Carrier 50SZ Series Installation, Start-up And Service Instructions Manual

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Contents

Step 5—Select and Install DuctworkThe design and installation of the duct system must be inaccordance with the standards of the NFPA for installation ofnon-residence type air conditioning and ventilating systems, NFPA90A or residence type, NFPA 90B and/or local codes andordinances.Select and size ductwork, supply-air registers, and return air grillesaccording to ASHRAE (American Society of Heating, Refrigera-tion, and Air Conditioning Engineers) recommendations.The unit has duct flanges on the supply- and return-air openings onthe side of the unit.When designing and installing ductwork, consider the following:For vertical supply and return units, tools or parts could dropinto ductwork and cause serious injury or death. Install a 90degree turn in the return ductwork between the unit and theconditioned space. If a 90 degree elbow cannot be installed,then a grille of sufficient strength and density should beinstalled to prevent objects from falling into the conditionedspace. Units with electric heaters require 90 degree elbow insupply duct.1. All units should have field-supplied filters or accessory filterrack installed in the return-air side of the unit. Recommendedsizes for filters are shown in Table 1.2. Avoid abrupt duct size increases and reductions. Abruptchange in duct size adversely affects air performance.IMPORTANT: Use flexible connectors between ductwork andunit to prevent transmission of vibration. Use suitable gaskets toensure weather tight and airtight seal. When electric heat isinstalled, use fireproof canvas (or similar heat resistant material)connector between ductwork and unit discharge connection. Ifflexible duct is used, insert a sheet metal sleeve inside duct. Heatresistant duct connector (or sheet metal sleeve) must extend 24-in.from electric heater element.3. Size ductwork for cooling air quantity (cfm). The minimumair quantity for proper electric heater operation is listed inTable 2. Heater limit switches may trip at air quantities belowthose recommended.4. Seal, insulate, and weatherproof all external ductwork. Seal,insulate and cover with a vapor barrier all ductwork passingthrough conditioned spaces. Follow latest Sheet Metal and AirConditioning Contractors National Association (SMACNA)and Air Conditioning Contractors Association (ACCA) mini-mum installation standards for residential heating and airconditioning systems.5. Secure all ducts to building structure. Flash, weatherproof, andvibration-isolate duct openings in wall or roof according togood construction practices.CONVERTING HORIZONTAL DISCHARGE UNITS TODOWNFLOW (VERTICAL) DISCHARGE UNITSELECTRICAL SHOCK HAZARDFailure to follow this warning could result in personal injuryor death.Before performing service or maintenance operations onsystem, turn off main power to unit and install lockout tag.Turn off accessory heater power switch if applicable.1. Open all electrical disconnects and install lockout tag beforestarting any service work.2. Remove side duct covers to access bottom return and supplyknock outs.NOTE: These panels are held in place with tabs similar to anelectrical knockout.3. Use a screwdriver and hammer to remove the panels in thebottom of the composite unit base.Fig. 4—Corner Weights (in Pounds)CORNER # 50SD024 030 036 042 048 0601 69 74 87 93 97 992 53 57 68 72 74 763 83 88 104 111 116 1194 138 147 174 184 193 198TOTAL WEIGHT 343 366 433 460 480 492C000711 24 3xy5