Abstract:
The present invention provides for a humidistat which can be connected to a humidifier through a thermostat and its existing wiring. The thermostat has a plurality of output leads for a heating signal, a fan signal and/or a cooling signal. The humidistat includes a first input for receiving the heating signal from the thermostat, a sensor associated with the first input for sensing the relative humidity of the air in the enclosed volume, a second input for receiving the cooling signal from the thermostat, and a first switch with a heating position and a cooling position for switching between the first and second inputs, respectively, and an interface module for selectively energizing either a humidifier when the first switch is in the heating position or a cooling system when the first switch is in the cooling position. The interface module can further include a second switch for switching between the humidification position and the cooling position and a timing device for timing a predetermined period of time after receiving the cooling signal to delay switching the second switch to the cooling position.