Carrier 50KC*A/B06 Series Installation Instructions Manual

9Step 5 — Field Fabricate DuctworkCabinet return-air static pressure (a negative condition) shallnot exceed 0.35-in. wg (87 Pa) with economizer or 0.4-in. wg(112 Pa) without economizer.For vertical ducted applications, secure all ducts to roof curband building structure. Do not connect ductwork to unit.Fabricate supply ductwork so that the cross sectional dimen-sions are equal to or greater than the unit supply duct openingdimensions for the first 18-in. (458 mm) of duct length fromthe unit basepan.Insulate and weatherproof all external ductwork, joints, androof openings with counter flashing and mastic in accordancewith applicable codes.Ducts passing through unconditioned spaces must be insulat-ed and covered with a vapor barrier.If a plenum return is used on a vertical unit, the return shouldbe ducted through the roof deck to comply with applicablefire codes.FOR UNITS WITH ACCESSORY ELECTRIC HEATERSAll installations require a minimum clearance to combustiblesurfaces of 1-in. (25 mm) from duct for the first 12-in. (305mm) away from unit.Outlet grilles must not lie directly below unit discharge.NOTE: A 90 degree elbow must be provided in the ductworkto comply with UL (Underwriters Laboratories) code for usewith electric heat.Step 6 — Rig and Place UnitKeep unit upright and do not drop. Spreader bars are re-quired. Rollers may be used to move unit across a roof. Levelby using unit frame as a reference. See Table 2 and Fig. 6 foradditional information.Lifting holes are provided in base rails as shown in Fig. 6.Refer to rigging instructions on unit.Before setting the unit onto the curb, recheck gasketing oncurb.Rigging materials under unit (cardboard or wood to preventbase pan damage) must be removed PRIOR to placing theunit on the roof curb.When using the standard side drain connection, ensure the redplug in the alternate bottom connection is tight. Do this be-fore setting the unit in place. The red drain pan plug can betightened with a 1/ 2-in. square socket drive extension. For fur-ther details see “Step 10 — Install External Condensate Trapand Line” on page 12.POSITIONING ON CURBPosition unit on roof curb so that the following clearances aremaintained: 1/4-in. (6.4 mm) clearance between the roof curband the base rail inside the front and rear, 0.0-in. clearancebetween the roof curb and the base rail inside on the duct endof the unit. This will result in the distance between the roofcurb and the base rail inside on the condenser end of the unitbeing approximately 1/4 -in. (6.4 mm).Although unit is weatherproof, guard against water fromhigher level runoff and overhangs.After unit is in position, remove rigging skids and shippingmaterials.CAUTIONPROPERTY DAMAGE HAZARDFailure to follow this caution may result in damage to roofingmaterials.Membrane roofs can be cut by sharp sheet metal edges. Becareful when placing any sheet metal parts on such roof.WARNINGPERSONAL INJURY HAZARDFailure to follow this warning could cause personal injury.For vertical supply and return units, tools or parts could dropinto ductwork and cause an injury. Install a 90 degree turn inthe return ductwork between the unit and the conditionedspace. If a 90 degree elbow cannot be installed, then a grilleof sufficient strength and density should be installed toprevent objects from falling into the conditioned space. Dueto electric heater, supply duct will require 90 degree elbow.CAUTIONUNIT DAMAGE HAZARDFailure to follow this caution may result in equipmentdamage.All panels must be in place when rigging. Unit is notdesigned for handling by fork truck when packaging isremoved.If using top crate as spreader bar, once unit is set, carefullylower wooden crate off building roof top to ground. Ensurethat no people or obstructions are below prior to lowering thecrate.