7
Energy Recovery Ventilator
R
ot
atio
n
Length of Straight Duct
GOOD
4.844
1.549
0.775
Insulation Pan
(Insulation not included)
Unit Base
Roof Curb
1.895
Unit Side
Curb Cap Details for Factory Supplied Roof Curbs
Curb Outside Dimensions -
continued
Recommended Discharge Duct Size and Length
Model
Blower Size Duct Size Straight Duct Length
ERV
e
-20
9
14 x 14
36
ERV
e
-35
10
20 x 20
36
ERV
e
-45
12
20 x 20
36
ERV
e
-55
15
28 x 28
60
All dimensions shown in inches.
• Recommended duct sizes are based on velocities across the
cfm range of each model at approximately 800 feet per minute
(FPM) at minimum airflow and up to 1600 fpm at maximum
airflow. Recommended duct sizes are only intended to be a
guide and may not satisfy the requirements of the project.
Refer to plans for appropriate job specific duct size and/or
velocity limitations.
• Straight duct lengths were calculated based on 100% effective
duct length requirements as prescribed in AMCA Publication
201. Calculated values have been rounded up to nearest foot.
Ductwork Connections
Examples of poor and good fan-to-duct connections
are shown below. Airflow out of the fan
should be directed straight or curve
the same direction as
the fan wheel rotates.
Poor duct installation
will result in low airflow
and other system
effects.
R
ot
atio
n
POOR
Isometric view of
ERV
e
on rails
Side view of
ERV
e
on rails
A
B
Unit Size
A
B
ERV
e
-20
5.75
18
ERV
e
-35
5.75
20.5
ERV
e
-45
6
22.5
ERV
e
-55
6
26
All dimensions are in inches.
Rail Mounting / Layout
1. Rails designed to handle the weight of the ERV
e
should be positioned as shown on the diagram
(rails by others).
2. Make sure that rail positioning does not interfere
with the supply air discharge opening or the
exhaust air intake opening on the ERV
e
unit.
Avoid area dimensioned “B” below.
3. Rails should extend beyond the unit a minimum
of 12 inches on each side.
4. Set unit on rails.
