Murphy L971 Series User Manual
Warning, Description, Specifications

Installation Instructions for
L971 Series Crankcase Level Switch
L-94071N
Revised 09-97
Section 15
(00-02-0173)
Description
The Murphy L971 Series Level Switch detects low oil level in a com-
pressor’s crankcase. It is designed for Ingersoll-Rand Type 30, Type 40
and ESH compressors, yet can be adapted to fit other compressors that
have an inspection plate extending below normal operating oil level.
The L971 has a 1/2 NPT process connection and features an explosion-
proof enclosure, durable SPDT snap-switch and rigid polyurethane
foam float.
Specifications
Operating Temperature: -15 to 275°F (-26 to 135°C).
Maximum Working Pressure: 30 psi (206 kPa) [2.06 bar].
Switch Rating: 4 A @ 250 VAC.
Material
Case: Aluminum (explosion-proof).
Mounting Adaptor: Brass.
Floats:
• Rigid polyurethane.
• 304 stainless steel (L971-C only).
Other Wetted Parts: 303, 304, and 316 stainless steel.
O-Ring Seals: Viton and Buna.
Process Connection: 1/2 NPT.
Enclosure Rating: UL and CSA listed for Class I, Groups C & D;
Class II, Groups F & G, Hazardous Locations.
Conduit Connection: 1/2 NPT.
Wire: 18 AWG (0.75 mm
2
).
Please read the following information before installing. A visual inspection of this product for damage during shipping is recom-
mended before mounting. It is your responsibility to have a qualified person install this unit and make sure it conforms to local codes.
GENERAL INFORMATION
WARNING
BEFORE BEGINNING INSTALLATION OF THIS MURPHY PRODUCT
✔
Disconnect all electrical power to the machine.
✔
Make sure the machine cannot operate during installation.
✔
Follow all safety warnings of the machine manufacturer.
✔
Read and follow all installation instructions.
R
Dimensions
A
B
C
D
E
L971
2-5/8 (67)
5-7/8 (149)
30 (762)
2-1/2 (64)
2-27/32 (72)
L971-A
2-5/8 (67)
5-7/8 (149)
30 (762)
2-1/2 (64)
2-27/32 (72)
L971-B
4-13/16 (122)
8-1/16 (205)
30 (762)
4-5/8 (117)
2-27/32 (72)
L971-C
2-13/16 (71)
6-1/16 (154)
30 (762)
2-7/8 (73)
3-1/8 (79)
L971-D
3-7/8 (98)
7-1/8 (181)
30 (762)
3-3/4 (95)
2-27/32 (72)
L971-E
4-13/16 (122)
8-1/16 (205)
30 (762)
5-1/8 (130)
2-27/32 (72)
L971-F
2-5/8 (67)
5-7/8 (149)
40 (1016)
2-1/2 (64)
2-27/32 (72)
L971-G
2-5/8 (67)
5-7/8 (149)
40 (1016)
2-1/2 (64)
2-27/32 (72)
*Millimeter dimensions are shown in parenthesis ( ).
Dimensions in inches*
(see drawing above)
Models
D
A
Float arm is
adjustable but
cannot be
removed.
1/2 NPT
Float is removable
and replaceable
3 in.
(76 mm)
1/2 NPT
B
C
E
**
Products covered by this literature comply with EMC Council directive 89/336/EEC regarding electromagnetic compatibility except as noted.
**
L-94071N page 1 of 2
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