72
Table 21 -- Orifice Size and Manifold Pressure (in. w.c.) for Gas Input Rate (Cont.)
S
A
G
L
A
R
U
T
A
N
F
O
Y
T
I
V
A
R
G
C
I
F
I
C
E
P
S
S
A
G
.
G
V
A
HEAT VALUE
0.58
0.60
0.62
0.64
AT ALTITUDE
Orifice
Manifold
Orifice
Manifold
Orifice
Manifold
Orifice
Manifold
(Btu/cu ft)
No.
Pressure
No.
Pressure
No.
Pressure
No.
Pressure
ALTITUDE
RANGE
ft (m)
SINGLE-STAGE FURNACE
(TABULATED DATA BASED ON 20,000 BTUH PER BURNER, DERATED 2%/1000 FT (305M) ABOVE SEA LEVEL)
650
42
3.4
42
3.5
42
3.6
42
3.7
7001
675
43
3.8
42
3.2
42
3.3
42
3.4
(2134)
700
43
3.5
43
3.7
43
3.8
42
3.2
725
44
3.8
43
3.4
43
3.5
43
3.6
750
44
3.5
44
3.7
44
3.8
43
3.4
8000
775
44
3.3
44
3.4
44
3.5
44
3.7
(2438)
800
44
3.1
44
3.2
44
3.3
44
3.4
825
44
2.9
44
3.0
44
3.1
44
3.2
625
42
3.4
42
3.5
42
3.6
42
3.7
8001
650
43
3.8
42
3.2
42
3.3
42
3.4
(2439)
675
43
3.5
43
3.6
43
3.7
42
3.2
700
44
3.7
43
3.4
43
3.5
43
3.6
725
44
3.5
44
3.6
44
3.7
44
3.8
9000
750
44
3.3
44
3.4
44
3.5
44
3.6
(2743)
775
44
3.0
44
3.2
44
3.3
44
3.4
9001
600
42
3.3
42
3.4
42
3.6
42
3.7
(2744)
625
43
3.7
42
3.2
42
3.3
42
3.4
650
43
3.5
43
3.6
43
3.7
43
3.8
675
44
3.7
44
3.8
43
3.4
43
3.5
10000
700
44
3.4
44
3.5
44
3.7
44
3.8
(3048)
725
44
3.2
44
3.3
44
3.4
44
3.5
* Orifice numbers shown in
BOLD
are factory-installed.
to
to
to
U.
S
.A.
On
ly
U.
S
.A.
On
ly
U.
S
.A.
On
ly
A11253B
922SA
