Carrier Owners Manual - Enlarge page 1 of 2
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Coupling Box Assembly Kit Cancels: IIK 398A-40-18 IIK 398A-40-30 3-1-92 Installation Instructions Part No. 308593-751, -752, & -753 NOTE: Read the entire instruction before starting the installation. INTRODUCTION This instruction covers installation of Coupling Box Assembly Kit Part No. 308593-751, -752, or -753 in an upflow gas-fired condensing furnace. NOTE: A releasing agent (such as Pam cooking spray or equivalent) and RTV sealant (G.E.
122, 162, or Dow-Corning 738) are required before starting the installation. Do not substitute any other type of RTV sealant. A gasket kit (Part No. 318050-751) may be required to complete this installation. SAFETY CONSIDERATIONS Installation and service of heating equipment can be hazardous due to gas and electrical components. Only trained personnel should install or service heating equipment. 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, and on tags and labels attached to the unit. Follow all safety codes. Wear safety glasses and work gloves. Have a fire extinguisher available. 7. Remove screws securing main control box to blower shelf. Lay control box in bottom of furnace. 8. Loosen hose clamp and remove drain tube from bottom of inducer housing (lower side of blower shelf). 9. Loosen hose clamp on pressure tube (from plastic tee) at pressure switch. Remove tube from pressure switch. 10. Loosen hose clamp on tube (from pressure switch) at collector box. Remove tube from collector box. 11. Loosen hose clamp on drain tube (from inducer outlet box) at collector box. Remove tube from collector box. 12. Remove and discard mounting screws securing inducer assembly (motor, pressure switch, inducer housing, and inducer outlet box). Remove assembly from furnace. Step 2–Removal of Coupling Box 1. Remove screws securing coupling box to cell panel and condensing heat exchanger. Do not remove screws through insulation. 2. Using a screwdriver blade, break seal between top flange of coupling box and cell panel. 3. Remove coupling box assembly from furnace. Step 3–Installation of New Coupling Box 1. Clean old sealant from cell panel and end panel of condensing heat exchanger. 2. Apply releasing agent to flange surface of new coupling box where sealant is to be applied. (See Fig. 1.) Before beginning any installation or modification, be sure the main electrical disconnect switch is in the OFF position. Electrical shock can cause personal injury or death. DESCRIPTION AND USAGE This kit can be utilized to restore units having a coupling box assembly requiring replacement. This kit contains the following items: Coupling box assembly Stainless steel screws (in bag) Installation Instructions INSTALLATION Step 1–Removal of Inducer Assembly 1. Turn OFF gas and electrical supplies to unit. 2. Remove control and blower access doors. 3. Loosen hose clamp at vent pipe connection; disconnect vent pipe. Position vent pipe out of way. 4. Disconnect electrical connector(s) from inducer control box (if used). Disconnect pressure switch wiring. 5. Disconnect inducer motor leads. 6. Disconnect electrical connector from main control box at blower shelf. (1) (5) (1) A83158 Fig. 1–Coupling Box Sealant Application Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations. Book 1 4 PC 101 Catalog No.