The LM300 Series Level Maintainer automatically adds oil to the crankcase as needed to keep the lube level
normal. Most models have built-in switches that will alarm and/or shut down the equipment if the makeup
supply is depleted and engine oil level falls or if overfill conditions exist.
Although these instructions generally refer to an engine application, the LM300 can also be used with
compressors, pumps and coolers. 

NOTE: Friction losses due to piping NOT considered.
Applications: Engines • Compressors • Pumps • Coolers

FEATURES:
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.C. (Normally Closed) in normal operating ranges
CSA certified with switch contacts rated at 10 A at 250 V AC (standard)

Case/Cover: Die cast aluminum
Switch Housing: Aluminum
Approval Rating: All CSA Certified with switch contacts rated at 10 A at 250 VAC (standard)
LM301 through LM305: CSA certified for non-hazardous locations. Enclosure Type 4 certified
LM301-EX through LM305-EX: CSA certified for Class I, Groups C and D; Class II, Groups F and G 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) standard; 1/8 in. (3 mm) available
Wire (switch models): 18 AWG x 13 in. (1.0 mm2 x 330 mm)
Maximum Inlet Pressure (MIP):
30 psi (207 kPa) [2.07 bar] with 1/8 in. (3 mm) orifice
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)
Outlet Connection: 3/4-14 NPT left side, right side and bottom
Crankcase Balance Vent Fitting: 1/2-14 NPT
Mounting: Accepts FW Murphy pipe or universal mounting brackets
Lens: Clear frog eye non-staining, high-impact, high-temperature nylon; UV and heat stabilized
Glass Lens: Available on LM301 and LM301-EX models. Specify GL as part of model number when ordering
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.