JLC · AUGUST 1989 Getting the Kinks Out of High- Efficiency Furnaces A furnace technician tests the controls on a condensing furnace during an annual tuneup. Special training and knowledge of electronics is needed. The New Generation of Gas Furnaces Won't Fall to Rust, but They Will Need Extra Maintenance by Frank Green The hvac industry reacted quickly to the "energy crunch" of the mid-1970s by making major changes in natural-gas furnace design. Perhaps they acted too quickly, becuase the dramatic new designs brought with them design errors, recalls, and a host of complaints. Contractors today have reason to be concerned abut product reliability. Most major manufacturers, however, have gone through several generations of design. With nearly a decade of field experience