From inside (document excerpt):
Coupling Box Kit Cancels: IIK 350M-35-5 IIK 340M-40-5 6-15-94 Installation Instructions Part No. 320721-761, -762, -763, -764, -765, and -766 NOTE: Read the entire instruction manual before starting the installation. SAFETY CONSIDERATIONS Installing and servicing heating equipment can be hazardous due to gas and electrical components. Only trained personnel should install or service heating equipment.
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Untrained personnel can perform basic maintenance functions such as cleaning and replacing filters. All other operations should be performed by trained service personnel. When working on heating equipment, observe precautions in the literature, on tags, and on labels attached to the unit. Follow all safety codes. Wear safety glasses and work gloves. Have a fire extinguisher available 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, and CAUTION. 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 a hazard which could result in personal injury or death. CAUTION is used to identify unsafe practices which would result in minor personal injury or product and property damage. INSTALLATION Table 1–Kit Usage UNIT KIT PART NO. 340MAV 350MAV 490AAV 024040 036040 036060 048060 036080 048080 060080 048100 060100 060120 — 355MAV — 042060 042080 060100 — 042040 58MCA 58MXA 040-08 040-12 060-12 060-16 080-12 080-16 080-20 100-16 100-20 120-20 — 58MVP — 060-14 080-14 100-20 — 040-14 320721-761 320721-762 320721-763 320721-764 320721-765 320721-766 Step 1–Remove Whole Cell Panel Assembly See Fig. 1 for furnace component locations. See Fig. 2 for an exploded view of heat system components. 1. Turn off gas and electrical supplies to furnace. 2. Remove furnace door. 3. Remove blower access panel. 4. Disconnect field power wires from J-box. Turn off gas and electrical supplies to unit before beginning any installation or modification. Follow operating instructions on label attached to furnace. Failure to follow this warning could result in electrical shock, fire, personal injury, or death. INTRODUCTION This instruction covers installation of the coupling box kit Part No. 320721-761, -762, -763, -764, -765, and -766 in multipoise, 40-in. tall, condensing gas furnaces. NOTE: A releasing agent (PAM cooking spray or equivalent, must not contain corn or canola oil, aromatic or halogenated hydrocarbons) and RTV sealant (G.E. 162 or Dow-Corning 738) are required before starting installation. DO NOT substitute any other type of RTV sealant. DESCRIPTION AND USAGE Use this coupling box kit to replace failed coupling box assemblies. This coupling box kit contains the following items: Coupling box assembly Cold spot baffle Screw (No. 8AB X 1/2-in. long hex head) Gasket Installation Instructions 1 1 6 maximum 1 1 5. Remove 2 screws securing J-box. 6. Remove 2 screws securing top filler panel and rotate upwards to remove or allow the whole cell panel to be removed from front of furnace. 7. Disconnect combustion-air intake pipe from intake housing and move pipe out of way. 8. Disconnect gas supply pipe from gas valve using backup wrench. 9. Disconnect vent pipe from inducer housing by loosening clamp. Move pipe out of furnace casing. 10. Remove motor leads, transformer door switch wires, and auxiliary limit switch wires (if present) from control center and pull wires through blower shelf. 11. Remove 2 screws securing blower to blower shelf. 12. Remove 2 screws (next to blower mounting screws) securing blower shelf to cell panel. 13. Remove 3 screws from each side of cell panel. 14. Remove control center by removing screw and pressing tabs inward. 15. Secure control center and J-box to manifold for removal purposes only.