Took it all apart, cleaned, and checked the thermocouple. It checked fine. Reassembled, and lit it up. This time, I was very quiet and I could hear a small amount of gas going through after releasing the pilot and waiting, then setting control to high. There was a very small amout of heat coming off the bottom of the unit. When I listened closely, low, medium, or high didn't make any difference. I'm pretty sure there is a little bit of gas coming out, and it must be burning because I don't smell any raw propane. So now I' thinking control valve or plugged hole where the gas comes out. When I had it apart, I see that the gas comes out at the top of the unit and then just falls over the catalytic material and burns like that? I could put my hand right on the grill, and it wasn't too hot, just a bit warm at the bottom.