Table of Contents
Advertisement
Roof Curb Mounting
Roof curb details including duct location dimensions,
are available on ERV Roof Curb Assembly Instructions.
Rooftop units require curbs to be mounted first. The
duct connections must be located so they will be clear
of structural members of the building.
1. Factory Supplied Roof Curbs: Roof curbs are
Model GKD. The GKD ships in a knockdown kit
(includes duct adapter) and requires field assembly
(by others). Assembly instructions are included with
the GKD curbs.
2. Install Curb: Locate curb over roof opening and
fasten in place. (Refer to Recommended Roof
Openings & Weights). Check that the diagonal
dimensions are within ±1/8 inch of each other and
adjust as necessary. For proper unit operation, it
is important that the installation be level. Shim as
required to level.
3. Install Ductwork: Installation of all ducts should
be done in accordance with SMACNA and AMCA
guidelines. Duct adapter provided to support ducts
prior to setting the unit.
4. Set the Unit: Lift unit to a point directly above the
curb and duct openings. Guide unit while lowering
to align with duct openings. Roof curbs fit inside
the unit base. Make sure the unit is properly seated
on the curb and is level.
5. Fastening: The installer is responsible for ensuring
that the unit fastening methods are sufficient
to account for the weight and size of these
additional modules.
Curb Outside Dimensions and Weights
W
Unit Size
L
ERV-10
42 75
30 5
ERV-20
59 25
48 25
ERV-45
63 75
63 75
ERV-90
120 5
80 5
ERV-120
142 25
All dimensions are in inches
10
Energy Recovery Ventilator
1 Fan
Wheel
Dia.
1 Fan
Wheel
L
Dia.
Turning
Vanes
Turning
Vanes
GOOD
Curb Weight
Curb
W
(lbs.)
Height
50
75
125
520
93
700
Side of Unit
Curb Cap Details for Factory Supplied Roof Curbs
Unit Size
ERV-10
1 88
ERV-20
1 88
ERV-45
1 88
ERV-90
1 81
ERV-120
1 94
All dimensions are in inches
Ductwork Connections
Examples of poor and good fan-to-duct connections
are shown. 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
1 Fan
Wheel
Dia.
low airflow and other
system effects.
Recommended Discharge Duct Size and Length
Unit Size Blower Size Duct Size Straight Duct Length
ERV-10
ERV-20
ERV-45
1.2
ERV-90L
1.0
ERV-90H
0.8
ERV-120
1 Fan
Wheel
Dia.
All dimensions shown in inches
0.6
• Recommended duct sizes are based on velocities across the
0.4
cfm range of each model at approximately 800 feet per minute
(FPM) at minimum airflow and up to 1600 fpm at maximum
POOR
GOOD
0.2
POOR
airflow Recommended duct sizes are only intended to be a
guide and may not satisfy the requirements of the project
0.0
0
Refer to plans for appropriate job specific duct size and/or
14
velocity limitations
• Straight duct lengths were calculated based on 100% effective
14
duct length requirements as prescribed in AMCA Publication
14
201 Calculated values have been rounded up to nearest foot
12
12
Base
A
B
C
D
E
1-inch Insulation
Roof Curb
A
B
C
2
1
2
1
2
1
Turning
Vanes
4
1 75
4 13
1 94
POOR
POOR
GOOD
POOR
Length of Straight Duct
GOOD
10
9 x 9
10
14 x 14
SYSTEM EFFECT FACTOR CURVES
12
20 x 20
SYSTEM EFFECT FACTOR CURVES
1.2
15
28 x 28
1.0
18
32 x 32
0.8
20
34 x 34
0.6
0.4
0.2
0.0
0
5
10
5
10
15
20
25
30
35
FPM X 100
OUTLET VELOCITY
D
E
0 80
0 84
0 57
0 75
Turning
0 81
0 75
Vanes
1
0 75
1 13
0 63
GOOD
POOR
Length of Straight Duct
GOOD
3
4
5
7
8
9
15
20
25
30
35
40
40
45
FPM X 100
OUTLET VELOCITY
®
45
Hide quick links:
Advertisement
Table of Contents
