Bryant 581A B. Alternate Unit Support, C. Slab Mount Horizontal Units Only, A. Positioning

IMPORTANT: The gasketing of the unit to the roof curb is critical for a watertight seal. Install gasket with the roof curb as shown in Fig. 1. Improperly applied gasket can also result in air leaks and poor unit performance. Do not slide unit to position on roof curb.

B. Alternate Unit Support

When a curb cannot be used, install unit on a noncombusti- ble surface. Support unit with sleepers, using unit curb support area. If sleepers cannot be used, support long sides of unit with a minimum of 3 equally spaced 4-in. x 4-in. pads on each side.

C. Slab Mount (Horizontal Units Only)

Provide a level concrete slab that extends a minimum of 6 in. beyond unit cabinet. Install a gravel apron in front of con- denser coil air inlet to prevent grass and foliage from obstructing airflow.

NOTE: Horizontal units may be installed on a roof curb if required.

II. STEP 2 — REMOVE SHIPPING RAILS

Remove shipping rails prior to lowering unit onto roof curb. See Fig. 2. The rails are attached to the unit at both the return end and condenser end. Remove the screws from both ends of each rail. Be careful not to drop the rails onto any surface that could be damaged. Discard the rails. It is impor- tant to replace the screws into the unit to avoid any air or water leakage.

CAUTION: Do not allow the shipping rail to drop on the roof surface. Damage to the roof surface may result.

III. STEP 3 — RIG AND PLACE UNIT

Inspect unit for transportation damage. See Tables 1-3 for physical data. File any claim with transportation agency.

CAUTION: All panels must be in place when rig- ging. Unit is not designed for handling by fork truck. Damage to unit may result.

Do not drop unit; keep upright. Use spreader bars over unit to prevent sling or cable damage. Rollers may be used to move unit across a roof. Level by using unit frame as a refer- ence; leveling tolerance is ± 1/16 in. per linear ft in any direc- tion. See Fig. 3 for additional information. Unit rigging weight is shown in Fig. 3.

Four lifting holes are provided in the unit base rails as shown in Fig. 3. Refer to rigging instructions on unit.

A. Positioning

Maintain clearance, per Fig. 4, around and above unit to pro- vide minimum distance from combustible materials, proper airflow, and service access.

Do not install unit in an indoor location. Do not locate air inlets near exhaust vents or other sources of contaminated air. For proper unit operation, adequate combustion and ven- tilation air must be provided in accordance with Section 5.3 (Air for Combustion and Ventilation) of the National Fuel Gas Code, ANSI Z223.1 (American National Standards Institute).

Although unit is weatherproof, guard against water from higher level runoff and overhangs.

Locate mechanical draft system flue assembly at least 4 ft from any opening through which combustion products could enter the building, and at least 4 ft from any adjacent build- ing (or per local codes). When unit is located adjacent to pub- lic walkways, flue assembly must be at least 7 ft above grade.

B. Roof Mount

Check building codes for weight distribution requirements. Unit operating weight is shown in Table 1.

C. Installation Onto Curb

The 581A units are designed to fit on the accessory full perimeter curb. Correct placement of the unit onto the curb is critical to operating performance. To aid in correct posi- tioning, 3/8-in. diameter locating holes have been added to the unit base rails. When placing the unit, these holes should line up with the roof curb edge as shown in Fig. 5 and 6, to assure proper duct opening alignment. For placement on the roof curb, use the alignment holes located approximately 2-in. from the end of the base rail on the return end of the unit. See labels on the side of the unit for more details.

CAUTION: Do not slide unit to position it when it is sitting on the curb. Curb gasketing material may be damaged and leaks may result.

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