Rheem Manufacturing Co., Air Conditioning Division introduced the Rheem Prestige Series® and Ruud Ultra Series®, which are rated up to 16.8 SEER and use R-22 refrigerant. Both are equipped with an Emerson® Climate Technologies Comfort Alert™ on-board diagnostics system that detects system and electrical problems. The company said an R-410A model will be available in the fourth quarter of 2004.