From inside (document excerpt):
58MXA 4-Way Multipoise Fixed-Capacity Direct-Vent Condensing Gas Furnace Visit www.carrier.com Service and Maintenance Instructions For Sizes 040-140, Series 170 FIRE OR EXPLOSION HAZARD Failure to follow this warning could cause corrosion of heat exchanger, fire, personal injury, or death. Never store anything on, near, or in contact with the furnace, such as: 1. Spray or aerosol cans, rags, brooms, dust mops, vacuum cleaners, or other cleaning tools.
2. Soap powders, bleaches, waxes or other cleaning compounds, plastic or plastic containers, gasoline, kerosene, cigarette lighter fluid, dry cleaning fluids, or other volatile fluids. 3. Paint thinners and other painting compounds, paper bags, or other paper products. TABLE OF CONTENTS SAFETY CONSIDERATIONS .1 GENERAL 2 ELECTROSTATIC DISCHARGE (ESD) PRECAUTIONS 2 ELECTRICAL SHOCK, FIRE, OR EXPLOSION HAZARD Failure to follow safety warnings exactly could result in dangerous operation, serious injury, death, or property damage. Improper servicing could result in dangerous operation, serious injury, death, or property damage. – Before servicing, disconnect all electrical power to furnace. – When servicing controls, label all wires prior to disconnecting. Reconnect wires correctly. – Verify proper operation after servicing. CARE AND MAINTENANCE .3 Cleaning and/or Replacing Air Filter .3 Blower Motor and Wheel Maintenance .4 Cleaning Burners 5 Cleaning Heat Exchangers 5 Primary Heat Exchangers 5 Secondary Heat Exchangers 6 Flushing Collector Box and Drainage System 6 Servicing Hot Surface Igniter .8 Electrical Controls and Wiring .8 Checking Heat Tape Operation (If Applicable) 9 Winterizing 9 WIRING DIAGRAM .9 TROUBLESHOOTING .9 Status Codes 9 Component Tests 11 SAFETY CONSIDERATIONS Recognize safety information. This is the safety-alert symbol. When you see this symbol on the furnace and in instructions or manuals, be alert to the potential for personal injury. Understand the signal words DANGER, WARNING, CAUTION, and NOTE. These words are used with the safety-alert symbol. DANGER identifies the most serious hazards which will result in severe personal injury or death. WARNING signifies hazards which could result in personal injury or death. CAUTION is used to identify unsafe practices which may result in minor personal injury or product and property damage.