Murphy M50, M25 User Manual

M25 and M50 Series

■

Instant Response to Shut Off Signal

■

Positive Valve Closure

■

Vents Gases Trapped After Shutdown

■

Explosion-proof Models Available

■

Models Available for Magneto,
CD Ignition or 12/24 VDC

■

Normally Energized Model Available

Description

These fuel shutoff valves are semi-automatic
devices for shutdown of natural gas fueled
engines. The valve is opened manually and closes
when the electromagnet is energized and trips the
latch. The valve can be closed manually by turning
the valve’s disconnect knob. A normally energized
model is available that holds the valve open elec­trically and closes when the coil is de-energized. A
vent in the valve body relieves trapped gas when
the valve closes. A pop-out indicator button
informs you when the valve is open or closed.

The valve’s tripping power is provided by an
engine ignition system or battery. Models are avail­able for magneto, CD ignition or 12/24 V battery.

The M2582 is a 1 inch (25 mm) valve with 1
NPT connections. It has one SPDT snap-switch.
The valve body is made of sandcast aluminum. It
does not include the open/close indicator button.

M5081 is a 2 inch (51 mm) valve with 2 NPT
connections. It has two SPDT snap-switches.
The valve body is available in sandcast alu­minum or cast steel (optional).

M5081FS is the same as the M5081 but has a
normally energized circuit. This circuit allows
the valve to be held open electrically and close
by interruption of the coil’s power circuit. A

manual trip knob is not available on this model.

An optional 2 in. (51 mm) steel flange pipe con­nection is available for M5081 and M5081FS
steel body models (see Dimensions page 3).

Specifications

Valve Body: Sandcast aluminum, painted

red (corrosion resistance). Optional cast
steel available for M5081 and M5081FS
models only.

Valve Seat: Buna-N

Maximum Pressure Rating:

• M2582: 80 psig (552 kPa) [5.52 bar]

• M5081: 100 psig (689 kPa) [6.89 bar]

• M5081FS: 100 psig (689 kPa) [6.89 bar]
Coil Rating: Intermittent duty; coil

type must match power source;

• CD ignition coil resistance: 72 Ω
CD primary voltage: 1.38 to 3.8 A

• M5081FS model: Energized to run

(continuous-duty coil) coil resistance:

12 Volt model: 33 Ω (0.36 A)
24 Volt model: 136 Ω (0.17 A)

• Magneto ignition coil resistance: 0.5 Ω

• Magneto primary voltage: 1 to 5 A

• Battery coil resistance : 7 Ω
12 or 24 VDC: 1.2 to 2.4 A

Wiring (See Internal Wiring page 2):

• M2582: Wire leads

• M5081 and M5081FS: Terminal blocks

Snap-switch Rating: 5 A @ 480 VAC

Laboratory Approval: CSA listed for Class I,

Groups C and D Hazardous Locations. 5 amps
maximum; intermittent duty; models M5081 and
M5081-CD engine ignition powered, and model
M5081-B, 12 or 24 VAC or VDC; switch con­tacts rated 5 A @ 480 VAC maximum.

Options and Accessories

Diode Package (65010065)

The Murphy 202 V diode package is designed to
allow the fuel shutoff valve to be used with dual
Magneto Ignition systems. Sold separately (see
How to Order).

Magnetic Switch Adapter

As ignition systems wear from usage their power
output becomes less and less. Ignition may not
have the capacity to reliably trip the fuel valve.
Therefore, the use of a Magnetic Switch Adapter
for CD ignition systems is recommended. The
adapter stores energy from the CD ignition to
trip the fuel valve. Three models are available:

65020126: For Negative Ground CD Ignitions

up to 240 VDC

65020127: For Positive Ground CD Ignitions up

to 450 VDC

65020155: For Negative Ground CD Ignitions

240 VDC to 450 VDC

Warranty

A limited warranty on materials and workmanship
is given with this FW Murphy product. A copy of
the warranty may be viewed or printed by going to
www.fwmurphy.com/support/warranty.htm

Model M5081

MV-94134B

Revised 07-99

Catalog Section 55

(00-02-0124)

Electromechanical
Fuel Shutoff Valves

250

[7.08]

500

[14.16]

1000

[28.32]

1250

[35.40]

1500

[42.48]

1750

[4956]

2000

[56.64]

2250

[63.72]

2500

[70.80]

3000

[84.96]

2750

[77.88]

750

[21.24]

0

1.0

[25.4]

2.0

[50.8]

3.0

[76.2]

4.0

[101.6]

5.0

[127.0]

6.0

[152.4]

7.0

[177.8]

8.0

[203.2]

9.0

[228.6]

10.0

[254.0]

4 oz. (0.11 kg.)

