I just bought a house and it came with a Majestic gas fireplace. There were no manuals left behind for this fireplace and can not tell what the model number or series is. I only know that it's a Majestic brand because on the bottom left corner of the glass it is shown there. This particular unit is connected to a thermostat for control and to help with heating of the home. My issue is that once I get the pilot lit and then the fireplace gets lit it will stay on for a while. After about 20 or so seconds it will click itself off and the pilot light will also turn off. How can I get this to stay lit?