Spring:

Operating Pressure Operating Temperature Pilot System Tubing & Fittings

Threaded = 400 psi

150 Flanged = 250 psi

300 Flanged = 400 psi

Buna-N: 160°F Maximum

EPDM: 300°F Maximum

Viton: 250°F Maximum

Reducing Control Copper / Brass (Standard)

30-300 psi (Standard) Stainless Steel (Optional)

0-30 psi (Optional)

Low Flow By-Pass

20-200 psi (Standard)

Dimensions

A B C D E F G H I J K L

VALVE

GLOBE

SIZE

1-1/4 7-1/4 - - 5-1/2 3-1/4 - - 1-7/8 - - 3/8 1/4 20

1-1/2 7-1/4 8-1/2 9 5-1/2 3-1/4 4 4-1/4 1-7/8 4 4-1/4 3/8 1/4 25

2-1/2 11 11 11-5/8 7-1/2 5-1/2 5-1/2 5-7/8 4 4 4-5/16 1/2 1/2 65

THRD.

2 9-3/8 9-3/8 10 6-1/2 4-3/4 4-3/4 5 3-1/4 3-1/4 3-1/2 3/8 1/2 40

3 12-1/2 12 13-1/4 8-1/4 6-1/4 6 6-3/8 4-1/2 4 4-3/8 1/2 1/2 95

4 - 15 15-5/8 10-5/8 - 7-1/2 7-7/8 - 5 5-5/16 3/4 3/4 190

6 - 20 21 13-3/8 - 10 10-1/2 - 6 6-1/2 3/4 3/4 320

8 - 25-3/8 26-3/8 16 - 12-3/4 13-1/4 - 8 8-1/2 1 1 650

10 - 29-3/4 31-1/8 17-1/8 - 14-7/8 15-9/16 - 8-5/8 9-5/16 1 1 940

GLOBE

150#

GLOBE

300#

COVER TO

CENTER

ANGLE

THRD.

ANGLE

150#

ANGLE

300#

ANGLE

THRD.

ANGLE

150#

ANGLE

300#

PORT

SIZE

PORT

SIZE

SHIPPING

WEIGHTS*

For larger sizes consult factory

Valve Cover Chamber Capacity

Valve Size (in) 1-1/4 1-1/2 2 2-1/2 3 4 6 8 10

U.S. Gal - - - - - - -

.oz. 4 4 4 10 10 22 70

- -

1-1/4 2-1/2

Valve Travel

Valve Size (in) 1-1/4 1-1/2 2 2-1/2 3 4 6 8 10

Travel (in) 3/8 3/8 1/2 5/8 3/4 1 1-1/2 2 2-1/2

8550 Hansen Road • Houston, Texas 77075 • (Ph) 713.943.0688 • (Fx) 713.944.9445 • www.watts.com

M115-74 (Globe)

Pressure Drop

Flow

20

3/4”

1/2”

15105

0

0

10

20

30

40

CAVITATION ZONE

INLET PRESSURE - PSI

OUTLET PRESSURE - PSI

300

280

260

240

220

200

180

160

140

120

100

80

60

40

20

0 10 20 40 50 60 70 80 90

130 14012011 0100

30

CAVITATION CHART

Mu s t a n g se r i e s

Sizing

Size (in) 1-1/4 1-1/2 2 2-1/2 3 4 6 8 10

Maximum Continuous (GPM) 100 150 200 300 460 800 1800 3100 4900

Maximum Intermittent (GPM) 119 161 265 390 590 1000 2300 4000 6250

Minimum Continuous (GPM) 1 1 1 20 30 50 115 200 300

Maximum continuous ow based on velocity of 20 ft. per second.

Maximum intermittent ow based on velocity of 25 ft. per second.

Minimum continuous ow based on velocity of 1 ft. per second.

NOTE: The above chart is a suggested guide. Inlet pressure, outlet pressure, minumum, normal and maximum ow rates should
be considered for specic valve sizing. Contact Watts ACV for details.

Low-Flow By-Pass

Valve Size (in) By-Pass (in) Adjustment

Range

2-1/2 &

Smaller

3 & Larger 3/4

1/2 20-200 psi

M1115-74 (Angle)

Cavitation Chart

After selecting the valve size, locate

inlet and outlet pressures on this

chart. If the intersection point falls

in the shaded area, cavitation can
occur. Operation of valves continu­ally in the cavitation zone should be

avoided. Consult Watts ACV for al­ternatives.