10 oz. (0.28 kg.)

5 psig (34 kPa) [0.34 bar]

10 psig (69 kPa) [0.69 bar]

20 psig (138 kPa) [1.38 bar]

30 psig (207 kPa) [2.07 bar]

4 oz. (0.11 kg.)

10 oz. (0.28 kg.)

5 psig (34 kPa) [0.34 bar]

10 psig (69 kPa) [0.69 bar]

20 psig (138 kPa) [1.38 bar]

30 psig (207 kPa) [2.07 bar]

4 oz. (.11 kg.)

10 oz. (.28 kg.)

10 psig (69 kPa) [.69 bar]

20 psig (138 kPa) [1.38 bar]

30 psig (207 kPa) [2.07 bar]

M2582

M5081 and M5081FS

M2582

M5081 and M5081FS

Inches water column (∆p) drop across valve.

Millimeters water column in brackets [ ].

Standard cubic feet per hour. Cubic meters per hour in brackets [ ].

Inches water column (∆p) drop across valve.

Millimeters water column in brackets [ ].

Standard cubic feet per hour. Cubic meters per hour in brackets [ ].

Internal WiringFlow Rates

NOTE: For grounding the ignition (CD models only) through the fuel
valve’s internal snap-switch, a Murphy Magnetic Switch adapter (see page 4)
must be used in addition to a 100 ohm, 2 watt resistor (supplied with valve).

NOTE: For grounding the ignition (CD models only) through the fuel
valve’s internal snap-switch, a Murphy Magnetic Switch adapter (see page 4)
must be used in addition to a 100 ohm, 2 watt resistor (supplied with valve).

MV-94134B page 2 of 4

Optional
Resistor
(See Note)

White

Black

Red

Ground

3.0

[76.2]

2.0

[50.8]

1.0

[25.4]

500

0

[14.16]

[28.32]

1000

2000

1500

[42.48]

2500

[56.64]

[70.80]

4 oz. (.11 kg.)

4 oz. (.11 kg.)

10 oz. (.28 kg.)

10 oz. (.28 kg.)

a) [.69 b

a

9 kP

(6

(69 kP

sig

sig

10 p

10 p

20 psig (138 kPa) [1.38 bar]

20 psig (138 kPa) [1.38 bar]

30 psig (207 kPa) [2.07 bar]

30 psig (207 kPa) [2.07 bar]

3000

3500

4000

[84.96]

[99.12]

[113.28]

[127.44]

4500

ar]

ar]

) [.69 b

5000

[141.60]

M5081

Valve

Ground

10

Jumper

Disconnect Switches

Ignition 1 Ignition 2

Coil

7265 19384

Optional

Jumper

Resistor
(See Note)

Ground

10

M5081FS

Switch 2

Valve Coil

Switch 1

(see Note)

7265 19384



M2582

M5081 and M5081FS

Steel Flanged Option “3”

(available on M5081 and M5081FS steel body
configurations only)

Dimensions

MV-94134B page 3 of 4

Manual 
Disconnect
knob trips valve

1 NPT
(2 places)

1/4 NPT
Vent and 
Plug

Latching Handle

latches valve open

3-3/32 in.
(79 mm)

5-1/2 in. (140 mm)

1/2 NPT Conduit
Connection

7-5/16 in. 
(186 mm)

3-5/8 in.
(92 mm) 
diameter

2 in. (51 mm) dia. 

14-25/64 to 14-29/64 in.

(366/367 mm)

2 places 150# RF 
(raised face) pipe flange


45°

3/4 in. (19 mm) dia.
(4 places) each end
equally spaced on a
4-3/4 in. (121 mm) 
b.c. (bolt circle)


1/2 NPT 
Conduit


Inlet
Breather

Manual Disconnect
knob trips valve
(M5081 only)

Vent and Plug
1/2 NPT

latches valve open

9-3/8 in. (238 mm)

Latching Handle

1/2 NPT Conduit
Connection (2 plcs.)

10-5/16 in.
(262 mm)

Valve 
Open/Close
Indicator
Button


2 NPT

(2 places)

3 in. (76 mm)

7-3/4 in. (197 mm)

1-3/8 in. (35 mm)

3-7/16 in. 

