My air conditioner has been working fine when I turned the air on, now that it is kind of cool outside I turned the heater on. I just moved into this house and I do not know how to work the thermstat and ever since I turned the heat on, I can still hear the fan on. The conditioner is turned off but I can still hear it on, so my question is how do I turn it off? It has different periods... ex. Period 1 period 2 period 3 and period 4, does that have anything to do with it?