Trane QFNA-IOM-1 - Manual (Page 17)

Q Fan Duct Connections
To maintain catalog performance
there must be a minimum of three
fan diameters of straight duct on the
fan inlet and minimum of one fan
diameter of straight duct on the fan
discharge. A 90° elbow at the
discharge should be a minimum of
two fan diameters from the fan
discharge. An open fan inlet should
never be closer than one fan
diameter from a bulkhead. Use an
inlet BELL for open inlet applications
to maintain rated performance.
Inlet ducts should be the same
diameter as the fan inlet. Outlet ducts
may be the same diameter as the fan
outlet or inlet. If the outlet duct is
equal to the inlet, either the duct
equalizer accessory or flexible
connection should be used to make
the transition. The inlet and outlet are
the same size on fan sizes 49-60".
See Tables 6 and 7 for inlet and
outlet diameters.
Flexible connections are
recommended for quiet operation an
and are required for units mounted
on vibration isolators. Flexible
connections should be fastened to
the inlet or outlet so that they do not
extend into either opening. Flexible
connections should not be stretched
tight. If the connections tend to sag
or are misaligned at the inlet, a
section of duct whose length is equal
to one-half the wheel diameter
should be attached to the fan inlet
ahead of the flexible connection.
In a horizontal run in which an
Arrangement 9 fan is bolted to a
floor, wall, or suspended from a
ceiling, ductwork may be flange or
slip connected as long as there is no
distortion of the fan shell due to the
duct weight. The same applies to
Arrangement 1 fans which are
always floor mounted.
Note: Flanged connections require
inlet or outlet flange accessory.
Access doors should be provided in
the inlet and outlet ducts if the
flexible connections do not permit
sufficient access to the fan. The
access doors should be large
enough to make possible visual
inspection of the bearing at the fan
inlet and removal of the end cone
access to the drive and rear bearing.
Super Q 11 Duct
Connections
Connect inlet and outlet ductwork to !
Super Q 11 duct collars. DO NOT
SUPPORT EXTERNAL DUCT
FROM THE DUCT COLLARS.
External ductwork should be
supported independently from the
floor to the ceiling.
To maintain catalog performance,
there must be a minimum of three
diameters of straight duct on the inlet
and minimum of one diameter of
straight duct on the discharge. A 90°
elbow at the discharge should be a
minimum of fan diameters from the
fan discharge. An open fan inlet
should never be closer than one fan
diameter from a bulkhead. Use an
inlet BELL for open inlet applications
to maintain rated performance for
sizes 49 through 60 only.
Installation —Q Fan
QFNA-IOM-1 17
Table 6 - Inlet and Outlet
Diameters for Q Fan
Unit
Size
Inlet Outlet
16
19
19-5/16
21-25/32
17-25/32
20-7/16
21
24
24-5/8
28-1/32
23-1/8
26-5/16
27
30
30-7/8
34-5/16
29
32-3/16
33
36
37-23/32
41-11/16 35-13/32
29-5/32
40
44 45-31/32
50-13/16 43-5/32
47-11/16
49
54 52-3/8
58-1/32
52-3/8
58-1/32
60 64-1/16 64-1/16
Table 7 - Inlet and Outlet
Diameters for Super Q II Fan
Unit
Size
Inlet Outlet
16
19
20-5/32
22-5/32 25-7/8
27-7/8
21
24
26-5/32
28-5/32 22-7/8
25-7/8
27
30
32-5/32
34-5/32 28-7/8
31-7/8
33
36
38-5/32
42-5/32 38-5/32
42-5/32
40
44
46-5/32
48-5/32 46-5/32
48-5/32