My fireplace is gas operated. Do i need to have the fluke open?

When i use the gas in my fireplace and the fluke is open it makes no heat. When the fluke is closed it warms the entire house. Is it dangerous to us to have the gas fire on with the fluke closed? It really does send all the heat out the chimney with the fluke open. Any help or knowledge on the subject would be greatly appreciated... Thank you to those of you who answer this question.