Zonex DigiTract 4 - BYPASS DAMPERS - ELECTRONIC; SIZING ELECTRONIC BYPASS DAMPERS; ROUND BYPASS DAMPER SELECTION; RECTANGULAR BYPASS DAMPER SELECTION

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ELECTRONIC BYPASS DAMPERS
Bypass dampers are used to provide constant air delivery through the air handling unit. This is done by bypassing excess air
from the supply duct back to the return duct. As a zone is satisfied, its zone damper closes. When this happens, the bypass
damper opens just enough to bypass the excess air. This will control static pressure and noise at the diffusers.
The Electronic Bypass Damper is used on any size system over 5 tons. The damper can be round (STBP) or rectangular
(STCDBP) with integrated static pressure con
trol; and multiple dampers can be slaved together.
SIZING ELECTRONIC BYPASS DAMPERS
The bypass damper is to be sized for the total system CFM
@ 1500 FPM. System CFM should be calculated at 400
CFM per ton.
Example : A 5-ton system is rated at 2000 CFM (5x400 =
2000). When calculated at 1500 FPM, the bypass damper
should be 16”. Never undersize the bypass damper.
ROUND BYPASS DAMPER SELECTION
The Zonex Systems STBP damper is used for round
bypass applications. When you know th
e bypass CFM
requirements, use the ROUND BYPASS SELECTION
TABLE to confirm the round damper size.
NOTE: Multiple round dampers can be slaved from one
static pressure control to provide the correct capacity. One
large rectangular bypass damper may be used instead of
multiple round dampers. See below.
RECTANGULAR BYPASS DAMPER SELECTION
The Zonex Systems STCDBP WxH damper is used for
rectangular bypass applications. These dampers are also
sized for
the total system CFM rated at 1500 FPM.
Multiple dampers can be slaved from a single static
pressure control.
Diameter CFM
8”
560
10”
900
12”
1250
14”
1700
16”
2200
18”
2600
PART # SIZE D L W
STBP 08
8
8”
10”
11”
STBP 10
10
10”
12”
13”
STBP12
12
12”
14”
15”
STBP 14
14
14”
16”
17”
STBP 16
16
16”
18”
19”
STBP 18
18
18”
20”
21”
ROUND BYPASS SELECTION TABLE
RECTANGULAR BYPASS DAMPERS
SELECT FROM 8 x 8 thru 48 x 48
D
L
W
H
D
4”
W
48” MAXIMUM WIDTH
BYPASS DAMPERS - ELECTRONIC