An 80-percent AFUE gas furnace is available in 16 sizes, from 40,000 to 140,000 Btuh, with blower drives to handle 2 to 6 tons. The multiposition furnace has the Sparklite ignition system, which uses a continuous spark igniter that lights the main burner. The Sparklite system features a diagnostic light and a flame light, which will indicate the type of problem should one occur during the ignition sequence. The furnace is 31-5/8 inches high and is ready for 13-SEER coils, the company says. The unit has a four-speed blower. Each furnace has a five-year parts warranty and 20-year heat exchanger warranty.