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Murphy Lube Level Maintainer LM304

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Murphy Level Maintainer with Two Switches DPST and 1/4 in. Orifice - Normally Open - LM304

Product Condition: NEW
Murphy Level Maintainer with Two Switches, Alarm Before Shutdown on Low Level and Shutdown on Low-Low Level LM304
Estimated ship date: for orders by 3pm PT/6pm ET today Available for Special Order

SSL Cerficate

The Murphy Level Maintainer with Two Switches DPST LM304 automatically adds oil to the crankcase as needed to keep the lube level normal. This model has a built-in switch that will alarm and/or shutdown the equipment if the makeup supply is depleted and engine oil level falls or if overfill conditions exist. NOTE: Friction losses due to piping NOT considered.

Applications: Engines • Compressors • Pumps • Coolers



  • Maintains proper lube level
  • Shutdown on low level, or high and low level
  • Manual float switch test
  • High visibility “Frog Eye” lens
  • Two switches. Alarm before shutdown on low level and shutdown on low-low level. Four wires, DPST, wired N.O. (Normally Open) in normal operating ranges
  • CSA certified with switch contacts rated at 10 A at 250 V AC (standard)



  • Part No.: LM304
  • Case/Cover: Die cast aluminum
  • Switch Housing: Aluminum
  • Approval Rating: CSA certified for non 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); Pressure: 4 ft. oil – 15 ft. oil (1.2 m oil – 4.6 m oil); Flow Rates: 4.7 GPH - 31.0 GPH (17.8 LPH - 117.3 LPH)
  • Wire (switch models): 18 AWG x 13 in. (1.0 mm2 x 330 mm)
  • Max. Inlet Pressure (MIP): 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)
  • Flow Rate Test: Using SAE 30 @ 32°F (0°C)
  • Outlet Connection: 3/4-14 NPT left side, right side, and bottom
  • Crankcase Balance Vent Fitting: 1/2-14 NPT
  • Mounting: Accepts Murphy pipe mounting bracket or universal mounting bracket
  • Lens: Clear “Frog Eye” non-staining, high impact, high temperature nylon; UV and heat stabilized
  • 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
  • Shipping Weight: 6 lbs. 6 ozs. (2.89 kg)
  • Shipping Dimensions: 10-5/8 x 8-7/8 x 6-3/4 in. (270 x 225 x 171 mm)

Additional Information

Product Condition NEW
upc No

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