Model VCDRM-50
Round Multi-Blade Control Damper
Application
3.5 in.
(89mm)
The VCDRM-50 is an insert type multi-blade round
damper designed to provide optimum control of airflow
in round HVAC ductwork. The VCDRM-50 is intended
for applications in low to medium pressure and velocity
systems.
Ratings
Pressure:Up to 5 in. wg (1.2 kPa) - pressure
differential
Velocity: Up to 2500 fpm (12.7 m/s)
Temperature: Up to 180°F (82°C)
8.5
8
7
6
Standard
Optional
Galvanized Steel
304SS, Painted
14 ga. (2mm)*;
10ga. (3mm)**
-
Galvanized Steel
304SS, Painted
Opposed
Parallel
16 ga. (1.5mm)
-
3V
-
Axle Bearings
304SS
-
Axle Material
Plated Steel
304SS
Frame Material
Frame Thickness
Blade Material
Blade Action
Blade Thickness
Blade Type
4
3
D* (Dia.)
2
*D dimension furnished approximately 1/4 in. (6mm) undersize.
Leakage Data
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
Leakage testing was conducted in accordance with
0.2
AMCA Standard 500-D and is expressed as cfm/ft2 of
damper face area. All data has been corrected to represent
standard air at a density of 0.075 lb/ft3 (1.201 kg/m3).
VC
DR
M-
53
* under 22 in. (559mm) diameter
**over 22 in. (559mm) diameter
5
Static Pressure Difference (in. wg)
Construction
Minimum
Maximum
in. (mm)
11 in. (279)
48 in. (1219)
0.1
0.3 0.4 0.5 0.6 0.8 1
0.7 0.9
2
4
5
6 7
2
8.5
8
7
6
5
5
4
4
3
3
2
2
1.0
0.9
0.8
0.7
0.6
0.5
0.4
1.
0.
0.
0.
0.
0.
0.
0.3
0.
0.2
0.
RM
VC
D
1
2
3
4
5 6 7 8 9 10
20
Air Leakage in cfm/ft2
Installation instructions available at www.greenheck.com.
3
Air Leakage in cfm/ft
-50
Static Pressure Difference
Options
• Electric and pneumatic actuators
36 in.
(914mm)
8.5
8
7
6
* 1 in. (25mm) increments
0.2
Static Pressure Difference
Diameter*
30
40 50 60 70 80 90100
200
Pressure Drop
VCDRM-50
Pressure drop testing was conducted in accordance with AMCA Standard 500-D using the three configurations shown.
All data has been corrected to represent standard air at a density of
3
.075 lb/ft (1.2 kg/m3).
Actual pressure drop found in an HVAC system is a combination of many factors. This pressure drop information, along
with an analysis of other system influences should be used to estimate actual pressure losses for a damper installed in
an HVAC system.
Figure 5.3 Illustrates a fully ducted damper. This configuration has the lowest pressure drop of the three test
configurations because entrance and exit losses are minimized by straight duct runs upstream and downstream of the
damper.
Figure 5.2 Illustrates a ducted damper exhausting air into an open area. This configuration has a lower pressure drop
than Figure 5.5 because entrance losses are minimized by a straight duct run upstream of
the damper.
Figure 5.5 Illustrates a plenum mounted damper. This configuration has the highest pressure drop because of high
entrance and exit losses due to the sudden changes of area in the system.
5D
6D
Figure 5.3
5D
D =
Duct length
W =
Damper width
H=
Damper height
Figure 5.2
D=
Figure 5.5
4 (W) (H)
3.14
Dimension
inches
AMCA
figure
Velocity
(ft/min)
500
1000
1500
2000
2500
12
5.2
5.3
24
5.5
5.2
5.3
36
5.5
5.2
5.3
5.5
Pressure Drop in. wg
.04
.15
.33
.59
.93
.03
.11
.25
.45
.70
.05
.19
.42
.75
1.18
.03
.13
.29
.51
.79
.02
.10
.21
.38
.60
.04
.15
.33
.59
.92
.05
.19
.42
.75
1.18
.05
.20
.44
.79
1.23
.06
.25
.57
1.01
1.58
Copyright © 2017 Greenheck Corporation
VCDRM-50 Rev. 13 June 2017