Reznor YDSA Unit Installation Manual - Manual (Page 22)

Form I-Y, P/N 273646R6, Page 22
6.2 Duct
Connections
and Duct work
Requirements and Suggestions for Installing Ducts
Duct connections are in the roof curb designed for the unit; see FIGURE 2 on page 7,
FIGURE 3 on page 8 or FIGURE 4 on page 9 for duct connection sizes. Down flow roof
curbs are designed for installing duct work from the top before setting the unit on the
curb. Horizontal curbs have return air and supply air duct flanges on the side under the
condenser section. See Figure 5, page 11 or FIGURE 10, page 14 in Paragraph 5.3.
NOTE: All installations require a discharge air temperature sensor. See Paragraph
7.5.3 for placement of the discharge air sensor in the duct work.
• Type of Duct work - The type of duct installation to be
used depends in part on the construction of the roof
(whether wood joist, steel bar joist, steel truss, pre-
cast concrete) and the ceiling (whether hung, flush,
etc.).
• Duct work Material - Rectangular duct should be
constructed of not lighter than No. 26 U.S. gauge
galvanized steel or No. 24 B & S gauge aluminum.
• Duct work Structure - All duct sections 24 inches
(610mm) or wider, and over 48 inches (1219mm) in
length, should be cross broken on top and bottom and
should have standing seams or angle-iron braces.
Joints should be S and drive strip, or locked.
• Through Masonry Walls - No supply air duct should
come in contact with masonry walls. Insulate around
all air ducts through masonry walls with not less than
1/2” (13mm) of insulation. 1” (25mm) is recommended.
• Through Uncooled/Unheated Space - Insulate all
exposed supply air ducts passing through an uncooled
or unheated space with at least 1/2” (13mm) of
insulation. 1” (25mm) is recommended.
• Duct Supports - Suspend all ducts securely from
buildings members. Do not support ducts solely by the
unit duct connections.
• Duct Sizing - Proper sizing of the supply air duct work
is necessary to ensure a satisfactory installation. The
recognized authority for such information is the Air
Conditioning Contractors Association, 2800 Shirlington
Road, Suite 300, Arlington, VA 22206 (www.acca.
org). A manual covering duct sizing in detail may be
purchased directly from them.
• Duct Connections - To minimize sound and vibration
transmission, use flexible duct connections. Ducts
must be attached and sealed to provide airtight
connections.
• Return Air Duct/Grill Size - Make certain that return
air ducting or grill has a free area equal to the return
duct size connection.
CAUTION: An
external duct system
static pressure not
within the limits on
the rating plate may
overload the motor.
The cooling section drain pan is below the coil access door in the cooling section. The
1-1/4” drain connection is through the side of the cabinet.
Follow the instructions below to install a trap in the drain. Do not reduce the drain
diameter. Pitch the drain line at least 1/2” (13mm) for every 10 feet (3M) of horizontal
run. Drain lines must not interfere with access panels or doors.
An obstruction in the drain or a poorly designed drain can cause the condensate pan to
over flow. Overflow could result in damage to the unit and/or the building.
If the installation or local code requires, run drain into a waste water system.
6.3 Cooling Section
Condensate
Drain
NOTE: For condensate
drain for high-efficiency
gas heat section, see
Paragraph 9.2.
Control Access
Dual Gas Heat
Section
Hot
Air
Cool
Air
FIGURE 15 - When installing a
unit with a dual heat section,
avoid an immediate “T” in the
discharge (supply) duct.
An immediate “T” in the discharge duct
may allow stratification of the air resulting
in hot air only moving down one segment
of the duct.
Avoid this supply duct configuration. If the
configuration is not avoidable, provide air
mixing devices in the duct work.
Installing the Exhaust Hood on a Unit with
Option PE_ Power Exhaust
The exhaust opening is in the door panel.
1) Position the hood side to align with the
holes in the door panel. Attach with
sheetmetal screws.
2) Repeat to attach the other side.
3) Slide the top in place over the side panels.
Attach the top to the door and the side
panels.
FIGURE 14D -
Installing Exhaust
Hood for Power
Exhaust Option
PE__ without a
wheel
6.0 Mechanical (cont’d)