32
SCXF-SVX01T-EN
Figure 18. Optional spring isolator dimensional data
Duct Connections
Return air enters the rear of the unit and conditioned supply
air discharges through the top. Attach supply air ductwork
directly to the unit’s top panel, around the fan discharge
opening. A duct collar is not provided.
Note: Units equipped with flexible horizontal discharge
plenum option may include a duct collar when holes
are factory cut. If discharge openings are field-cut,
refer to the following “Installation — Plenum” section.
Install all air ducts according to the National Fire Protection
Association standards for the “Installation of Air
Conditioning and Ventilation Systems other than
Residence Type (NFPA 90A) and Residence Type Warm
Air Heating and Air Conditioning Systems (NFPA 90B).
Make duct connections to the unit with a flexible material
such as heavy canvas. If a fire hazard exists, Trane
recommends using Flexweave 1000, type FW30 or
equivalent canvas. Use three inches for return duct and
three inches for discharge duct. Keep material loose to
absorb fan vibration.
• If using return ductwork to the unit, secure it with three
inches of flexible duct connector.
• Extend discharge duct upward without change in size
or direction for at least three fan diameters.
• Use 3" flexible duct connection on discharge ductwork.
Note: Compressors and fan assembly are internally
isolated. External isolation devices (spring mounting
isolators) are at discretion of a vibration specialist
consulted by building or HVAC system designer.
Run the ductwork straight from the opening for a minimum
of three fan diameters. See Figure 19, p. 32. Extend
remaining ductwork as far as possible without changing
size or direction. Do not make abrupt turns or transitions
near the unit due to increased noise and excessive static
losses. Use elbows with splitters or turning vanes to
minimize static losses.
Poorly constructed turning vanes may cause airflow
generated noise. Align the fan outlet properly with the
ductwork to decrease noise levels in the duct and to
increase fan performance. To complete trunk ductwork to
the VAV terminal units, refer to the VAV box manuals for
specific requirements. Check total external static pressures
against fan characteristics to be sure the required airflow is
available throughout the ductwork.
To achieve maximum acoustical performance, minimize the
duct static pressure setpoint.
Figure 19. Duct connection recommendations
3 Fan
Diameters
Duct
Discharge
3-inch
Duct
Flexible
Air
Return
Installing the Plenum
Before installing plenum, attach insulation strip that ships
with plenum. See Figure 20, p. 33 for proper insulation
location. Align plenum front with control panel side of unit.
Using strips and screws provided, secure plenum to unit.
Treat field-cut holes to prevent fiberglass from entering the
air stream.
Installation - Mechanical
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