8550 Hansen Road • Houston, Texas 77075 • (Ph) 713.943.0688 • (Fx) 713.944.9445 • www.watts.com

Mu s t a n g se r i e s

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Cross-Sectional Detail

Main Valve

M115-74 (Globe)

M1115-74 (Angle)

ITEM DESCRIPTION MATERIAL

1 Cover ASTM A536 65-45-12 Epoxy Coated Ductile Iron

2 Cover Bearing ASTM A276 304 Stainless Steel

3 Shaft / Stem ASTM A276 304 Stainless Steel

4 Stud ASTM A570 Gr.33 Zinc Plated Steel

5 Cover Nut ASTM A570 Gr.33 Zinc Plated Steel

6 Diaphragm* Buna-N (Nitrile)

7 Body ASTM A536 65-45-12 Epoxy Coated Ductile Iron

8 Seat Disc* Buna-N (Nitrile)

9 Seat Ring ASTM A743 CF8M (316) Stainless Steel

10 Spring ASTM A276 302 Stainless Steel

11 Stem Nut ASTM A276 304 Stainless Steel

12 Spring Washer ASTM A276 304 Stainless Steel

13 Diaphragm Washer ASTM A536 65-45-12 Epoxy Coated Ductile Iron

14 Disc Retainer ASTM A536 65-45-12 Epoxy Coated Ductile Iron

15 Spacer Washer* Fiber*

16 Disc Guide ASTM A743 CF8M (316) Stainless Steel

17 Seat Gasket* Buna-N (Nitrile)

* Contained in Main Valve Repair Kit

8550 Hansen Road • Houston, Texas 77075 • (Ph) 713.943.0688 • (Fx) 713.944.9445 • www.watts.com

Mu s t a n g se r i e s

Controls and Accessories

Model CP-15

Pressure Reducing Pilot

M115-74 (Globe)

M1115-74 (Angle)

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Front View Side View

ITEM

NUMBER

1 Adjusting Screw

2 Jam Nut

3 Spring Housing

4 Spring

5 Cap Screw

6 Body

7 Seat

8 O-Ring*

9 Bottom Cap

10 Spring Guide

DESCRIPTION

9

ITEM

NUMBER

11 Nut

12 Belleville Washer

13 Diaphragm Washer

14 Diaphragm *

15 Yoke

16 Disc and Retainer Assembly*

DESCRIPTION

* Included in Repair Kit

8550 Hansen Road • Houston, Texas 77075 • (Ph) 713.943.0688 • (Fx) 713.944.9445 • www.watts.com

M115-74 (Globe)

Mu s t a n g se r i e s

Installations

Prior to installation, ush line to remove debris.•
Install valve horizontally “in line” (cover facing UP), so ow arrow matches ow through the line. • Avoid install-
ing valves 6” and larger vertically. Consult factory prior to ordering if installation is other than described.
Install inlet and outlet isolation valves. • NOTE: When using buttery valves, insure disc does not contact control
valve. Damage or improper valve seating may occur.
Provide adequate clearance for valve servicing and maintenance.•
Install pressure gauges to monitor valve inlet and outlet pressure.•
If installation is subjected to very low ow or potentially static conditions, it is recommended a pressure relief •
valve (1/2” minimum) be installed downstream of the Pressure Reducing Valve for additional system protec­tion.

Start-Up

Proper Automatic Control Valve start-up requires bringing the valve into service in a controlled manner. All

adjustments to control pilots and speed controls should be made slowly, allowing the valve to respond and the

system to stabilize. NOTE: Control Valves should be set‑up in a dynamic (owing) condition for proper
start‑up. Provisions for ow must be made to insure proper settings.

For proper operation, the Low Flow By-Pass is set 10 PSI • higher than the Main Pressure Reducing

Valve.

M1115-74 (Angle)

Close upstream and downstream valves to isolate the valve from line pressure. Release spring tension on 1.

Pressure Reducing Control and Low Flow By-Pass by turning adjustment screws out (counterclockwise),

decreasing setpoints. Open all Isolation Ball Valves, if so equipped. If valve is tted with adjustable speed
controls, turn needle(s) in (clockwise) until seated, and return out (counterclockwise) 1-1/2 to 2-1/2 turns.
These are approximate settings, and should be ne tuned to suit system requirements after pressure
adjustments have been made.

Slowly open upstream isolation valve to allow controlled lling of the valve. Vent entrapped air by carefully 2.
loosening control tubing or pipe plug at the highest point possible. If valve is equipped with a Position
Indicator, open Air Bleed Petcock to vent air. Water will be milky in appearance and will begin to clear as
air is vented. Carefully loosen enough cover screws on control pilot(s) to vent entrapped air. Re-tighten
when water vents clearly.

