Hi all! I'm new here, so excuse me if I come off as a complete boob. I have a HeatNGlo direct vent gas fireplace with a pilot problem. Its strong and smooth with the glass removed, but shudders and is noisy with the glass on. Usually, goes out within an hour or two. I recently replaced the entire pilot assembly (thermocouple, thermopile, ignitor) because the original ignitor was fried and the pilot was orange and smoking up the logs / glass and no amount of cleaning the orifice would improve it. After installing the new assembly, the pilot is strong, quiet and blue as it should be. Once I reinstall the glass, it gets noisy and flutters before going out. All was well before, but I checked the venting just to be sure and its clear on both the inner and outer tubes. Its worked fine for 15 years, but I just felt these parts were due for replacement and they're the correct parts for the unit. Anyone have any ideas? Whats changed to cause this? Thanks in advance Barney.