Thermo Pride OPA Installation And Service Manual page 72

All installations and services must be performed by qualified service personnel.
or an increase in duct size of about 1 inch in diameter.
The pressure drops for the remaining branches of the system must be set. This
includes segment "G"; segments "I" and "J"; and segments "K", "L", and "M". To
balance the system, the pressure drop for each branch must be approximately
equal to the pressure drops of the other branches. For example, segment "G"
must equal segments "D", "E" and "F" combined. Thus,
Likewise for the other branches,
Using the previous technique, duct sizes can be found for all the remaining
segments. The duct sizes adequate for the entire supply system are summarized
in Table 7, below.
Table 7: Required Duct Sizes for the Residence in Example 2
Duct
Segment
N/A - Not Applicable
⎡
. 0 00123174 *
=
D
⎢
D
. 0
⎣
∆ = ∆ + ∆
P P
G D
∆ + ∆ =
P P 0
I J
∆ + ∆ + ∆
P P
K l
Air Circular
Flowrate Duct Dia.
(CFM)
A 120
B 235
C 350
D 392
E 196
F 742
G 56
H 798
I 126
J 231
K 370
L 304
M 157
( )
. 0 2058
⎤
+
. 1 82
5 48 . 75 * 392
⎥
0614
⎦
+ ∆
P P .
E F
1 . in . W . G .
=
P 0 1 . in . W . G . .
m
Air Velocity in
Circular Duct
(in.) (FPM)
7 449
9 532
11 530
10 719
7 733
14 694
3 1141
14 746
5 924
7 864
10 678
9 688
7 587
71
= ≅
. 9 50 in . 10 in , .
Equivalent
Rectangular
Duct Dim.s
(in.)
6 x 6
8 x 8
10 x 10
9 x 9
6 x 6
13 x 13
N/A
13 x 13
N/A
6 x 6
9 x 9
8 x 8
6 x 6