Setting Reducing Control:3. Slowly open downstream isolation valve. Gradually turn adjustment screw on
the Pressure Reducing Control in (clockwise) to raise downstream pressure. Allow valve and system to
stabilize. Observe inlet and outlet pressure gauges. Continue to adjust as needed, pausing approximately
every 1-1/2 turns, allowing valve and system to stabilize. Turning adjustment screw clockwise raises outlet
pressure. Turning adjustment screw counterclockwise lowers outlet pressure. Set Pressure Reducing
Control approximately 10 PSI lower than desired downstream pressure. Tighten locknut on Reducing
Pilot.

Fine tune Speed Controls to suit system requirements. Adjust Closing Speed Control (if equipped) 4.
clockwise for slower closure, and counterclockwise for faster closure. Adjust Opening Speed Control (if
equipped) clockwise for slower opening, and counterclockwise for faster opening.

Setting Low Flow By-Pass:5. Gradually turn adjustment screw on Low Flow By-Pass in (clockwise) to

raise downstream pressure. Observe outlet pressure gauge. Continue to adjust Low Flow By-Pass,

pausing approximately every 1-1/2 turns, allowing valve and system to stabilize, until desired downstream

pressure is reached. Low Flow By-Pass is now set approximately 10 PSI higher than the Main Pressure
Reducing Valve, and will handle low ow requirements. Tighten locknut on Low Flow By-Pass Pilot.

8550 Hansen Road • Houston, Texas 77075 • (Ph) 713.943.0688 • (Fx) 713.944.9445 • www.watts.com

M115-74 (Globe)

Mu s t a n g se r i e s

Specications

The Pressure Reducing Control Valve with Low Flow By-Pass shall be a pilot operated diaphragm valve

designed to automatically reduce a uctuating higher upstream pressure to a constant lower downstream
pressure regardless of varying ow rates. Flow requirements below the normal range of the main line

Pressure Reducing Control Valve shall be handled by a valve mounted, direct acting, Low Flow By-Pass

valve.

The main valve shall be a hydraulically operated, single diaphragm actuated, globe or angle pattern valve.
Y-pattern valves shall not be permitted. The valve shall contain a disc and diaphragm assembly that forms
a sealed chamber below the valve cover, separating operating pressure from line pressure. The diaphragm
shall be constructed of nylon reinforced Buna-N, and shall not seal directly against the valve seat and shall
be fully supported by the valve body and cover. Rolling diaphragm construction will not be allowed and there
shall be no pistons operating the main valve or any pilot controls.

The main valve body and cover shall be Ductile Iron ASTM A536, and all internal cast components shall

be Ductile Iron or CF8M (316) Stainless Steel. All Ductile Iron components, including the body and cover,
shall be lined and coated with an NSF 61 Certied Epoxy Coating applied by the electrostatic heat fusion
process. All main valve trim and throttling components (cover bearing, valve seat and disc guide) shall
be Stainless Steel. The valve body and cover must be machined with a 360-degree locating lip to assure
proper alignment.

M1115-74 (Angle)

The disc and diaphragm assembly shall contain a Buna-N synthetic rubber disc with a rectangular cross-

section that is securely retained on 3-1/2 sides by a disc retainer and disc guide. Diaphragm assemblies
utilizing bolts or cap screws for component retention will not be permitted.

The exposed portion of the seat disc shall contact the valve seat and seal drip-tight. The disc and diaphragm

assembly must be guided by two separate bearings, one installed in the valve cover and one concentrically

located within the valve seat, to avoid deection and assure positive disc-to-seat contact. Center guided
valves will not be permitted. All necessary repairs shall be made from the top of the valve while the body
remains in line.

Pilot control systems for valves 3” and smaller shall contain a Flow Clean Strainer, Fixed Orice Closing
Speed, Adjustable Opening Speed Control, Low Flow By-Pass and Pressure Reducing Pilot. Pilot control
systems for valves 4” and larger shall contain an external Y-Strainer, Fixed Orice Closing Speed, Low
Flow By-Pass and Pressure Reducing Pilot. All pilot control systems shall utilize copper tubing and brass
ttings and must be equipped with Isolation Ball Valves on all body connections regardless of valve size.
The adjustment range of the Low Flow By-Pass shall be 20-200 psi and the pressure reducing pilot shall
be 30-300 psi.

The valve shall be Watts ACV Model M115-74 (Globe) or M1115-74 (Angle) pattern Pressure Reducing

Control Valve with Low Flow By-Pass.

Other Watts ACV Pressure Reducing Control Valves

M115 / M1115 Pressure Reducing Valve
M115-3 / M1115-3 Pressure Reducing Valve with Hydraulic Check Feature
M115-7 / M1115-7 Pressure Reducing Valve with Surge Control Feature

8550 Hansen Road • Houston, Texas 77075 • (Ph) 713.943.0688 • (Fx) 713.944.9445 • www.watts.com