Table 6—Multipoise, Hot Surface Ignition, Variable-Speed, Condensing Furnace Orifice Size
and Manifold Pressure for Correct Input Rate Orifice Size and Manifold Pressure for Correct Input-Continued
(Tabulated Data Based on 20,000 Btuh High Heat/13,000 Btuh Low Heat per Burner
Derated 2% for each 1000 ft Above Sea Level)
ALTITUDE
RANGE
(FT)
AVG GAS
HEAT VALUE
AT ALTITUDE
(BTU/CU FT)
SPECIFIC GRAVITY OF NATURAL GAS
0.58
0.60
0.62
0.64
0.66
Orifice
No.
Manifold
Pressure
High/Low
Orifice
No.
Manifold
Pressure
High/Low
Orifice
No.
Manifold
Pressure
High/Low
Orifice
No.
Manifold
Pressure
High/Low
Orifice
No.
Manifold
Pressure
High/Low
U.S.A.
Only
625
43
3.8/1.6
42
3.3/1.4
42
3.4/1.4
42
3.5/1.5
42
3.6/1.5
650
43
3.5/1.5
43
3.7/1.6
43
3.8/1.6
42
3.2/1.4
42
3.3/1.4
675
44
3.8/1.6
43
3.4/1.4
43
3.5/1.5
43
3.6/1.5
43
3.7/1.6
7001
700
44
3.5/1.5
44
3.6/1.5
44
3.8/1.6
43
3.4/1.4
43
3.5/1.5
725
44
3.3/1.4
44
3.4/1.4
44
3.5/1.5
44
3.6/1.5
44
3.7/1.6
to
750
45
3.7/1.6
45
3.8/1.6
44
3.3/1.4
44
3.4/1.4
44
3.5/1.5
775
45
3.5/1.5
45
3.6/1.5
45
3.7/1.6
45
3.8/1.6
44
3.3/1.4
8000
800
45
3.3/1.4
45
3.4/1.4
45
3.5/1.5
45
3.6/1.5
45
3.7/1.6
825
47
3.6/1.5
45
3.2/1.3
45
3.3/1.4
45
3.4/1.4
45
3.5/1.5
850
47
3.4/1.4
47
3.5/1.5
47
3.7/1.5
45
3.2/1.3
45
3.3/1.4
ALTITUDE
RANGE
(FT)
AVG GAS
HEAT VALUE
AT ALTITUDE
(BTU/CU FT)
SPECIFIC GRAVITY OF NATURAL GAS
0.58
0.60
0.62
0.64
0.66
Orifice
No.
Manifold
Pressure
High/Low
Orifice
No.
Manifold
Pressure
High/Low
Orifice
No.
Manifold
Pressure
High/Low
Orifice
No.
Manifold
Pressure
High/Low
Orifice
No.
Manifold
Pressure
High/Low
U.S.A.
Only
600
43
3.8/1.6
42
3.3/1.4
42
3.4/1.4
42
3.5/1.5
42
3.6/1.5
625
43
3.5/1.5
43
3.6/1.5
43
3.8/1.6
42
3.2/1.4
42
3.3/1.4
8001
650
44
3.7/1.6
43
3.4/1.4
43
3.5/1.5
43
3.6/1.5
43
3.7/1.6
675
44
3.5/1.5
44
3.6/1.5
44
3.7/1.6
44
3.8/1.6
43
3.4/1.5
to
700
44
3.2/1.4
44
3.3/1.4
44
3.4/1.5
44
3.6/1.5
44
3.7/1.6
725
45
3.6/1.5
45
3.8/1.6
44
3.2/1.4
44
3.3/1.4
44
3.4/1.4
9000
750
45
3.4/1.4
45
3.5/1.5
45
3.6/1.5
45
3.8/1.6
44
3.2/1.4
775
45
3.2/1.3
45
3.3/1.4
45
3.4/1.4
45
3.5/1.5
45
3.6/1.5
800
47
3.6/1.5
47
3.7/1.6
45
3.2/1.3
45
3.3/1.4
45
3.4/1.4
ALTITUDE
RANGE
(FT)
AVG GAS
HEAT VALUE
AT ALTITUDE
(BTU/CU FT)
SPECIFIC GRAVITY OF NATURAL GAS
0.58
0.60
0.62
0.64
0.66
Orifice
No.
Manifold
Pressure
High/Low
Orifice
No.
Manifold
Pressure
High/Low
Orifice
No.
Manifold
Pressure
High/Low
Orifice
No.
Manifold
Pressure
High/Low
Orifice
No.
Manifold
Pressure
High/Low
U.S.A.
Only
575
43
3.8/1.6
42
3.2/1.4
42
3.3/1.4
42
3.5/1.5
42
3.6/1.5
600
43
3.5/1.5
43
3.6/1.5
43
3.7/1.6
42
3.2/1.3
42
3.3/1.4
9001
625
44
3.7/1.6
44
3.8/1.6
43
3.5/1.5
43
3.6/1.5
43
3.7/1.6
650
44
3.4/1.4
44
3.5/1.5
44
3.7/1.5
44
3.8/1.6
43
3.4/1.4
to
675
45
3.8/1.6
44
3.3/1.4
44
3.4/1.4
44
3.5/1.5
44
3.6/1.5
700
45
3.6/1.5
45
3.7/1.6
45
3.8/1.6
44
3.3/1.4
44
3.4/1.4
10,000
725
45
3.3/1.4
45
3.4/1.5
45
3.6/1.5
45
3.7/1.6
45
3.8/1.6
750
47
3.7/1.6
45
3.2/1.4
45
3.3/1.4
45
3.4/1.5
45
3.5/1.5
775
47
3.5/1.5
47
3.6/1.5
47
3.7/1.6
45
3.2/1.4
45
3.3/1.4
—21—
