Engine Fluid Level Switches and Maintainers


Engine Oil Level Maintainer

LM500-TF automatic engine oil level maintainerThe Murphy LM500 series gives automatic maintenance of engine 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 engine lubricating 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 engine oil level maintainance, reducing engine servicing
  • Eliminates oil under/overfill due to 'human error'
  • Float control with positive sealing Thumb-Valve™
  • Large '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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