Heating Contractors

In our house we have one of the combined cooling heating within a small cabinet air conditioner runs on electricity and heating using natural gas units. While the heater runs this season strong peridicol hear clicking from the unit. It clicks into for a while. It goes out from time to time, even if the home has not reached the desired temperture. After a while we Heat of the house and the click will come and go whenever I want? Some idea? Thank you. In essence – it could be the high temperature switch.