661 series are small electronic control relays for detecting a rising water level. Inside a waterproof enclosure they have a medium-power relay, which are operated by water reaching the trip level, and can be used to control alarms or other equipment. The relay is normally energized when the power supply is switched on and no water is present. When water rises up the side of the box to reach the switching level, the relay drops out. This sequence is failsafe, allowing each model to be used as a water spillage alarm switch or to turn off a valve or stop an air conditioning unit before the water overflows its containment.

FEATURES Small enough to be used in restricted spaces All components encapsulated against moisture ingress Size:  2" (5.0 cm) W, 1.25" (3.1 cm) D,  1.2" (3 cm) H Switch-off height 0.43" (1.1 cm) Switch-on reset 0.31" (0.8 cm) Switching capability 5 amps at 125 VAC Power supply  24 VAC or VDC 1.Watt