36
Roof Downblast - Exhaust
Belt Drive
GB-
Performance certified is for installation type A: Free inlet, Free outlet. Power rating (BHP) does not include transmission losses. Performance ratings include the effects
of a birdscreen. The sound ratings shown are loudness values in hemispherical sones at 5 ft. (1.5 m) in a hemispherical free field calculated per AMCA Standard 301.
Values shown are for installation type A: free inlet hemispherical sone levels.
Performance certified is for installation type A: Free inlet, Free outlet. Power rating (BHP) does not include transmission losses. Performance ratings include the effects
of a birdscreen. The sound ratings shown are loudness values in hemispherical sones at 5 ft. (1.5 m) in a hemispherical free field calculated per AMCA Standard 301.
Values shown are for installation type A: free inlet hemispherical sone levels.
1
3
⁄4 (44)
Roof Downblast - Exhaust
Belt Drive
GB-240HP
Damper Size = 24 x 24 (610 x 610)
Roof Opening = 26 x 26 (673 x 673)
Shroud Thickness = 0.064 (1.6)
Motor Cover Thickness = 0.040 (1.0)
Curb Cap Thickness = 0.064 (1.6)
^Approximate Unit Weight = 187 lbs. (85 kg)
All dimensions in inches (millimeters). *May be greater depending on
motor. ^Weight shown is largest cataloged Open Drip-Proof motor.
D
O
N
O
T
S
E
L
E
C
T
T
O
T
H
E
L
E
F
T
O
F
T
H
I
S
S
Y
S
T
E
M
C
U
R
V
E
Static Pressure (in. wg)
Static Pressure (Pa)
Volume (cfm x 1000)
3
Volume (m /hr x 1000)
RPM (Belt)
HP
Density 0.075 lb/ft
3
Density 1.2 kg/m
3
*31
1
⁄2
(800)
34
(864)
Motor
HP
Fan
RPM
Static Pressure in Inches wg
0.5 0.625 0.75 1 1.25 1.5 1.75 2 2.25 2.5
240HP
1/2
635
CFM
3035 2586
BHP
0.42 0.41
Sones
8.0 7.6
685
CFM
3475 3147 2693
BHP
0.53 0.53 0.51
Sones
9.4 8.8 8.4
3/4
733
CFM
3877 3603 3272
BHP
0.64 0.65 0.65
Sones
11.0 10.3 9.7
780
CFM
4247 4005 3740 2964
BHP
0.76 0.77 0.78 0.75
Sones
12.7 11.9 11.3 10.3
1 860
CFM
4860 4654 4434 3915 3105
BHP
0.99 1.02 1.04 1.05 0.99
Sones
15.9 15.2 14.3 13.2 12.2
1
1
⁄2
920
CFM
5310 5118 4925 4496 3944
BHP
1.20 1.23 1.25 1.29 1.27
Sones
18.5 17.4 16.6 15.0 13.8
980
CFM
5751 5574 5392 5010 4562 3958
BHP
1.43 1.47 1.49 1.54 1.55 1.52
Sones
22 19.9 19.1 17.2 15.6 14.8
2
1030
CFM
6114 5948 5776 5428 5039 4560 3896
BHP
1.65 1.69 1.72 1.77 1.80 1.80 1.73
Sones
24 23 21 19.6 17.6 16.3 15.7
1080
CFM
6474 6315 6154 5826 5468 5062 4555 3763
BHP
1.89 1.92 1.96 2.02 2.06 2.08 2.05 1.93
Sones
27 26 24 23 20 18.2 17.3 16.7
3
1133
CFM
6853 6702 6550 6237 5914 5560 5133 4588
BHP
2.16 2.20 2.24 2.31 2.36 2.40 2.39 2.35
Sones
29 27 26 24 22 21 19.3 18.7
1240
CFM
7610 7471 7333 7053 6767 6469 6146 5775 5364 4776
BHP
2.80 2.84 2.89 2.97 3.04 3.10 3.14 3.14 3.13 3.04
Sones
31 30 29 28 27 25 24 23 23 22
MAXIMUM BHP AT A GIVEN RPM = (RPM/845)
3
MAXIMUM RPM = 1240
TIP SPEED (ft/min) = RPM x 6.414
MAXIMUM MOTOR FRAME SIZE = 184T
42
3
⁄4
(1086)
5
3
⁄4 (146)
