Installation and Maintenance Manual

VAV-SVX08E-EN 13
Unit Installation
Due to their weight, the VAV terminal units should be
suspended from the uppermost ceiling, independent of
the false ceiling grid. Suspension devices are to be
supplied by the installer. Units must be installed level and
upright. Failure to level the unit properly may prevent
proper operation of the controls and/or terminal unit.
Units are not designed to be installed vertically.
Consequently, this will also void the UL ratings and any
warranty on the unit.
Single-Duct
Depending upon the size and weight of the single-duct
unit, it may be capable of being supported by the ductwork
that is connected to it. No hanger brackets are provided on
these units since the unit should be supported by means
of a hanger strap. The hanger strap should be secured
directly to the unit casing as shown in Figure 9, p. 13.
For cooling only single-duct units or single-duct units with
hot water coil, the unit may be rotated 180° for opposite
side connections.
For units with electric heat, the unit can be flipped to either
RH or LH connection orientation if model number digit 22
Electrical Connections = F.
Dual-Duct
Dual-duct units should be supported by either hanger
straps or by using a threaded rod in conjunction with the
hanger brackets that are provided on the unit. See
Figure 10, p. 13.
Fan-Powered (Standard and Low-Height)
Fan-powered units should be supported by either hanger
straps or by using a threaded rod in conjunction with the
hanger brackets that are provided on the unit. Care should
be exercised to insure that the hanging straps do not block
the side access panel. See Figure 11, p. 16 thru Figure 18,
p. 22.
Duct Connections
All VariTrane units should be provided with a minimum of
1.5-duct diameters of straight duct prior to the inlet of the
unit. It is recommended that at least 48 inches of straight
duct be provided from the discharge of the units prior to
any take-offs or transitions.
Important: This is a requirement for electric heat fan-
powered units used in applications with
100% downward discharge.
Note: In order to maintain good air distribution over the
elements and not create turbulence which could
cause a limit cutout there should be four feet of
ductwork, consistent of the discharge dimensions
of the heater. downstream of the reheat coil prior to
any diffuser takeoffs for VariTrane™ electric coils.
1. After all connections are made, check that the entire
ductwork system is airtight. In some high-pressure
systems, duct sealer may be necessary.
Note: All inlet duct on the VAV boxes are sized
approximately 1/8" smaller in diameter than the
nominal size in order to allow the incoming duct
to slide over the inlet of the VAV box.
2. Provide insulation around the entire inlet collar (all the
way to the unit casing).
WARNING
Proper Structural Support Required!
Ceiling structure must be strong enough to support the
weight of the unit. If unsure, check with a structural
engineer. Refer toTable 1, p. 24 thruTable 6, p. 26 for unit
weights. Failure to ensure proper structural ceiling
support could result in unit failing from its location
which could result in death or serious injury.
Figure 9. Single-duct hanging recommendations
.
Figure 10. Dual-duct hanger bracket locations
Inlet Size
B C A
1.376" (35 mm)
25.154" (639 mm) 1.376" (35 mm)
37.25" (946 mm)
25.25" (641 mm) 23.154" (588 mm)
12" thru 16"
5" thru 10"
AIR
VALVE
AIR
VALVE
COOLING
HEATING
C
A
B
TOP VIEW