L129 Series

• Check Lube Level Without Shutting Down
• Use On Engines, Pumps, And Compressors
• Combination Indicating Gage with Low and High Limit Switch
• Float Operated


The L129 Series Lube Level SWICHGAGE® is a combination lube level indicating gage and adjustable low and high limit switches. It provides protection against low oil level or high level caused by overfill or fuel or water seepage into the crankcase.

A 6-3/4 inch (171 mm.) deep sight gauge allows you check the condition and level of your oil without shutting down the equipment.

Fingertip adjustable limit contacts, thru 4-7/8 inch (122 mm.) range, make it simple to set high and low limit contacts. If the float touches the high or low limit contact, a normally open circuit will be completed which can activate alarms and/or shutdown the equipment.

There are two models in the L129 Series: L129 and L129CK1. The L129 model is designed for grounded, low voltage electrical systems. It features a one-wire-to-ground electrical circuit. The L129CK1 was designed for applications requiring a three-wire, above ground electrical circuit. It features ungrounded contacts and a conduit hub to protect electrical wiring.

Options are available for both models.

A flow restrictor plug is available that restricts oil flow from the crankcase to the L129 Series switch and vice versa. It is typically used on applications where the engine is not stationary such as marine and mobile equipment.

The L129 Series Lube Level SWICHGAGE®, when properly installed and maintained, can monitor and protect your engines and pumps from improper lubrication level, which can result in extensive damage.



The L129 Series is recommended for engines and pumps with larger crankcase capacity. Although designed primarily for stationary engines, the L129 Series is often used in mobile applications such as marine, rail and some large off-highway trucks.


A two-year limited warranty on materials and workmanship is given with this Murphy product. Details are available on request and are packed with each unit.

* Products covered by this bulletin comply with EMC Council directive 89/336/EEC regarding electromagnetic compatibility except as noted.


Case: Die Cast Aluminum
Lens: Trogamid Nylon
Maximum Working Pressure:  10 psi (68.9 kPa)
Process Connection: 1/2 NPT
Float Material: Brass
Contact Rating: 2 A @ 30 VAC/DC, pilot duty
Shipping Weight: L129: 3 lb. (1.4 kg) L129CK1: 3 lb. 9 oz. (1.6 kg)
Shipping Dimensions (both models):  12 x 4-1/2 x 4-3/4 in. (305 x 114 x 121 mm.)

Wiring Diagrams

These diagrams are shown with the float in the “full” position.


Repair Kits

Specify part number.