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Air Discharge Conversion
Unit sizes 007 thru 070 can be shipped as straight discharge
air or end discharge air arrangement . In the event that the
unit needs to be converted from straight discharge to end
discharge:
1 . Remove top panel .
2 . Remove the access panel to the fan motor . Remove the
piece of insulation at the bottom on the side of the bottom
panel .
3 . Remove the fan discharge panel, rotate it 180 degrees,
and move it to the other side . In other words, with straight
air discharge the housing is bottom horizontal and with
an end discharge the housing is top horizontal .
4 . Remove the three bolts holding the fan motor on and
rotate it so that the motor oilers are in the up position .
5 . Install insulation base panel below new access panel
location .
6 . Reinstall the top panel .
7 . Reinstall the piece of insulation and the access panel .
Ductwork & Attenuation
Discharge ductwork is normally used with these condition-
ers . Return air ductwork may also be required .
All ductwork should conform to industry standards
of good practice as described in the ASHRAE Systems
Guide .
The discharge duct system will normally consist of a
flexible connector at the unit, a transition piece to the full
duct size, a short run of duct, an elbow without vanes, and
a trunk duct teeing into a branch duct with discharge dif-
fusers as shown in Figure 2 . The transition piece must not
have angles totaling more than 30° or severe loss of air
performance can result . Do not connect the full duct size to
the unit without using a transition piece down to the size of
the discharge collar on the unit . With metal duct material,
the sides only of the elbow and entire branch duct should
be internally lined with acoustic fibrous insulation for sound
attenuation . Glass fiber duct board material is more absorb-
ing and may permit omission of the canvas connector .
The ductwork should be laid out so that there is no line of
sight between the conditioner discharge and the distribution
diffusers .
Return air ducts can be brought in through a low side
wall filter-grille and then up through the stud pieces to
a ceiling plenum or through air ceiling filter-grilles . The
ceiling filter-grille must not be placed directly under the
conditioner .
Return air ductwork can be connected to the standard
filter rack . See Figure 3 (side filter removal shown) . The filter
rack can be installed for bottom filter removal or side filter
removal by locating the brackets . For side filter removal the
brackets should be located on the bottom, left side, and top .
For bottom filter removal the brackets should be mounted on
the left side top and right side with the spring clips support-
ing the filter .
Do not use sheet metal screws directly into the unit cabi-
net for connection of supply or return air ductwork, espe-
cially return air ductwork which can hit the drain pan or the
air coil .
Figure 2. Suggested duct layout
Figure 3. Filter rack/return air duct collar
2x2 Ft .
Diffuser
(Example
Only)
Branch Duct
Internally Lined
With Acoustic
Fibrous
Insulation
Trunk Duct
Square Elbow
Canvas
Collar
Heat
Pump
Transformation
Piece
Discharge Collar
On Heat Pump
Both Sides Internally Lined With
Acoustic Fibrous Glass Insulation
Suggested Duct Layout For
Multiple Diffuser Application
Standard 1" (25mm)
Optional 2" (51 mm) Rack also
available.
Ventilation may require outside air . The temperature of the
ventilation air must be controlled so that mixture of outside
air and return air entering the conditioner does not exceed
conditioner application limits . It is also typical to close off
the ventilation air system during unoccupied periods (night
setback) .
Ventilation Air
The ventilation air system is generally a separate building
subsystem with distribution ductwork . Simple introduction of
the outside air into each return air plenum chamber reason-
ably close to the conditioner air inlet is recommended . Do
not duct outside air directly to the conditioner inlet . Provide
sufficient distance for thorough mixing of outside and return
air . See Operating Limits on page 8 .