Carrier 48/50HJ004-014 specifications Side View

DUCT OPENING SIZES
Supply = 15 11/16" x 31 3/8"
R1	= 15	5/16" x 29 1/16"
R2	= 15	5/16" x 9"	14"

R1 = Return from building to HVAC

R2 = Return from building to 62AQ

SIDE VIEW

			Deck pans
				2" Return support.
49	15/1	6"
				Only used on some
78 1/4"				applications.

3 1/4

R1

Deck pans

R 2

Supply

14"

2"

110 11/16"

49 15/16"

END VIEW

Fig. 2B — COBRA™ Energy Recovery Unit Full-Perimeter Roof Curb — 48/50HJ008-014 with 62AQ200,300

If electric control power or gas service is to be routed through the basepan, a field-installed accessory thru-the- bottom connection must be used. Attach the accessory to the basepan per the information in the accessory installation instructions. Thru-the-bottom connections must be installed before unit is set on roof.

If the combined unit roof curb is not being used, additional support may be desired under the energy recovery section of the unit. An accessory support and pad for the energy recovery section can be used. See Fig. 4. Place the protective rubber pad on the roof so that the edge near the unit is located about 6-in. from the end of the energy recovery section. Measure the distance from the bottom of energy recovery rails to the pad. Adjust the energy recovery equipment support to match the measured distance and screw into place with the 4 screws pro- vided. See Fig. 4. Place the support underneath the energy re- covery unit and on the protective rubber pad. This is done by lifting the end of the energy recovery section slightly above level and then sliding the support underneath the rails.

IMPORTANT: The gasketing of the unit to the roof curb is critical for a watertight seal. Install gasket supplied with the roof curb as shown in Fig. 3A and 3B. Improperly applied gasket can result in air leaks and poor unit performance.

Curb should be level. This is necessary for unit condensate drain to function properly. Refer to Accessory Roof Curb Installation Instructions for additional information as required.

Step 3 — Field Fabricate Ductwork — Secure all ducts to roof curb and building structure. Do not connect duct- work to unit. Insulate and weatherproof all external ductwork, joints, and roof openings with counter flashing and mastic in accordance with applicable codes. See Fig. 5A and 5B for duct dimensions.

Ducts passing through an unconditioned space must be insulated and covered with a vapor barrier. If a plenum return is used, the return should be ducted through the roof deck to com- ply with applicable fire codes.

A minimum clearance is not required around ductwork.

These units are designed for a minimum continuous heating return-air temperature of 50 F (dry bulb), or an intermittent operation down to 45 F (dry bulb), such as when used with a night set-back thermostat. To operate at lower return-air temperatures, a field-supplied outdoor-air temperature control must be used to initiate both stages of heat when the tempera- ture is below 45 F. Indoor comfort may be compromised when these lower air temperatures are used with insufficient heating temperature rise.

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