INSTALLATION
Unit is shipped in the vertical air¯ow con®guration. See Fig. 1. To convert to horizontal discharge, remove horizontal duct opening covers. Using the same screws, install covers with
Model 581B meets the California maximum oxides of nitro- gen (NOx) emission regulations when equipped with acces- sory NOx Reduction Kit (part no.
These units are equipped with an
These units are designed for a minimum continuous return air temperature of 50 F (dry bulb) or an intermittent opera- tion down to 45 F (dry bulb), such as when used with a night
All units can be connected into existing duct systems that are properly sized and designed to handle an air¯ow of 300 to 500 cfm per each 12,000 Btuh of rated cooling capacity.
NOTE: When installing any accessory or
I. LOCATE THE UNIT
A. Clearance
Maintain clearance around and above unit to provide mini- mum distance from combustible materials, proper air¯ow, and service access. See Fig. 2 and 3.
Minimum clearance to combustibles is 48 in. on ¯ue side; bot- tom of unit (when not using curb) is 1 inch; bottom of base rail (when not using curb) is 0 inches.
Minimum clearance on all sides to block walls or any other grounded surface is 42 inches. Between unit and ungrounded surfaces, control box side is 36 inches; between units, control box side, is 42 inches.
Fig. 3 Ð Service and Operational Clearances
Minimum clearance of condenser coil is 36 in. on one side, 12 in. the other. Side getting greater clearance is optional.
Minimum distance overhead is 60 inches.
Locate the unit where the vent cap will be a minimum of 4 ft from openable windows and doors.
Do not install unit in an indoor location. Do not locate unit air inlets near exhaust vents or other sources of contami- nated air.
Be sure that unit is installed so that snow will not block the combustion intake or ¯ue outlet.
Although unit is weatherproof, guard against water from higher level runoff and overhangs.
Locate mechanical draft system ¯ue assembly at least 48 in. from any opening through which combustion products could enter the building, and at least 24 in. from an adjacent build- ing. When unit is located adjacent to public walkways, ¯ue assembly must be at least 7 ft above grade.
Flue gas can deteriorate building materials. Orient unit such that ¯ue gas will not affect building materials.
Adequate
Flue vent discharge must have a minimum horizontal clear- ance of 4 ft from electric and gas meters, gas regulators, and gas relief equipment.
B. Roof Curb Mount
Assemble and install accessory roof curb in accordance with instructions shipped with curb. See Fig. 4. Install insulation cant strips, roo®ng felt, and counter ¯ashing as shown. Duct- work must be attached to curb. If gas, electric power, or con- trol power is to be routed through the curb, attach the utility connection plates to the roof curb in accordance with the ac- cessory installation instructions. Accessory electric and gas utility connection plates must be installed before unit is in place on roof curb.
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. 4. Improperly applied gasket can also result in air leaks and poor unit performance.
Curb should be level. This is necessary for unit drain to func- tion properly. Unit leveling tolerances are shown in Fig. 5.
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 condenser- coil air inlet to prevent grass and foliage from obstructing air¯ow.
NOTE: Horizontal units may be installed on a roof curb if required.
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