A have a 3 year old (2007) Lennox Elite Series AC unit and just found the entire system drained of refrigerant when I went to turn it on for the first time. The Technician told me the problem was the suction line service valve, and said that Lennox doesn't use that style valve any more because it was a bad design and can leak in the winter. He just replaced it with the "new" style...under warranty...but Lennox doesn't cover the labor or refrigerant re-charge (which is probably more than the part). Wondering if anyone else has had problems with this part on a 2007 ish Lennox AC unit. Lennox claims to be unaware of issues with their product, but the AC technicians seem to indicate otherwise.