The Asurity BG-101 protects the HVAC circuit by eliminating intermittent condensate tripping with latching snap action. The switch attaches to the side of the HVAC secondary drain pan, clamps in place for a secure hold, and can be adjusted for the deepest pans on the market. Once the latch mechanism is triggered, the power to your HVAC air handler will be interrupted, and the system will shut down. The BG-101 will stay latched and the system will remain off, even if the water has receded, until manually reset. This eliminates any intermittent condensate tripping, minimizing wear on systems and making diagnoses easier. More than likely you have a drain pan switch installed already but it is likely to be a) old and b) not a latching type. A non-latching type will certainly turn off the air-handler when the drain pan fills with water BUT . . . as soon as that water drains away or evaporates the system will be restarted, doomed to contine to fill up the drain pan with water again. The latching type switches will stop this happening and allow the owner to make the neccessary repairs immedately upon discovery. This drastically improves the life of all components and minimises the flood risk significantly. Aquaguard