Orion System OE742-XX-VAVZ - Manual (Page 21)

Form: Orion-OE524-XX-PD-RndPDDmpr-Sub-01A
Page 2 of 2
Using the maximum acceptable velocity for a branch duct (typi-
cally 1000-1500 FPM for minimal noise), find the smallest
Round Zone Damper that will deliver the required CFM as de-
termined by the load program. Locate the branch velocity used
in the duct design program in the left hand column of the Round
Zone Damper Selection Data table. Move across the table and
find the Round Zone Damper, which will provide the acceptable
CFM to meet the zone airflow requirements.
Note:
Compare the Round Zone Damper size selected
against the duct size to determine if the next size
up or down will provide acceptable performance
without requiring a transition fitting.
Up to a maximum of two Slaved Round Zone Dampers may be
slaved together with the main Round Zone Damper for large
zones. This design should be reserved only for situations when
it is not practical to use a single Round Zone Damper. See the
Round Slaved Zone Damper specification sheet for information
regarding application and selection of Round Slaved Zone
Dampers.
OE524-XX-PD Round Pressure
Dependent Zone Damper
Round Pressure Dependent
Zone Damper Sizing
Use a load program to determine the peak load
for each zone. These calculations will be used
to select Round Pressure Dependent Zone
Damper sizes.
The Orion Systems utilize a typical low pres-
sure duct design. To reduce noise problems,
pressures should not exceed 1” W.C. in the
duct.
Primary trunk ducts used with Orion systems
should not be “undersized”. This is especially
true of “pressure dependent” systems. With
larger trunk ducts, it is easier to assure relative-
ly constant pressure to each Round Zone
Damper. Runs should be as short as possible,
and the trunk duct system kept as symmetrical
as possible to facilitate system balancing.
Wherever possible, run the trunk ducts above
corridors and locate the Round Zone Dampers
above corridors to reduce the noise in the
space and facilitate service of the valves. Trunk
ducts should be sized for no more than 0.1”
W.C. drop per 100 ft. of duct, and a maximum
duct velocity of 2000 FPM.
Round Zone Damper Selection Data OE524-XX-PD Pressure Dependent
Round Zone Damper
VAV/Zone Damper Round Duct Size
(Area Ft
2
)
6”
(0.196)
8”
(0.349)
10”
(0.545)
12”
(0.785)
14”
(1.069)
16”
(1.396)
Velocity Through VAV/Zone Damper
FPM
Airflow Through VAV/Zone Damper - CFM
(
P
S
inches W.C. w/ Air Damper Full Open)
500
98
(< 0.01)
175
(< 0.01)
273
(< 0.01)
393
(< 0.01)
535
(< 0.01)
698
(< 0.01)
750
147
(0.01)
262
(0.01)
409
(0.01)
589
(< 0.01)
802
(< 0.01)
1047
(< 0.01)
1000
196
(0.015)
349
(0.015)
545
(0.01)
785
(< 0.01)
1069
(< 0.01)
1396
(< 0.01)
1250
245
(0.025)
436
(0.02)
681
(0.015)
981
(0.015)
1336
(0.015)
1745
(0.015)
1500
294
(0.035)
523
(0.035)
818
(0.022)
1178
(0.020)
1604
0.020)
2094
(0.020)
1750
343
(0.045)
611
(0.035)
954
(0.034)
1374
(0.030)
1871
(0.030)
2443
(0.025)
2000
392
(0.065)
698
(0.043)
1090
(0.040)
1570
(0.040)
2138
(0.040)
2792
(0.030)
WattMaster reserves the right to change specifications without notice