67
Table 19 – Orifice Size and Manifold Pressure (in. w.c.) for Gas Input Rate
26,000 BTUH ONLY
AVG. GAS
HEAT VALUE
AT ALTITUDE
Orifice
Manifold
Orifice
Manifold
Orifice
Manifold
Orifice
Manifold
(Btu/cu ft)
No.
Pressure
No.
Pressure
No.
Pressure
No.
Pressure
900
44
1.8
43
1.7
43
1.7
43
1.8
0
925
44
1.7
44
1.8
43
1.6
43
1.7
(0)
950
44
1.6
44
1.7
44
1.8
44
1.8
975
44
1.6
44
1.6
44
1.7
44
1.7
to
1000
44
1.5
44
1.5
44
1.6
44
1.6
1025
44
1.4
44
1.5
44
1.5
44
1.6
2000
1050
44
1.3
44
1.4
44
1.4
44
1.5
(610)
1075
44
1.3
44
1.3
44
1.4
44
1.4
1100
44
1.2
44
1.3
44
1.3
44
1.4
U.S.A.
800
43
1.7
43
1.8
43
1.8
42
1.6
2001 (611)
825
43
1.6
43
1.7
43
1.7
43
1.8
to
850
44
1.8
44
1.8
43
1.6
43
1.7
3000 (914)
875
44
1.7
44
1.7
44
1.8
44
1.8
900
44
1.6
44
1.6
44
1.7
44
1.7
Canada
925
44
1.5
44
1.5
44
1.6
44
1.6
2001 (611)
950
44
1.4
44
1.5
44
1.5
44
1.6
to
975
44
1.3
44
1.4
44
1.4
44
1.5
4500 (1372)
1000
44
1.3
44
1.3
44
1.4
44
1.4
775
43
1.7
43
1.8
43
1.8
42
1.5
800
44
1.8
43
1.7
43
1.7
43
1.8
3001
825
44
1.7
44
1.8
44
1.8
43
1.7
(915)
850
44
1.6
44
1.7
44
1.7
44
1.8
875
44
1.5
44
1.6
44
1.6
44
1.7
900
44
1.4
44
1.5
44
1.5
44
1.6
4000
925
44
1.4
44
1.4
44
1.5
44
1.5
(1219)
950
44
1.3
44
1.3
44
1.4
44
1.4
750
43
1.7
43
1.7
43
1.8
43
1.8
775
44
1.8
43
1.6
43
1.7
43
1.7
4001
800
44
1.7
44
1.7
44
1.8
43
1.6
(1220)
825
44
1.6
44
1.6
44
1.7
44
1.8
850
44
1.5
44
1.5
44
1.6
44
1.7
to
875
44
1.4
44
1.5
44
1.5
44
1.6
5000
900
44
1.3
44
1.4
44
1.4
44
1.5
(1524)
925
44
1.3
44
1.3
44
1.4
44
1.4
725
43
1.7
43
1.7
43
1.8
43
1.8
5001
750
44
1.8
44
1.8
43
1.7
43
1.7
(1525)
775
44
1.7
44
1.7
44
1.8
44
1.8
800
44
1.6
44
1.6
44
1.7
44
1.7
825
44
1.5
44
1.5
44
1.6
44
1.6
850
44
1.4
44
1.4
44
1.5
44
1.5
6000
875
44
1.3
44
1.3
44
1.4
44
1.4
(1829)
900
44
1.2
44
1.3
44
1.3
44
1.4
675
43
1.8
43
1.8
42
1.5
42
1.6
6001
700
43
1.6
43
1.7
43
1.7
43
1.8
(1830)
725
44
1.7
44
1.8
43
1.6
43
1.7
750
44
1.6
44
1.7
44
1.7
44
1.8
775
44
1.5
44
1.6
44
1.6
44
1.7
7000
800
44
1.4
44
1.5
44
1.5
44
1.6
(2133)
825
44
1.3
44
1.4
44
1.4
44
1.5
850
44
1.3
44
1.3
44
1.4
44
1.4
* Orifice numbers shown in
BOLD
are factory-installed.
U.S.A. Only
U.S.A. Only
to
U.S.A. Only
to
ORIFICE SIZE* AND MANIFOLD PRESSURE (IN WC) FOR GAS INPUT RATE
(TABULATED DATA BASED ON 13,000 BTUH PER BURNER, DERATED 2%/1000 FT (305M) ABOVE SEA LEVEL
ALTITUDE
RANGE
U.S.A. and Canada
U.S.A. and Canada
U.S.A. Only
ft (m)
SPECIFIC GRAVITY OF NATURAL GAS
0.58
0.60
0.62
0.64
to
A150571