VENT STACK'^EXTENSIONASSEMBLEDA76308Figure 6—Vent Cap AssemblyWARNING: Never use a match or other open flame.CAUTION: A backup wrench should be used on the connect- iing end of the shut-off cock to avoid strain on, or distortion ;;of^ the gas control piping.IV DUCT CONNECTIONSThe ductwork may be screwed or bolted to the unit flangewith suitable gaskets to insure an airtight seal. Be suremetal overlaps the flange on the unit. See Figures 8, 9, and10 for illustrations of typical installations.CAUTION; When drilling duct flange fastening holes, usecare to avoid puncturing evaporator coil. Properly insulateand waterproof all ductwork external of the structure.NOTE: When installing the accessory plenum, unitizedcurb, flexible ducts, or other rooftop system accessories, seeinstallation instructions for that specific accessory.All openings in the structure must be properly flashed andvibration-isolated in accordance with local codes and goodbuilding practices. Provide supply and return ductwork withan approved vibration eliminator.NOTE: External filter must be supplied and installed whereeasily accessible for service. For recommended filter area,see Table I.V, Electrical ConnectionsAll electrical connections must be made in accordance withNational Electrical Code and local electrical codes govern¬ing such wiring.The unit must be electrically grounded in accordance withthe National Electrical Code, ANSI Cl-1975, when installedif an external electrical source is utilized.WARNING: The unit cabinet must have an uninterruptedor unbroken electrical ground to minimize personal injury ifan electrical fault should occur. This may consist of electri¬cal wire or approved conduit when installed in accordancewith existing electrical codes.COOLING RELAYHEATING RELAYMOLEX SPEEDCONNECTOREVAPORATORRUN CAPACITORBALLASTTUBECOMPRESSORSTART CAPACITOR-^-INCH PIPE PLUGoGAS VALVETRANSFORMERCOMPRESSORCONTACTORGROUND LUGCOMPRESSOR RUNCAPACITORCONDENSER RUNCAPACITORCOMPRESSORSTART RELAYLOW-VOLTAGE LEADSGAS INLETBURNERSGAS MANIFOLDA76309Figure 7—Partial Left-Side View with Control Access Door Removed-5-