SS3 water level switch is used for HVAC system to detect the condensate overflow, it detects clogged air conditioning condensate drains and shuts off the system to prevent the overflowing water damage to floors, walls and ceilings. This easy to install with stainless steel self-hold bracket, and easy for removing and cleaning. The switch can be connected to either the VCC or thermostat wires, it is NC type(normally closed) switch: When there is no water overflowing, the floater stays on the bottom of the switch, the switch is close loop, and output ON signal; When there is water overflowing, the floater is raised by buoyancy and trigger the switch to open loop, and output OFF signal to shut-off the device.