DUCTWORK
Ductwork should be designed and sized according to the
methods in Manual Q of the Air Conditioning Contractors of
America (ACCA).
A closed return duct system shall be used. This shall not
preclude use of economizers or outdoor fresh air intake. The
supply and return air duct connections at the unit should be
made with flexible joints to minimize noise.
The supply and return air duct systems should be designed for
the CFM and static requirements of the job. They should NOT
be sized to match the dimensions of the duct connections on
the unit.
CAUTION: When fastening ductwork to side duct flanges on
unit, insert screws through duct flanges only. DO
NOT insert screws through casing.
O ut do or du ct wor k m us t be ins ul ate d a nd
waterproofed.
Refer to Figure 10 for information concerning side and bottom
supply and return air duct openings.
FIXED OUTDOOR AIR INTAKE DAMPER
This damper is shipped inside the return air compartment on units
that are not provided with an economizer or a motorized damper
option. It is completely assembled and ready for installation. A
damper baffle inside of the hood is adjustable to provide variable
amounts of outdoor air intake. Refer to Figure 3.
Gasketing and mounting screws are provided in a parts bag
attached to the hood assembly. Apply gasketing to the three
flange surfaces on the hood prior to installing the hood. Extend
gasketing 1/4" beyond the top and bottom of the two side
flanges to insure adequate sealing.
Adjusting the damper to the desired air flow may be done
before mounting the hood into position or (after installation) by
removing the front hood panel or the screen on the bottom of
the hood. Damper baffle in position 1 will allow approximately
10% recirculated air flow, position 2 approximately 15% and,
to allow approximately 25%, remove the damper baffle.
On units with bottom return air applications, install the damper
assembly over the opening in the side return air access panel.
Remove and discard the opening cover and the covering over
the hood mounting holes (used for shipping) before installing.
Secure with the screws provided.
On units with side return air applications, install the damper
assembly on the return air ductwork as close to the unit as
possible. Cut an opening 16" high by 18" wide in the ductwork
to accommodate the damper. Using the holes in the hood
flanges as a template, drill 9/64" dia. (#26 drill) holes into the
ductwork and secure with the screws provided.
CAUTION: If outdoor air intake will not be required on units
with bottom return air applications, the damper
assembly should still be mounted on the side return
air access panel, per the instructions above, to
insure moisture is not drawn into the unit during
operation. The covering over the mounting holes
only need be removed. Do not remove the opening
cover.
CONDENSATE DRAIN
Plumbing must conform to local codes. Use a sealing
compound on male pipe threads. Install a condensate drain line
from the 1" NPT female connection on the unit to an open drain.
An alternate drain connection (1" NPT female coupling) is
provided inboard on the same centerline as the exterior
location.
NOTE: The condensate drain line MUST be trapped to provide
proper drainage. See Figure 4.
COMPRESSORS
Units are shipped with compressor mountings factory-adjusted
and ready for operation.
CAUTION: Do Not loosen compressor mounting bolts.
FILTERS
2" filters are supplied with each unit. Filters must always be
installed ahead of the evaporator coil and must be kept clean
or replaced with same size and type. Dirty filters will reduce the
capacity of the unit and will result in frosted coils or safety
shutdown. Minimum filter area and required sizes are shown
in Table 4.
SERVICE ACCESS
Access to all serviceable components is provided by the
following removable panels:
•
Compressor compartment
•
Electric Heat compartment - DCE models
•
Gas Heat compartment (Two panels) - DCG models
•
Side Supply & Return Air compartments (Two panels)
•
Blower compartment (Three panels)
•
Main control box
•
Filter compartment
•
Outdoor Air compartment (Two panels)
Refer to Figure 10 for location of these access panels.
CAUTION: Make sure that all screws and panel latches are
replaced and properly positioned on the unit to
maintain an air-tight seal.
FIG. 3 - FIXED OUTDOOR AIR DAMPER
58-1/4
FIG. 4 - RECOMMENDED DRAIN PIPING
It is recommended that, in Canada, the outlet duct on gas
heating units be provided with a removable access panel. It
is recommended that this opening be accessible when the unit
is installed in service, and of a size such that smoke or
reflected light may be observed inside the casing to indicate
the presence of leaks in the heat exchanger. The cover should
be attached in a manner adequate to prevent leakage.
530.18-N11Y
4
Unitary Products Group
