Reznor RBL (Cabinet Blower) Unit Installation Manual User Manual

Page 3

Form I-RBL, P/N163219R2, Page 3

4x4 Treated Lumber

FIGURE 3 - Support Rail Dimensions

Configuration

Standard Model RBL 59-1/16" (1500mm) 53-9/16" (1361mm)
Model RBL with

Downturn Cabinet

82-1/16" (2084mm) 53-9/16" (1361mm)

Mounting on a Roof Curb - Whether using an optional roof curb available for the cabinet or a field-supplied curb, the

curb must be square and level and a minimum height of 14" (356mm). The top surface of the roof curb must be caulked

with 1/4" x 1-1/4" sealant tape or 1/4" beads of suitable sealant. The cabinet must be sealed to the curb to prevent water

leakage into the curb area due to windblown rain and capillary action. Except for the curb assembly details, the informa-

tion and requirements in this section apply to both an optional curb and a field-supplied curb. See

FIGURE 5 and curb

installation instructions.
Bottom Duct Connections - Both the optional return air opening and the opening in the downturn plenum have duct

flanges. Duct opening sizes and spacing in relation to an optional roof curb are shown in

FIGURE 4.

The blower cabinet may be mounted on an optional roof curb, a field-supplied roof

curb, or field supplied supports. If the system has a downturn plenum and/or a bottom

return air opening, a roof curb is recommended to provide a weatherproof installation

as well as more workable clearances for ductwork. The blower cabinet curb cap is not

designed to be placed directly on the roof surface. When positioning rooftop equip-

ment, it is recommended that the air inlet does not face into the prevailing wind.
Mounting on Field Supplied Supports (without a roof curb) - Prior to installation,

be sure that the method of support is in agreement with all local building codes and is

suited to the climate. If considering this type of installation in snow areas, it is recom-

mended that the 4x4 wooden rails underneath the unit be on cross-support structure

at least 12" (305mm) higher than the roof surface. Whether the supports are being

mounted directly on the roof or being placed "up" on additional structure, the horizontal

length of the unit should be supported by two 4x4 treated wooden rails. Cut the rails

to the appropriate length (Dimension "A") in

FIGURE 3. (NOTE: Although dimensions

are included for units with a downturn plenum cabinet, it is strongly recommended that

a roof curb be used on an installation with a downturn plenum cabinet and/or a bottom

return air duct.) Space the 4x4 wooden support rails (See "B" Dimension in

FIGURE 3)

so that the curb cap "skirt" will fit over the edge of the boards with the rail setting inside

the horizontal length of the curb cap.
If the rails are being laid directly on the roof, position them as shown in

FIGURE 3. Set

the unit on the rails.

NOTE: It is recommended that there be a minimum of 14" between

the bottom of the inlet air hood (see Paragraph 5.1.2) and the mounting surface.
If the treated wooden rails are not placed directly on the roof surface, cross supports

should be placed underneath the rails at the ends of the cabinet. The field-supplied,

weather-resistant cross-support structure must be adequate for the weight of the unit

and run the entire width of the cabinet supporting the 4x4 wooden rails.

1-5/8

(41)

1-5/8

(41)

1-5/8 (41)

19-1/2

(495)

19-1/2

(495)

Bottom

Return

Duct

Supply

Duct

(applies to

RBL with

downturn

only)

Roof Curb

1-5/8

(41)

1-5/8

(41)

Dimensions

Standard RBL

Cabinet

47-5/8"

(1210mm)

RBL w/Down-

turn Plenum

55-13/16"

(1418mm)

47-5/8"

(1210mm)

FIGURE 4 - Roof Curb and Optional Duct

Opening Dimensions - inches (mm)

Return and Supply Duct Dimensions and

Locations are in relation to Reznor Optional

Roof Curbs.)

1-5/8" (41mm) is measurement from duct

opening to

inside edge of roof curb.

NOTE: Cut duct openings 1" (25mm) larger

than the duct size for installation clearance.