I was having a problem with the 7100 blackening the glass. Didn't matter how hot I got it, the glass stayed black. I learned early on that Hearth and Home does not like to work directly with the owner. Fortunately I had a competent dealer that played the intermediary. They actually sent two technicians and determined that two interior welds were missing allowing air to enter the firebox. They plan to come back and set the welds. The wife is real excited about that. Growing kind of concerned about Quadrafire myself.