EL150K1 Liquid Level Swichgage. The EL150K1 Liquid Level Swichgage? instrument is a combination liquid level gauge and low limit switch; the instrument includes (1) a chamber with pivotal float, (2) an indicating dial with pointer, and (3) a low level contact. When properly installed and maintained, the float operates the pointer which, in turn, both indicates level during normal operation, and closes a switching circuit if the level falls to the low-limit set point.