Carrier WeatherMaker 48FC04-07 Installation Instructions Manual

9Fig. 4 — Unit Leveling TolerancesInstall insulation, cant strips, roofing felt, and counterflashing as shown. Ductwork must be attached to curb andnot to the unit. The accessory thru-the-base power and gasconnection package must be installed before the unit is set onthe roof curb. If field-installed thru-the-roof curb gas connec-tions are desired, use factory-supplied 1 /2 -in. pipe couplingand gas plate assembly to mount the thru-the-roof curb con-nection to the roof curb. Gas connections and power connec-tions to the unit must be field-installed after the unit is in-stalled on the roof curb.If electric and control wiring is to be routed through thebasepan, attach the accessory thru-the-base service connec-tions to the basepan in accordance with the accessory installa-tion instructions.SLAB MOUNT (HORIZONTAL UNITS ONLY)Provide a level concrete slab that extends a minimum of6 in. (150 mm) beyond unit cabinet. Install a gravel apron infront of condenser coil air inlet to prevent grass and foliagefrom obstructing airflow.NOTE: Horizontal units may be installed on a roof curb if re-quired.ALTERNATE UNIT SUPPORT (IN LIEU OF CURB ORSLAB MOUNT)A non-combustible sleeper rail can be used in the unit curbsupport area. If sleeper rails cannot be used, support the longsides of the unit with a minimum of 3 equally spaced 4-in. x4-in. (102 mm x 102 mm) pads on each side.Step 5 — Field Fabricate DuctworkCabinet return-air static pressure (a negative condition)shall not exceed 0.35 in. wg (87 Pa) with economizer or 0.45in. wg (112 Pa) without economizer.For vertical ducted applications, secure all ducts to roofcurb and building structure. Do not connect ductwork to unit.Fabricate supply ductwork so that the cross sectional di-mensions are equal to or greater than the unit supply ductopening dimensions for the first 18 in. (458 mm) of ductlength from the unit basepan.Insulate and weatherproof all external ductwork, joints,and roof openings with counter flashing and mastic in accor-dance with applicable codes.Ducts passing through unconditioned spaces must be insu-lated and covered with a vapor barrier.If a plenum return is used on a vertical unit, the returnshould be ducted through the roof deck to comply with appli-cable fire codes.A minimum clearance is not required around ductwork.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. Rig-ging materials under unit (cardboard or wood) must be re-moved PRIOR to placing the unit on the roof curb. Level byusing unit frame as a reference. See Table 2 and Fig. 5 for ad-ditional information.Lifting holes are provided in base rails as shown in Fig. 5.Refer to rigging instructions on unit.Rigging materials under unit (cardboard or wood to pre-vent basepan damage) must be removed PRIOR to placingthe unit on the roof curb.When using the standard side drain connection, ensure thered plug in the alternate bottom connection is tight. Do thisbefore setting the unit in place. The red drain plug an be tight-ened with a 1 /2-in. square socket drive extension. For furtherdetails, see “Step 12 — Install External Condensate Trap andLine” on page 15.Before setting the unit onto the curb, recheck gasketing oncurb.POSITIONING ON CURBPosition unit on roof curb so that the following clearancesare maintained: 1 /4 in. (6.4 mm) clearance between the roofcurb and the base rail inside the front and rear, 0.0 in. clear-ance between the roof curb and the base rail inside on theduct end of the unit. This will result in the distance betweenthe roof curb and the base rail inside on the condenser end ofthe unit being approximately 1/4 in. (6.4 mm).Although unit is weatherproof, guard against water fromhigher level runoff and overhangs.Flue vent discharge must have a minimum horizontalclearance of 4 ft (1220 mm) from electric and gas meters, gasregulators, and gas relief equipment. Minimum distance be-tween unit and other electrically live parts is 48 inches(1220 mm).ABCMAXIMUM ALLOWABLEDIFFERENCE IN. (MM)A-B B-C A-C0.5 (13) 1.0 (25) 1.0 (25)CAUTIONFailure to follow this caution may result in damage to roof-ing materials.Membrane roofs can be cut by sharp sheet metal edges. Becareful when placing any sheet metal parts on such roof.CAUTIONFailure to follow this caution may result in injury or equip-ment damage.All panels must be in place when rigging. Unit is notdesigned for handling by fork truck when panels or pack-aging are removed.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 loweringthe crate.CAUTIONFailure 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 panels or pack-aging are removed.