Carrier 58MTB Installation, Start-up, And Operating Instructions Manual

Also see for 58MTB: User's information manual Owner's manual Service and maintenance instructions

furnace, the return air must also be handled by a duct(s) sealed tothe furnace casing and terminating outside the space containing thefurnace.Secure ductwork with proper fasteners for type of ductwork used.Seal supply- and return-duct connections to furnace with codeapproved tape or duct sealer.Flexible connections should be used between ductwork andfurnace to prevent transmission of vibration. Ductwork passingthrough unconditioned space should be insulated to enhancesystem performance. When air conditioning is used, a vaporbarrier is recommended.Maintain a 1-in. clearance from combustible materials to supply airductwork for a distance of 36 in. horizontally from the furnace. SeeNFPA 90B or local code for further requirements.For a furnace not equipped with a cooling coil, the outlet duct shallbe provided with a removable access panel. This opening shall beaccessible when the furnace is installed and shall be of such a sizethat the heat exchanger can be viewed for possible openings usinglight assistance or a probe can be inserted for sampling the airstream. The cover attachment shall prevent leaks.DUCTWORK ACOUSTICAL TREATMENTMetal duct systems that do not have a 90 degree elbow and 10 ftof main duct to the first branch take-off may require internalacoustical lining. As an alternative, fibrous ductwork may be usedif constructed and installed in accordance with the latest edition ofSMACNA construction standard on fibrous glass ducts. Bothacoustical lining and fibrous ductwork shall comply with NFPA90B as tested by UL Standard 181 for Class 1 Rigid air ducts.SUPPLY AIR CONNECTIONSUpflow FurnacesConnect supply-air duct to 3/4-in. flange on furnace supply-airoutlet. The supply-air duct attachment must ONLY be connectedto furnace supply-/outlet-air duct flanges or air conditioning coilcasing (when used). DO NOT cut main furnace casing to attachsupply side air duct, humidifier, or other accessories. All accesso-ries MUST be connected external to furnace main casing.Downflow FurnacesConnect supply-air duct to supply-air opening on furnace. Thesupply-air duct attachment must ONLY be connected to furnacesupply/outlet or air conditioning coil casing (when used), wheninstalled on non-combustible material. When installed on combus-tible material, supply-air duct attachment must ONLY be con-nected to an accessory subbase or factory approved air condition-ing coil casing. DO NOT cut main furnace casing to attach supplyside air duct, humidifier, or other accessories. All accessoriesMUST be connected external to furnace main casing. Supply airopening duct flanges must be modified per Fig. 24.Horizontal FurnacesConnect supply-air duct to supply air opening on furnace. Thesupply-air duct attachment must ONLY be connected to furnacesupply/outlet or air conditioning coil casing (when used). DO NOTcut main furnace casing to attach supply side air duct, humidifier,or other accessories. All accessories MUST be connected externalto furnace main casing.RETURN AIR CONNECTIONSThe furnace and its return air system shall be designed andinstalled so that negative pressure created by the air circulating fancannot affect another appliance’s combustion air supply or act tomix products of combustion with circulating air, and that the aircirculating fan of the furnace, if installed in an enclosure commu-nicating with another fuel-burning appliance not of the direct-venttype, shall be operable only when any door or panel covering anopening in the furnace fan compartment or in a return air plenumon ducts in the closed position.FIRE HAZARDFailure to follow this warning could result in fire, personalinjury, or death.Never connect return-air ducts to the back of the furnace.Return-air duct connections on furnace side(s) permitted inupflow applications only.Upflow FurnacesThe return-air duct must be connected to bottom, sides (left orright), or a combination of bottom and side(s) of main furnacecasing. Bypass humidifier may be attached into unused side returnair portion of the furnace casing. DO NOT connect any portion ofreturn-air duct to back of furnace casing.Downflow and Horizontal FurnacesThe return-air duct must be connected to return-air openingprovided. DO NOT cut into casing sides or back to attach anyportion of return-air duct. Bypass humidifier connections shouldbe made at ductwork or coil casing sides exterior to furnace.Step 5—Filter ArrangementFIRE, CARBON MONOXIDE AND POISONINGHAZARDFailure to follow this warning could result in fire, personalinjury or death.Never operate unit without a filter or with filter access doorremoved.Fig. 24—Duct FlangesA93029NOYESYESPERFORATEDDISCHARGE DUCTFLANGE210°MIN21