15700837 – Murphy Lube Level Maintainer – LM500-TF-ATEX


Lube Level Maintainer


The LM500-TF-ATEX maintains oil level on any size engine. It also supports installations that require a three-wire, snap-action switch. The form C (three-wire) contact allows a controller/annunciator to be wired as a closed-loop system, resulting in a reliable fault-sensitive circuit.

Refer to LM500 Series Flow Rate Chart for application data. The Murphy LM500-TF-ATEX 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 shut-down the equipment, if supply oil is lost and the equipment continues to use oil. As crankcase oil level drops, the LM500 float also drops and opens the Thumb-Valve™. This allows oil to flow from the supply tank through the LM500 and into the crankcase.

When proper level is achieved in the crankcase, the LM500 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. If the clean oil supply is depleted and oil level continues to fall, the low-level switch will operate an alarm or equipment shutdown.

Estimate available in 40 working days from Italy to Italy.

This product may vary on delivery times, as factories do not guarantee production due to lack of raw materials.

Availability: Available on backorder SKU: 15700837 Categories: , Tags: ,



  • 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
  • Span-switch: SPDT rating 30VAC/VDC@75Ma Max.
  • Wire leads: 18 AWG x 15 in. ± 1 in. (355 mm) length.
  • Condution 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
  • ATEX Operating Temperature: -20°C (-4°F) to 85°C (185°F)
  • Float: 304 Stainless Steel
  • Flow Rates: Refer to LM500 Series Flow Rates chart for application data
  • Dimensions: Overall 6-9/16 inch tall x 6-3/16 inch deep x 3-1/2 deep.
  • For exact dimension:
    • LM500/LM500-TF Shipping Dimensions: 9.5 (W) x 7.5 (D) x 11 in. (H) (241.3 (W) x 190 (D) x 279.4 mm (H))
    • LM500/LM500-TF Shipping Weight: 3 lbs. 13.44 oz (1.74 kg)



LM500 Series Flow Rates


Mounting Brackets with Hardware

In addition to the direct mounting option, Enovation Controls offers two mounting brackets for the LM500. The pipe bracket fits a 7/8 in. (22 mm) diameter pipe (see typical installation). TheUniversal Flange Kitallows various mounting methods.

Typical Installations


How to order

To order the LM500-TF-ATEX use the model number designation diagram below. (Example for Pipe Mount: LM500-TF-PMATEX)


Mounting Brackets with Hardware

In addition to the direct mounting option, Murphy offers two mounting brackets for the LM500-TF-ATEX. The Pipe Bracket Kit fits a 7/8 in. (22 mm) diameter pipe (see typical  nstallation below). The Universal Bracket Mount Kit allows various mounting methods.

For exact dimensions, refer to document “00-02-0745 LM500-TF-ATEX Installation Instructions”.

Additional information

Weight1,74 kg


15700837, LM500-TF-ATEX