Presto HeatDish Compact Heater "heat dish buzzing turn" Questions

...heat dish plusRise heater make a noise every time turn on, .Turn on and of every 10 seconds? We have one in our office where our entry is pretty close to teh main door. It used to buzz all the time ...

...Heat Dish compact parabolic heater purchased at Costco. It heats well in one direction when it's on but has a problem with the temperature control being on all the time or off and not heating. For a ...