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Murphy Lube Level Maintainer with Test Feature LM500-TF

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Murphy Lube Level Maintainer with Test Feature - LM500-TF

Product Condition: NEW
Murphy Lube Level Maintainer with Test Feature LM500-TF
Estimated ship date: for orders by 3pm PT/6pm ET today Available for back order.

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The Murphy LM500-TF Oil Level Maintainer includes a test feature that confirms both the float and switch are operating correctly with a single press of the test button. The LM500 series maintains the crankcase oil level of an engine, pump or compressor. Adjusted to the correct running-oil-level, it will replenish oil as it is used. The low-level switch will alarm and/or shutdown the equipment if supply oil is lost and the equipment continues to use oil. The LM500-TF maintains oil level on any size engine. It also supports installations that require a 3-wire, snap-action switch. The form C (3-wire) contact allows a controller/annunciator to be wired as a closed-loop system, resulting in a reliable fault-sensitive circuit.

As crankcase oil level drops, the LM500-TF float also drops and opens the Thumb-Valve. This allows oil to flow from the supply tank, through the LM500-TF, and into the crankcase. When proper level is achieved in the crankcase, the LM500-TF float rises, causing the Thumb-Valve to close off further oil flow. The simple and unique Thumb-Valve is non-clogging and provides a positive, leak-free seal.


  • Simple installation
  • Automatically maintains lube level
  • Low level, 3-wire, snap-action switch
  • Positive sealing Thumb-Valve
  • Eliminates under/overfill due to “human error”
  • See oil level and condition without shutting down
  • Test Feature (TF) allows test of float and switch



  • Part No.: LM500-TF
  • Crankcase Balance Vent Connection: 1/2 NPTF (top)
  • Inlet Connection: 1/2 NPTF removable screen (side)
  • Outlet Connection:2 x 3/4 NPTF (side) 1 x 3/4 NPTF (bottom)
  • Thumb-Valve Material: Viton
  • Snap-switch: SPDT rating 10 A, 125 VAC; 0.5 A, 125 VDC; 10 A, 30 VDC
  • Wire leads: 18 AWG x 14 in. ± 2 in. (355 mm) length
  • Conduit Connection: 1/2 inch conduit (female, top)
  • Case: Die cast aluminum
  • Lens: Clear “Frog Eye” non-staining, high impact, high temperature polycarbonate; UV and heat stabilized
  • Dial: High visibility white background with solid green band for normal level indication
  • Maximum Inlet Pressure: 9.50 psi/25 ft. oil (head pressure)
  • Maximum Case Pressure: 15 psi (103 kPa)
  • Maximum Differential: 2 in. (51 mm) between running and stopped
  • Maximum Ambient Temperature: 250°F (121°C)
  • Float: 304 Stainless Steel
  • Flow Rates: Refer to image #4
  • Dimensions: Overall 6-9/16 inch tall x 6-3/16 inch deep x 3-1/2 deep
  • Shipping Dimensions: 9.5 x 7.5 x 11 in. (241.3 x 190 x 279.4 mm)
  • Shipping Weight: 3 lbs. 13.44 oz (1.74 kg)

NOTE: Holding test button in for a prolonged period of time could cause crank case to over fill.

Additional Information

Product Condition NEW
upc No

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