• Murphy by Enovation Controls

LM300 Series

The LM300 Series Level Maintainer automatically adds oil to the crankcase as needed to keep the lube level normal.

Most models have built-in switches that will alarm and/or shut down the equipment if the makeup supply is depleted and engine oil level falls or if overfill conditions exist. The LM300 can be used in engines, compressors, pumps and coolers. LM300 Series EX models (explosion-proof) are CSA certified for Class I, Division 1 Hazardous areas.

  • CE (European Conformity) mark
  • CSA mark (for the United States)
Specifications Downloads How to Order
Specifications Drawer: 
  • Case/Cover: Die cast aluminum
  • Switch Housing: Aluminum
  • Approval Rating: All CSA Certified with switch contacts rated at 10 A at 250 VAC (standard)
    • LM301 through LM305: CSA certified for non-hazardous locations. Enclosure Type 4 certified
    • LM301-EX through LM305-EX: CSA certified for Class I, Groups C and D; Class II, Groups F and G hazardous locations. Enclosure Type 4 certified.
  • Float: Rigid polyurethane foam; Polyurethane coated
  • Max. Ambient Temperature: 250° F (121° C)
  • Oil Inlet Connection: Top entry 1/2-14 NPT with built-in filter screen (removable for cleaning)
  • Inlet Orifices: 1/4 in. (6 mm) standard; 1/8 in. (3 mm) available
  • Wire (switch models): 18 AWG x 13 in. (1.0 mm2 x 330 mm) Max. Inlet Pressure (MIP):
    • 30 psi (207 kPa) [2.07 bar] with 1/8 in. (3 mm) orifice
    • 15 ft oil (4.6 m oil) with 1/4 in. (6 mm) orifice
  • Max. Differential: 2 in. (51 mm) between running and stationary oil level
  • Max. Case Pressure (MCP): 15 psi (103 kPa) [1.03 bar] Orifice Seal: Buna-N Thumb-Valve Switch Contact: Silver, SPDT snap-acting, rated at 10 A @ 125, 250 VAC; 10 A @ 30 VDC (1 only for low level; 2 only for high and low; or 2 only for low level with alarm before shutdown)
  • Outlet Connection: 3/4-14 NPT left side, right side and bottom
  • Crankcase Balance Vent Fitting: 1/2-14 NPT
  • Mounting: Accepts Murphy pipe or universal mounting brackets
  • Lens: Clear Frog Eye non-staining, high-impact, high-temperature nylon; UV and heat stabilized
  • Glass Lens: Available on LM301 and LM301-EX models. Specify GL as part of model number when ordering
  • Dial: High visibility white background with green and white index lines for normal level indication
  • Test Knob: Rotate to test switch operation. Turn clockwise for low level test and turn counterclockwise for high level test.

WARNING: This product may expose you to chemicals which are known to the State of California to cause cancer, birth defects or other reproductive harm. For more information about California Propsition 65, go to www.P65Warnings.ca.gov or visit our California Proposition 65 page.

Literature Drawer: 

Additional product documentation can be found on our product support website or by clicking the Help Center button above.

Additional Order Items

Part NumberDescription
15000370Universal Bracket Kit
15000371Pipe Bracket Kit
15000354Bubble Lens Assembly
15000355Hose Kit
15000539Glass Lens Kit
(LM301 and LM301-EX only)
15000357Regulator Float Repair Kit


15000355 Hose Kit Parts

11/2 in. (13 mm) I.D. x 3 ft. (914 mm) long hose
11 in. (25 mm) I.D. x 3 ft. (914 mm) long hose
21/2 in. (13 mm) worm gear clamp
21 in. (25 mm) worm gear clamp
21/2 NPT x 1/2 in. (13 mm) barbed fitting
23/4 NPT x 1 in. (25 mm) barbed fitting