Roof Curb Mounting
Roof curb details including duct location dimensions, are available on Roof Curb Assembly Instructions, Part Number 472119.
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). 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.Install Insulation:
Insulation is not included from the factory.
5.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.
Curb Outside Dimensions and Weights
Curb Outside Dimensions - continued
Unit Side
1.895 | Unit Base |
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4.844 |
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(Insulation not included) | |||
Roof Curb
1.549 
0.775
Curb Cap Details for Factory Supplied Roof Curbs
Ductwork Connections
Examples of poor and good
should be directed straight or curve
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GOOD
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Unit Size | L | W | LF | WF | Curb Weight | |
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61.125 | 40.375 | 64.875 | 44.125 | 93 | ||
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63.375 | 48.5 | 67.125 | 52.25 | 106 | ||
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67.375 | 55.5 | 71.125 | 59.25 | 120 | ||
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78.25 | 65.5 | 82 | 69.188 | 148 | ||
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All dimensions are in inches. Weights are for
Recommended Discharge Duct Size and Length
Model | Blower Size | Duct Size | Straight Duct Length |
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9 | 14 x 14 | 36 | |
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10 | 20 x 20 | 36 | |
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12 | 20 x 20 | 36 | |
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15 | 28 x 28 | 60 | |
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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.
Model ERVe Energy Recovery Unit 5
