Fluid Level Switches and Maintainers


Oil Level Maintainer

LM500-TF oil level maintainerThe Murphy LM500 series gives automatic maintenance of crankcase oil level, for industrial engine applications such as pumps, compressors and power generators.

Adjusted to the correct running-oil-level, the LM500 will replenish oil as it is used. The devices reduce ongoing oil level maintenance and eliminate problems due to oil underfill or overfill.

The low-level switch will alarm and/or shutdown the equipment if supply oil is lost and the equipment continues to use oil. Model LM500-TF also includes a switch test facility, for checking correct alarm/shutdown operation.


  • Automatic oil level maintainance, reducing engine servicing
  • Eliminates under/overfill due to 'human error'
  • Float control with positive sealing Thumb-Valve™
  • 'Frogeye' lens gives clear indication of oil level and condition
  • Simple installation, direct mount capable (DM bracket option)
  • Low oil level snap-action switch (insulated, 3-wire)
  • Test Feature (TF model) for operator test of float and switch
  • LM500-TF-ATEX model for ATEX Zone 2, category 3G

Not intended for use with fuel


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