Abstract: An alarm device that connects to a circuit using two wires and is actuated when a switch changes the status of the circuit from a normally closed circuit condition to open circuit condition. The alarm device includes a PC board with an electronic buzzer, an electronic signal transmitter and/or a visual indicator, such as a flashing LED, all of which may be enclosed within a case. The circuitry of the alarm device is non-polarized, thereby allowing the two wires to be connected to either terminal connection point in the circuit.

Abstract: A condensate overflow safety switch that can be used with an air handling system is disclosed. The air-cooling system includes a drain pan for collecting liquid condensed on the evaporator coils. The drain pan is fluidwise connected to the safety switch that is in turn electrically connected to a circuit of the air handling system. To reduce the probability of an overflow from the drain pan arising from an occlusion to water liquid draining from the drain pan, an annular float is mounted about a tube in which is sealed a reed switch electrically connected to a circuit of the air handling system or to an alarm circuit. The float containing an annular magnet ascends or descends based on the level of water liquid within the structure.

Abstract: A safety switch that can be used with an air handling system is disclosed. The air-cooling system includes a drain pan for collecting liquid condensed on the evaporator coils. The pan is fluidwise connected to a T- or L-shaped tubular structure, installable at any slope from horizontal to vertical, in which the switch is mounted and the switch is electrically connected to a circuit of the system, a power circuit or an alarm circuit. The switch has an annular float containing an annular magnet mounted about a tube in which is sealed a reed switch. The float ascends or descends based on the level of liquid within the tubular structure. Dependent upon a predetermined level of liquid within the tubular structure the float will move along the tube to open or close the reed switch to either disrupt operation of the air handling system or operate an alarm circuit.