From inside (document excerpt):
Product Data ® 58MXA Deluxe 4-Way Multipoise Fixed-Capacity Condensing Gas Furnace Series 121 Input Capacities: 40,000 thru 120,000 Btuh 4-Way Multipoise Design Allows More Applications. The model 58MXA is a must for your product line. This high-efficiency furnace allows more applications with its reliable 4-way multipoise design. The model 58MXA is available in 11 heat/airflow combinations and with the 4-way multipoise design can be installed in upflow, downflow, or horizontal positions covering up to 44 different applications.
The 58MXA can be installed in a manufactured (mobile) home when the optional kit is used. The furnace is factory configured for upflow application. This versatile unit utilizes hot surface ignition (HSI) which ignites the burners directly. HSI eliminates gas waste that typical continuous-pilot designs can bring. Hot surface ignition provides reliable start-up and operation. Take a look at the control center on model 58MXA. Control of ignition, inducer, and blower operation is all handled in 1 central printed circuit board. The status indicator on the control signals when a fault has occurred and identifies where the problem is. This, along with the component test feature, makes the 58MXA one of the easiest gas furnaces to troubleshoot. High efficiency is achieved by maximizing heat transfer. The model 58MXA uses 100% outdoor air for combustion in a sealed-combustion system. The result is energy-saving efficiency, 92% Annual Fuel Utilization Efficiency (AFUE), and reduced operational noise. The model 58MXA is 1 of the quietest furnaces in the industry. A unique feature of this unit is the patented polypropylene-laminated heat exchanger. This secondary heat exchanger ensures that all available heat ® ® ·· ·· ·· U L T R 1995 Carrier Corporation Form 58MXA-3PD Thi d t t d ith F M k 404 is properly transferred to the airstream and throughout the home. Using the exclusive flow-through design, the secondary heat exchanger reduces the pressure drop in the furnace which leads to lower electrical usage, an important part of this unit’s efficiency. Carrier heat exchangers are backed by a Limited Lifetime Warranty.* When we put it all together, the model 58MXA combines quality and design to bring high efficiency and comfort.