Installation, Effect of installation on performance, Inlet duct turns discharge duct turns – Greenheck TCB/TCBRU/TCBRS (456557) User Manual
Page 2: Typical installations, Mounting hole location
INSTALLATION
EFFECT OF INSTALLATION ON PERFORMANCE
Any installation with inlet or discharge configurations that deviate from these recommendations may result in reduced fan
performance. Restricted or unstable flow at the fan inlet can cause pre-rotation of incoming air or uneven loading of the fan
wheel yielding large system losses and increased sound levels. Free discharge or turbulent flow in the discharge ductwork will
also result in system effect losses.
The most common inlet and discharge conditions which affect fan performance are:
INLET DUCT TURNS
DISCHARGE DUCT TURNS
Horizontal Base Mount
Motor at 3 or 9
o’clock position
Vertical Base Mount
w/ airflow up or down
Fan
Roof Opening
Size
A
B
Depth*
TCBRU
TCBRS
9
17
1
/
2
26
18
3
/
8
14 x 14
16 x 16
10
17
1
/
2
26
18
3
/
8
14 x 14
16 x 16
12
17
1
/
2
26
18
3
/
8
14 x 14
16 x 16
13
19
28
1
/
2
19
7
/
8
16 x 16
18 x 18
16
21
3
/
4
33
23
7
/
8
18 x 18
22 x 22
18
26
1
/
4
37
26
3
/
8
20 x 20
28 x 28
22
30
1
/
2
44
29
5
/
8
24 x 24
34 x 34
24
35
50
33
1
/
8
26 x 26
40 x 40
30
42
56
42
5
/
8
32 x 32
46 x 46
36
46
3
/
4
62
48
1
/
8
38 x 38
52 x 52
TCBRU Installation
Curb Mounted
TCBRS Installation
Curb Mounted
TYPICAL INSTALLATIONS
Following are typical mounting installations for models TCB (horizontal or vertical mounting), TCBRU, and TCBRS. For TCB's
with motor in the 3 or 9 o'clock position or vertical installations, additional mounting rails are recommended. Mounting rail
dimensions are shown for field fabrication.
Good
Poor
Length of Straight Duct
0
0.2
0
1 Fan
Wheel
Dia.
Turning
Vanes
ROOF
CURB
CURB
CAP
Horizontal Ceiling Hung
Vertical Ceiling Hung
Mounting Hole Location
A
Optional Mounting
Rails
B
B
Optional Mounting
Rails
Installation of a duct turn or elbow too close to the fan inlet
reduces fan performance because air is loaded unevenly
into the fan wheel. To achieve full fan performance there
should be at least one to two fan wheel diameters between
the turn or elbow and the fan inlet.
Fan performance is reduced when duct turns are
made immediately off the fan discharge. To achieve
cataloged fan performance, there should be at least
one equivalent duct diameter of straight ductwork
between the fan discharge and any duct turns.
*Depth dimension is the center distance between
holes in the front and rear mounting brackets
Poor
Good