Two Stage Liquid Level Switches in Housings are designed to shut down machinery or turn on warning devices when the liquid supply approaches a level that is too high or recedes to a level that is too low. They can be wired to flash a warning light, sound a howler, shut down a machine, or signal a computer. This is especially helpful in unattended automated plants. The units can be used with large bearings, gear cases, transformers, circuit breakers, oil tanks, and cutting oil reservoirs on screw machines, along with many other applications.
This Liquid Level Switch is housed in a clear acrylic reservoir with aluminum alloy end plates and Buna-N seals. The unit is mounted on the outside of the reservoir. The lower switch inside the housing should be aligned at the height where low liquid level is a concern. The low level actuation point is measured from the center of the lower 1/2” female NPT inlet. The low level actuation point for water is 2 5/32”, oil is 2 1/4”, and spirits is 2 7/16”. There is 2 3/8” of travel between the lower switch activation point and the upper switch activation point.
The bottom inlet is connected to the reservoir, and the unit is vented into the reservoir’s air supply with the 1/2” female NPT top outlet. When the liquid in the reservoir recedes to the low level or reaches the high level, a magnet carried inside of the stainless steel float actuates a reed switch within the central pipe.
The total height of the housing is 8 5/8”. The distance between center of the inlet and outlet is 6 5/8”. There are (2) 3/8”-24 threaded mounting holes. This unit tolerates up to 125 PSI and temperatures up to 170° F.
For best results use the switch with Oil Rite relay A3154. If the switch is used without the suggested Oil-Rite relay, be sure to keep the switch load within the resistive load rating, as follows:
For additional installation, maintenance, and electrical information, reference the “Liquid Level Switches” document located on the right hand side of this page.