From inside (document excerpt):
58CVA/58CVX Variable-Speed, 4-Way Multipoise Gas Furnace Installation, Start-up, Operating, and Service and Maintenance Instructions -Series 100 THE WEATHERMAKER® 8000VS GAS FURNACE The 58CVA/CVX Variable-Speed, 4-way Multipoise Gas Furnaces offer unmatched comfort with ComfortHeat Technology and IdealHumidity in an 80% AFUE gas furnace. You get all the benefits of a ComfortHeat Technology furnace: reduced drafts, reduced sound levels, longer, more gentle cycles, less temperature swings between cycles, and less temperature differences between rooms.
With the variable speed blower motor, homeowners can now economically run constant fan to help eliminate temperature differences throughout the house and to get better indoor air quality. This IdealHumidity furnace also increases comfort in the summer by wringing out extra humidity when needed. The 58CVA furnaces are approved for use with natural or propane gas, and the 58CVX is approved for use in low Nox Air Quality Management Districts. STANDARD FEATURES · ComfortHeat Technology Intelligent microprocessor control Two-stage heating with single-stage thermostat Very low operating sound through low-stage operation and QuieTech noise reduction system Integral part of the IdealHumidity System Maximum dehumidification selection for summer time cooling Full IdealHumidity benefits including “Super Dehumidify ” Variable-speed blower motor Super-low electrical use, up to 80 percent less than standard models Increased SEER ratings for AC and HP systems Perfectly matches CFM to cooling system at all static points Media Filter Cabinet Included Microprocessor based “smart ” control center Automatically adjusts heating stage times to meet demand Adjustable heating air temperature rise ComfortFan – Constant fan speed selectable from thermostat Up to 12 cooling airflow selections with a wide range of capability LED diagnostics and self test feature Stores fault codes during power outages Optional laptop and handheld PDA diagnostic software 4-way Multipoise furnace, 13 vent applications Shorter in height only 33 ” tall Hot surface ignition (HSI) Draft safeguard switch to ensure proper furnace venting Insulated blower compartment Heat pump compatible All models are Chimney Friendly when used with accessory vent kit Residential installations eligible for consumer financing through the Retail Credit Program LIMITED WARRANTY 20-year warranty on “Super STM ” heat exchanger 5-year parts warranty on all other components 7-02 Catalog No: 535-80057 Form No. 58CV-1SI Variable Speed Induced-Combustion Deluxe 4-Way Multipoise Furnace Cancels: New II 315A-70-1 7-02 Installation, Start-up, Operating, and Service and Maintenance Instructions Series 100/A NOTE: Read the entire instruction manual before starting the installation. TABLE OF CONTENTS SAFETY CONSIDERATIONS .