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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 control; 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 the
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
20”
3300
22”
4000
24”
4700
PART #
SIZE
D
L
W
STBP08
8
8” 10” 11”
STBP10
10
10” 12” 13”
STBP12
12
12” 14” 15”
STBP14
14
14” 16” 17”
STBP16
16
16” 18” 19”
STBP18
18
18” 23” 21”
STRDBP20
20
20” 24” 27”
STRDBP22
22
22” 24” 27”
STRDBP24
24
24” 24” 27”
ROUND BYPASS SELECTION TABLE
4”
H
D
W
48” MAXIMUM WIDTH
RECTANGULAR BYPASS DAMPERS
SELECT FROM 8 x 8 thru 48 x 48
D
L
W
BYPASS DAMPERS- ELECTRONIC
