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LM-92164N page 4 of 4

OPERATING RANGES OF SWITCHES

3/4 in.

(19 mm)

Normal 
Operating Range

Low Zone 
Shutdown or Alarm

High Zone 
Shutdown or Alarm

3/8 in.

(10 mm)

3/8 in.

(10 mm)

3/4 in.

(19 mm)

Normal 
Operating Range

Low Zone Alarm
Low-Low Zone Shutdown

3/4 in.

(19 mm)

3/8 in.

(10 mm)

1/4 in.

(6 mm)

SWITCH WIRING DIAGRAMS

LM301

SPDT

LM302

High/Low N.O.

DPST

LM303

High/Low N.C.

DPST

Green

Black

Normal

Red

Low

Float

Yellow

Green

Black

High

Float

High

Red

Low

Yellow

Normal

Low

Normal

Green

High

Float

High

Low

Blue

Normal

Low

Normal

Brown

Orange

Green

Normal

Float

Normal

Low-Low

Yellow

Low

Low-Low

Low

Black

Red

Green

Normal

Float

Normal

Low-Low

Blue

Low

Low-Low

Low

Brown

Orange

LM304

Alarm before 

shutdown N.O.

DPST

LM305

Alarm before 

shutdown N.C.

DPST

Normal 
Operating Range

Low Zone 
Shutdown or Alarm

3/4 in.

(19 mm)

3/8 in.

(10 mm)

Figure 7:

LM301

Figure 9: 

LM304/LM305

Figure 8: 

LM302/LM303

This section applies only to models that have built-in switches. The illustrations
below and to the right show the dials and their operating ranges of the switches.
If levels are within the designated zones the switch(es) will activate. 

Notice

that

a switch is capable of activating approximately 3/8 in. (10 mm) from the top of
the high zone and 3/8 in. (10 mm) from the bottom of the low zone. The dial in

Figure 9

shows that if level continues to drop into the low-low zone, a

shutdown will occur.

NOTE:

Color zones on dial face show approximate normal operating zones.

Actual conditions may vary depending upon operating characteristics of the
engine. Placement of the LM300 according to the above instructions will
compensate for these conditions.

WARNING:

DISCONNECT ALL ELECTRICAL POWER BEFORE CONNECTING ANY WIRES.

CONTROL SYSTEMS & SERVICES DIVISION

P.O. Box 1819; Rosenberg, Texas 77471; USA
+1 281 633 4500  

fax

+1 281 633 4588 

e-mail

[email protected]

MURPHY DE MEXICO, S.A. DE C.V.

Blvd. Antonio Rocha Cordero 300, Fracción del Aguaje 
San Luis Potosí, S.L.P.; México 78384 
+52 444 8206264  

fax

+52 444 8206336

Villahermosa 52 993 3162117

e-mail

[email protected]

www.murphymex.com.mx

FRANK W. MURPHY, LTD.

Church Rd.; Laverstock, Salisbury SP1 1QZ; U.K.
+44 1722 410055  

fax

+44 1722 410088  

e-mail

[email protected]

www.fwmurphy.co.uk

MURPHY SWITCH OF CALIFORNIA

41343 12th Street West
Palmdale, California 93551-1442; USA
+1 661 272 4700  

fax

+1 661 947 7570

e-mail

[email protected]

www.murphyswitch.com

In order to consistently bring you the highest quality, full featured products, we reserve the right to change our specifications and designs at any time.

MACQUARRIE CORPORATION

1620 Hume Highway
Campbellfield, Vic 3061; Australia 
+61 3 9358 5555  

fax

+61 3 9358 5558

e-mail

[email protected] 

FW Murphy 

P.O. Box 470248
Tulsa, Oklahoma 74147 USA 
+1 918 317 4100 

fax

+1 918 317 4266  

e-mail 

[email protected]  

www.fwmurphy.com

R

E

G ISTERE

D

USA–ISO 9001:2000 FM 28221

UK–ISO 9001:2000 FM 29422

Printed in U.S.A.

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

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