Murphy L971 Series Specifications

Crankcase Level Switch
**
Description
The Murphy L971 Series Level Switch detects
low oil level in a compressor's crankcase.
As oil level in the crankcase depletes, the
float on the L971 switch falls, and if reaches
the predetermined limit, will trip the internal
snap-switch which in turn will initiate a
shutdown and/or alarm.
The L971 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 explosionproof enclosure,
durable SPDT snap-switch and rigid
polyurethane foam float. A 304 stainless steel
float is available on certain configurations (see
Specifications).
Specifications
Operating Temperature Range:
-15 to 275°F (-26 to 135°C).
Maximum Working Pressure:
30 psi (206 kPa) [2.06 bar].
L971 Series
■ Durable Low Level Switch
■ Replaces Non-Explosion-proof Switch on
Ingersoll-Rand Compressors
■ Adaptable to Other Compressors
■ Installs with Minimal Downtime
R
■ Two Year Limited Warranty
Switch Rating: 4 A @ 250 VAC.
Material
Case: Aluminum (explosion-proof).
Mounting Adaptor: Brass.
Floats: Rigid polyurethane. 304 stainless
steel available on 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
Shipping Weight: 1 lb. 10 oz. (0.7 kg).
Shipping Dimensions: 8-1/4 x 4-1/4 x
4-1/2 in. (210 x 108 x 114 mm).
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.
Catalog Section 15

Wiring Diagrams

Model L971-A
Green
Yellow
All Other Models
Green
Yellow
*
Shown in "shelf" position with no force acting upon float.
**
Products covered by this bulletin comply with EMC
Council directive 89/336/EEC regarding electromagnetic
compatibility except as noted.
L-7229B
Revised 02-97
(00-02-0059)
*
Red
Black
Red