Extruded BACKDRAFT DAMPER
ADJUSTABLE COUNTERBALANCE
EM-40 SERIES
Horizontal Mount - Vertical Airflow Down
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)
H*
differential pressure
Velocity: 2500 to 3500 fpm (13m/s - 18 m/s)
Temperature: 180°F (82ºC)
Standard Construction
Frame: Heavy gauge 6063T5 extruded aluminum.
W*
(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
*W & H dimensions furnished approximately 1/4 in. (6mm) under size.
Bearings: Synthetic (acetal) sleeve type
Linkage: 1/8 in. (3mm) plated steel
3 in.
5 in.
Blade Seals: Vinyl
EM-40
3 1/8 in.
No Flange
11 1/8 in.
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)
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.
EM-41
Flange On
Discharge
1 1/2 in.
Options and Accessories
• 11/2 in. flange on discharge: EM-41
1 1/2 in.
• 11/2 in. flange on intake:
EM-42
EM-42
Flange On
Intake
• 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:
Maximum Set
Pressure
in. wg (Pa)
2
Area ft
(m )
2
4 (.37)
6 (.56)
.75 (187)
.50 (125)
.40 (100)
.30 (75)
.20 (50)
.15 (37)
.125 (31)
8 (100)
10 (.93)
15 (1.39)
20 (1.86)
24 (2.23)
Counterbalance weights may require field adjustment. Instructions are
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