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CONTROLS
NOTICE: Dual Duct Air Terminals with digital
controls, if factory programmed, incorporate specific
communication addresses. Installing the Dual Duct Air
Terminal in a different location than noted on the Dual
Duct Air Terminal label and building plans may result in
excessive start-up labor and is the sole responsibility of
the contractor.
For information on controls provided by other
manufacturers and installed on the Air Terminals,
contact the local branch or dealer.
INLET FLOW SENSOR
Dual Duct Air Terminals are shipped with factory-
installed (where applicable) pressure differential inlet
flow sensors in the primary inlet. See figure 4 for
calibration curve and K factors. Bypass Air Terminals
offer an optional downstream flow sensor for field
installation a minimum of 3 feet downstream of
box discharge.
Troubleshooting
Investigating Noise Complaints
• Noise from a Dual Duct Air Terminal can be due to a
variety of conditions and can be difficult to eliminate.
• The first step is to isolate the type, source and
direction.
• Generally, noise heard at the air outlet is considered a
discharge type.
• Noise heard through the ceiling is considered radiated
noise.
• For detailed information concerning noise
transmission in buildings, refer to AHRI Standard
885-2008, "Procedure for estimating occupied space
sound levels in the application of air terminals and
air outlets."
Discharge Noise
• This is usually caused by high static pressure or
little to no internal duct lining downstream of the Air
Terminal.
• It can sometimes be caused by the air outlet itself.
• Air outlet generated sounds can be reduced by
reducing flow or increasing an outlet size.
• Reducing static pressure, flow or adding additional
downstream attenuation materials will reduce
discharge sounds from the Air Terminal.
Radiated Noise
• Radiated noise is most commonly associated with Fan
Powered Terminals.
Dual Duct VAV Terminals
7
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