(87 mm)

4-1/16 in. 
(103 mm)

Base Models

M2582
M5081
M5081FS

Trip Coil

A = Magneto ignition
B = Battery
C = CD ignition

Coil for M5081FS model only

A = 12 VDC
B = 24 VDC

Body Material

Blank = Aluminum
2 = Steel (M5081 and M5081FS only)
3 = Steel body with steel flange mounting

(M5081 and M5081FS only)

To order your valve, use the diagram below to specify your model and options.
Example: M5081-A-2

How to Order

Accessories

Specify part number when ordering.

Magnetic Switch Adapter

65020126: For Negative Ground CD Ignitions

up to 240 VDC

65020127: For Positive Ground

CD Ignitions up to 450 VDC

65020155: For Negative Ground

CD Ignitions 240 VDC to 450 VDC

Diode Package

65010065: For use with dual

Magneto Ignition systems.

_____ – __ – __

Shipping Information

Shipping Weights:

• M2582: 5 lbs 8 oz. (2.49 kg)

• M5081: 14 lbs 8 oz. (6.58 kg)

• M5081-2: 40 lbs (18.14 kg)

• M5081-3: 56 lbs (25.40 kg)

• M5081FS: 14 lbs 8 oz. (6.58 kg)

• M5081FS-2: 40 lbs (18.14 kg)

• M5081FS-3: 56 lbs (25.40 kg)

Shipping Dimensions:

• M2582: 8 x 8 x 7 in. (203 x 203 x 178 mm)

• M5081: 12 x 12 x 9-5/16 in. (305 x 305 x

237 mm)

• M5081-2: 12 x 12 x 9-5/16 in. (305 x 305 x

237 mm)

• M5081-3: 18 x 12 x 13-1/2 in. (457 x 305 x

343 mm)

• M5081FS: 12 x 12 x 9-5/16 in. (305 x 305

x 237 mm)

• M5081FS-2: 12 x 12 x 9-5/16 in. (305 x

305 x 237 mm)

• M5081FS-3: 18 x 12 x 13-1/2 in. (457 x

305 x 343 mm)

Service Parts

Specify part number when ordering.

M2582 M5081 M5081FS

“FS” Coil Assembly

12 VDC
24 VDC

Latch Block Assembly

Latch block assembly
Latch block switch and coil assembly
Latch block switch and mounting bracket assembly

Coil Assembly

Battery
CD Ignition
Magneto Ignition

55000128
55000129
55000094

55000096
55000097

55000137

55000102

55000102

55000095
55000144

55000074

55000118

55000158
55000159

55000126
55000127
55000080

Handle and Latch Kit

Handle and latch kit
Handle kit

Manual DIsconnect Assembly

55000098

55000072

55000160

Snap-switch Assembly

5500-0138

55000138

Close/Open Indicator Assembly

55000093

55000075

55000135

Stem and Seat Kit

55000194 (24V)

55000143 55000132

55000131

55000132

65020126

65020126

65010065

65020127

65020127
65020155

65020155

Vent Bushing Assembly
Diaphragm Assembly

Pilot Diaphragm

Single/Dual ign. – negative ground up to 240 VDC
Single/Dual ign. – positive ground up to 450 VDC

Single/Dual ign. – negative ground up to 450 VDC

Diode Package for Dual Magneto Ignitions
Magnetic Switch Adapter for CD Ignitions

55000146

55000161 (12V)

Top Works Complete Valve Less Body and Vent

MV-94134B page 4 of 4

CONTROL SYSTEMS & SERVICES DIVISION

P.O. Box 1819
Rosenberg, Texas 77471 USA
Phone: [phone] Fax: [phone]
E-mail: [e-mail]

FRANK W. MURPHY, LTD

Church Rd Laverstock
Salisbury SP1 1QZ UK
Phone: [phone] Fax: [phone]
E-mail: [e-mail]
Web site: www.fwmurphy.co.uk

COMPUTRONIC CONTROLS, LTD

41 - 43 Railway Terrace Nechells
Birmingham B7 5NG UK
Phone: [phone] Fax: [phone]
E-mail: [e-mail]
Web site: www.computroniccontrols.com

FW MURPHY INSTRUMENTS (HANGZHOU) CO. LTD

77 23rd Street
Hangzhou Economic & Technological Development Area
Hangzhou, Zhejiang 310018 China
Phone: [phone] Fax: [phone]

FW MURPHY

P.O. Box 470248
Tulsa, Oklahoma 74147 USA
[phone] Fax: [phone]
E-mail: [e-mail]

INDUSTRIAL PANEL DIVISION

Fax: [phone]
E-mail: [e-mail]

MURPHY POWER IGNITION

Web site: www.murphy-pi.com

www.fwmurphy.com

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