Roof curb mounting, Ductwork connections, Curb dimensions and weights – Greenheck Fan PVE-35 User Manual

Page 6

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6

Model PVe Heat Recovery Unit

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 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.

Curb Cap Details for Factory Supplied Roof Curbs

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.

1 Fan

Wheel

Dia.

1 Fan

Wheel

Dia.

Rota

tio

n

Rota

tio

n

R

ot

ation

R

ot

ation

Length of Straight Duct

GOOD

POOR

GOOD

POOR

GOOD

POOR

Turning

Vanes

Turning

Vanes

SYSTEM EFFECT FACTOR CURVES

FPM X 100

OUTLET VELOCITY

0 5 10 15 20 25 30 35 40 45

1.2

1.0

0.8

0.6

0.4

0.2

0.0

S

TA

TIC PRESSURE LOSS

CUR

VE

1

CUR

VE

2

CUR

VE

3

CUR

VE 4

L

W

Curb Dimensions and Weights

4.844

1.549

0.775

Insulation Pan

Unit Base

Roof Curb

Dimensions are shown in inches.

1.895

Unit Side

Recommended Discharge Duct Size and Length

Unit Size Blower Size Duct Size Straight Duct Length

PVe-20

9

14 x 14

36

PVe-35

10

20 x 20

36

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.

1 Fan

Wheel

Dia.

1 Fan

Wheel

Dia.

Rota

tio

n

Rota

tio

n

R

ot

ation

R

ot

ation

Length of Straight Duct

GOOD

POOR

GOOD

POOR

GOOD

POOR

Turning

Vanes

Turning

Vanes

SYSTEM EFFECT FACTOR CURVES

FPM X 100

OUTLET VELOCITY

0 5 10 15 20 25 30 35 40 45

1.2

1.0

0.8

0.6

0.4

0.2

0.0

S

TA

TIC PRESSURE LOSS

CUR

VE

1

CUR

VE

2

CUR

VE

3

CUR

VE 4

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