Table9--Model 58MCA Orifice Size and Manifold Pressure for Correct input
For Use with 040 through 120 Size Furnaces Only
(Tabulated Data Based on 20,000 Btuh per Burner, Derated 2% for Each 1000 Ft Above Sea Levem)*
7
o
ALTITUDE
RANGE
(FT)
to
2000
O%
derate
ALTITUDE
RANGE
(FT)
U.S.A.
Altitudes
2001
to
3000
or
Canada
Altitudes
2001
to
4500
5%
derate
ALTITUDE
RANGE
(FT)
3001
to
4000
7%
derate
AVG GAS
NEAT VALUE
AT ALTITUDE
(BTU/CU FT)
850
875
900
925
950
975
1000
1025
i050
i075
ilO0
AVG GAS
NEAT VALUE
AT ALTITUDE
(BTU/CU FT)
775
800
825
850
875
900
925
950
975
iO00
i025
AVG GAS
NEAT VALUE
AT ALTITUDE
(BTUICU FT)
750
775
800
825
850
875
900
925
950
975
i 000
0.58
Orifice Manifold
No. Pressure
43 3.7
43 3.5
44 3.7
44 3.5
44 3.4
44 3.2
45 3.7
45 3.5
45 3.3
45 3.2
47 3.6
SPECIFIC GRAVITY OF NATURAL GAS
0.50 0.52
Orifice Manifold Orifice Manifold
No. Pressure No. Pressure
43 3.8 42 3.2
43 3.6 43 3.7
43 3.4 43 3.5
44 3.7 44 3.8
44 3.5 44 3.6
44 3.3 44 3.4
45 3.8 44 3.2
45 3.5 45 3.7
45 3.4 45 3.5
45 3.3 45 3.4
47 3.7 45 3.2
0.04 0.65
Orifice Manifold Orifice Manifold
No. Pressure No. Pressure
42 3.3 42 3.4
43 3.8 42 3.2
43 3.6 43 3.7
43 3.4 43 3.5
44 3.7 44 3.8
44 3.5 44 3.6
44 3.4 44 3.5
44 3.2 44 3.3
48 3.7 45 3.8
45 3.5 45 3.0
45 3.4 45 3.5
SPECIFIC GRAVITY OF NATURAL GAS
0.58 0.50 0.02
Orifice Manifold Orifice Manifold Orifice Manifotd
No. Pressure No. Pressure No. Pressure
43 3.8 42 3.2 42 3.3
43 3.5 43 3.7 43 3.8
44 3.8 43 3.4 43 3.6
44 3.6 44 3.7 44 3.8
44 3.4 44 3.5 44 3.6
44 3.2 44 3.3 44 3.4
45 3.7 45 3.8 44 3.2
45 3.5 45 3.5 45 3.7
45 3.3 45 3.4 45 3.5
45 3.t 45 3.2 45 3.4
45 3.0 45 3.t 45 3.2
0.64 0.65
Orifice Manifotd Orifice Manifold
No. Pressure No. Pressure
42 3.4 42 3.5
42 3.2 42 3.3
43 3.7 43 3.8
43 3.5 43 3.6
44 3.7 43 3.4
44 3.5 44 3.6
44 3.3 44 3.4
45 3.8 44 3.3
45 3.5 45 3.8
45 3.5 45 3.5
45 3.3 45 3.4
SPECIFIC GRAVITY OF NATURAL GAS
0.58 0.50 0.52
Orifice Manifold Orifice Manifold Orifice Manifold
No. Pressure No. Pressure No. Pressure
43 3.7 43 3.8 42 3.3
43 3.5 43 3.6 43 3.7
44 3.7 43 3.4 43 3.5
44 3.5 44 3.6 44 3.8
44 3.3 44 3.4 44 3.5
45 3.8 44 3.2 44 3.3
45 3.5 45 3.7 45 3.8
45 3.4 45 3.5 45 3.5
45 3.2 45 3.3 45 3.4
45 3.0 45 3.2 45 3.3
45 2.9 45 3.0 45 3.1
0.64 0.65
Orifice Manifold Orifice Manifotd
No. Pressure No. Pressure
42 3.4 42 3.5
43 3.8 42 3.2
43 3.6 43 3.7
43 3.4 43 3.5
44 3.7 44 3.8
44 3.5 44 3.6
44 3.3 44 3.4
45 3.7 44 3.2
45 3.5 45 3.7
45 3.4 45 3.5
45 3.2 45 3.3
Orifice numbers shown in BOLD are factory installed.
Percents of derate are based on midpoint of U.S. altitude ranges.
4O