Carrier 58DXT Operating Instructions Manual

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

Contents

Carrier 58DXT Operating Instructions Manual Manual pdf 6 page image

b. If combustion air is taken from outdoors through 2 hori-zontal ducts, the openings and ducts MUST have at least 1sq in. of free area per 2000 Btuh of total input for allequipment within the confined space. (See Fig. 4 and Table2.)c. If combustion air is taken from outdoors through a singleopening or duct (horizontal or vertical) commencing within12 in. of the top of the confined space, opening and ductMUST have at least 1 sq in. of free area per 3000 Btuh ofthe total input for all equipment within the confined spaceand not less than the sum of the areas of all vent connectorsin the confined space. (See Fig. 4 and Table 2.) Equipmentclearances to the structure shall be at least 1 in. from thesides and back and 6 in. from the front of the appliances.When ducts are used, they must be of the same cross-sectional areaas the free area of the openings to which they connect. Theminimum dimension of ducts must not be less than 3 in. (See Fig.4.)Step 3—Air DuctsGENERAL REQUIREMENTSThe duct system should be designed and sized according toaccepted national standards such as those published by: AirConditioning Contractors Association (ACCA), Sheet Metal andAir Conditioning Contractors National Association (SMACNA) orAmerican Society of Heating, Refrigerating and Air ConditioningEngineers (ASHRAE) or consult factory The Air Systems DesignGuidelines reference tables available from your local distributor.The duct system should be sized to handle the required systemdesign CFM at the design static pressure.When a furnace is installed so that the supply ducts carry air toareas outside the space containing the furnace, the return air mustalso be handled by a duct(s) sealed to the furnace casing andterminating outside the space containing the furnace.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.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 CONNECTIONSConnect supply-air duct to supply-air opening on furnace. Thesupply-air duct attachment must ONLY be connected to fur-nace supply/outlet or air conditioning coil casing (when used),when installed on non-combustible material. When installed oncombustible material, supply-air duct attachment must ONLYbe connected to an accessory subbase or factory approved airconditioning coil casing. DO NOT cut main furnace casing toattach supply side air duct, humidifier, or other accessories. Allaccessories MUST be connected external to furnace maincasing.RETURN AIR CONNECTIONSThe return-air duct must be connected to return-air openingprovided as shown in Fig. 1. DO NOT cut into casing sides orback to attach any portion of return-air duct. Bypass humidifierconnections should be made at ductwork or coil casing sidesexterior to furnace.Step 4—Supply-Air Plenum InstallationDOWNFLOW INSTALLATIONNOTE: This furnace is approved for use on combustible flooringwhen manufacturer’s accessory floor base Part No.KGASB0201ALL is used. Manufacturer’s accessory floor base isnot required when this furnace is installed on manufacturer’s CoilAssembly Part No. CD5 or CK5, or Coil Box Part No. KCAKC isused.1. Determine application being installed from Table 3.2. Construct hole in floor per dimensions specified in Table 3and Fig. 5.3. Construct plenum to dimensions specified in Table 3.4. If downflow subbase (KGASB) is used, install as shown inFig. 6.If coil assembly CD5, CK5, or Coil Box KCAKC is used,install as shown in Fig. 7.INSTALLATION ON COMBUSTIBLE FLOOR1. Cut and frame hole in floor per dimensions in InstallationInstructions packaged with downflow subbase.2. When completed, downflow subbase, plenum, and furnace (orcoil casing when used) should be installed as shown in Fig. 6.Table 2—Minimum Free Area Of Combustion Air Opening58DXTFURNACEHIGH-FIREINPUT(BTUH)AIR FROM INDOORUNCONFINEDSPACEOUTDOOR AIR THROUGHVERTICAL DUCTSOUTDOOR AIR THROUGHHORIZONTAL DUCTSOUTDOOR AIR THROUGHSINGLE DUCTFree Areaof Opening(Sq In.)Free Area ofOpening and Duct(Sq In.)RoundPipe(In. Dia)Free Area ofOpening and Duct(Sq In.)RoundPipe(In. Dia)Free Area ofOpening and Duct(Sq In.)RoundPipe(In. Dia)63,000 100 15.8 5 31.5 7 21.0 684,000 100 21.0 6 42.0 8 28.0 6105,000 105 26.3 6 52.5 9 35.0 76→