Application and Design
The EM-40 series is a horizontally mounted backdraft damper that is designed to allow vertical airflow down and prevent
reverse airflow. The damper is opened by air pressure differential and closed by gravity. Standard models include adjustable
counterbalance weights to assist closing.
Ratings
(See page 2 for specific limitations)
Pressure:
4.0 - 10.0 in. wg (996 Pa - 2491 Pa)
differential pressure
Velocity:
2500 to 3500 fpm (13m/s - 18 m/s)
Temperature:
180°F (82ºC)
Standard Construction
Frame:
Heavy gauge 6063T5 extruded aluminum.
(0.125 in.[3.2mm] thickness)
Blades:
Heavy gauge 6063T5 extruded aluminum.
(0.070 in. [1.8mm] thickness)
Axles:
3
/
4
in. (19mm) dia. metallic
Bearings:
Synthetic (acetal) sleeve type
Linkage:
1
/
8
in. (3mm) plated steel
Blade Seals:
Vinyl
Size Limitations
Minimum Size:
8 in. W x 11 in. H
(203mm x 279mm)
Maximum Panel Size:
48 in. W x 74 in. H
(1219mm x 1880mm)
Options and Accessories
• 1
1
/
2
in. flange on discharge: EM-41
• 1
1
/
2
in. flange on intake:
EM-42
• APC (Adjustable Pressure Controller).
Allows field setting of relief pressure on
all EM dampers. Use one per panel.
Maximum recommended pressure set
limitations are as follows:
EM-40 SERIES
Horizontal Mount - Vertical Airflow Down
Sizes larger than maximum shown will be supplied
as two or more equal size smaller dampers required
to make up the size specified. These larger multiple
damper assemblies require field assembly and may
require additional reinforcement (not supplied by
Greenheck) to support the assembly.
*W & H dimensions furnished approximately
1
/
4
in. (6mm) under size.
Extruded
BACKDRAFT DAMPER
ADJUSTABLE COUNTERBALANCE
3
1
/
8
in.
Airflow
1
1
/
2
in.
1
1
2
in.
3 in.
5 in.
11
1
/
8
in.
/
EM-40
No Flange
EM-41
Flange On
Discharge
EM-42
Flange On
Intake
Area ft2
(m2)
Maximum Set
Pressure
in. wg (Pa)
4 (.37)
.75 (187)
6 (.56)
.50 (125)
8 (100)
.40 (100)
10 (.93)
.30 (75)
15 (1.39)
.20 (50)
20 (1.86)
.15 (37)
24 (2.23)
.125 (31)
Counterbalance weights may require field adjustment. Instructions are
available at www. greenheck.com.
W*
H*
