Greenheck Fan Complete Guide to Greenheck Roof Curbs for PVE Ventilation Hoods

Roof Curb Mounting

Roof curb assembly and mounting instructions are contained in the Roof Curb Assembly Instructions supplied with Model GKD roof curb.

Rooftop PVe units require curbs to be mounted first, in accordance with their appropriate instructions. Curb unit is to be installed and then duct connections are to be made prior to setting of the unit.

1.Factory Supplied Roof Curbs: Roof curbs are Model GKD. The GKD ships in a knockdown kit (which includes duct adapter) and requires field assembly by others. Assembly instructions are included with the GKD curbs.

2.Install Curb: Locate the assembled curb over roof opening and verify precise location of curb relative to the roof opening, in accordance with dimensions given previously. Fasten curb loosely in place and then shim as needed to ensure a level installation. Tighten roof fastening hardware and then re-check for level. Verify that diagonal dimensions of installed curb are plus or minus 1/8-inch of each other.

3.Install Ductwork: Install needed ductwork in accordance with SMACNA and AMCA guidelines. Duct adapter is provided to support ducts prior to setting the unit.

4.Install Insulation: One-inch deep insulation pans are provided with the curb assembly. Set the insulation pans per instructions and then install insulation in the pans prior to setting the unit. Insulation is not provided by the unit manufacturer, it is to be supplied by others.

5.Set the PVe Unit: Lift unit to a point directly above the curb and duct openings. Guide unit carefully while lowering in order to align with duct openings. The roof curb will seat in a recess in the base of the PVe unit. Verify that the unit is properly seated on the curb and is level.

Unit Side

1.895 Unit Base

Curb Dimensions and Weights

L

W

Unit Size	L	W	Curb Weight
			(lbs.)
PVe-20	99.4	36.8	195
PVe-35	99.4	44.6	216
PVe-45	105.9	56.3	261
PVe-55	111.7	71.3	316

All dimensions are shown in inches.

Ductwork Connections

Examples of poor and good fan-to-

duct connections are
shown below. Airflow								tion
							a
						t
out of the fan should					R	o
be directed straight or
curve the same direction								POOR
as the fan wheel rotates.
Poor duct
installation will				tion	Length of Straight Duct
			a
		t
	R	o
result in low
airflow and other
system effects.					GOOD
Recommended Discharge Duct Size and Length
Unit Size Blower Size				Duct Size Straight Duct Length

4.844

Insulation Pan

PVe-20	9	14 x 14	36
PVe-35	10	20 x 20	36

Roof Curb

1.549

0.775

Dimensions are shown in inches.

Curb Cap Details for Factory Supplied Roof Curbs

6Model PVe Heat Recovery Unit

PVe-45	12	20 x 20	36
PVe-55	15	28 x 28	60

All dimensions are 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.