Carrier DOWNFLOW HORIZONTAL 2-SPEED - Manual (Page 18)

Table 10—Model 58TMA Orifice Size and Manifold Pressure for Correct Input
(Tabulated Data Based on 21,000 Btuh High Heat/13,500 Btuh Low Heat per Burner,
Derated 4% 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.
and
Canada
850 42 3.3/1.4 42 3.4/1.4 42 3.5/1.5 42 3.7/1.5 42 3.8/1.6
875 43 3.8/1.6 42 3.2/1.3 42 3.3/1.4 42 3.5/1.4 42 3.6/1.5
900 43 3.6/1.5 43 3.7/1.5 42 3.2/1.3 42 3.3/1.3 42 3.4/1.4
0 925 43 3.4/1.4 43 3.5/1.5 43 3.6/1.5 43 3.8/1.6 42 3.2/1.3
950 44 3.7/1.5 44 3.8/1.6 43 3.5/1.4 43 3.6/1.5 43 3.7/1.5
to 975 44 3.5/1.5 44 3.6/1.5 44 3.8/1.6 43 3.4/1.4 43 3.5/1.4
1000 44 3.3/1.4 44 3.5/1.4 44 3.6/1.5 44 3.7/1.5 44 3.8/1.6
2000 1025 44 3.2/1.3 44 3.3/1.4 44 3.4/1.4 44 3.5/1.5 44 3.6/1.5
1050 45 3.7/1.5 45 3.8/1.6 44 3.2/1.3 44 3.4/1.4 44 3.5/1.4
1075 46 3.7/1.5 46 3.8/1.6 45 3.7/1.5 44 3.2/1.3 44 3.3/1.4
1100 46 3.5/1.5 46 3.6/1.5 46 3.8/1.6 45 3.7/1.5 45 3.8/1.6
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.
and
Canada
U.S.A. 775 43 3.7/1.5 42 3.2/1.3 42 3.3/1.4 42 3.4/1.4 42 3.5/1.4
Altitudes 800 43 3.5/1.4 43 3.6/1.5 43 3.7/1.5 42 3.2/1.3 42 3.3/1.3
2001 825 44 3.8/1.6 43 3.4/1.4 43 3.5/1.5 43 3.6/1.5 43 3.7/1.5
to 850 44 3.6/1.5 44 3.7/1.5 44 3.8/1.6 43 3.4/1.4 43 3.5/1.5
3000 875 44 3.4/1.4 44 3.5/1.4 44 3.6/1.5 44 3.7/1.5 44 3.8/1.6
or 900 44 3.2/1.3 44 3.3/1.4 44 3.4/1.4 44 3.5/1.4 44 3.6/1.5
Canada 925 46 3.8/1.6 45 3.8/1.6 44 3.2/1.3 44 3.3/1.4 44 3.4/1.4
Altitudes 950 46 3.6/1.5 46 3.7/1.5 45 3.7/1.5 45 3.8/1.6 44 3.2/1.3
2000 975 46 3.4/1.4 46 3.5/1.5 46 3.7/1.5 46 3.8/1.6 45 3.7/1.5
to 1000 47 3.7/1.5 47 3.8/1.6 46 3.5/1.4 46 3.6/1.5 46 3.7/1.5
4500 1025 47 3.5/1.5 47 3.6/1.5 47 3.8/1.6 46 3.4/1.4 46 3.5/1.5
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
750 43 3.5/1.4 43 3.6/1.5 43 3.7/1.5 42 3.2/1.3 42 3.3/1.4
775 44 3.8/1.6 43 3.4/1.4 43 3.5/1.4 43 3.6/1.5 43 3.7/1.5
800 44 3.5/1.5 44 3.7/1.5 44 3.8/1.6 43 3.4/1.4 43 3.5/1.4
3001 825 44 3.3/1.4 44 3.4/1.4 44 3.5/1.5 44 3.7/1.5 44 3.8/1.6
850 45 3.8/1.6 44 3.2/1.3 44 3.3/1.4 44 3.4/1.4 44 3.6/1.5
to 875 46 3.7/1.5 45 3.7/1.5 44 3.2/1.3 44 3.3/1.3 44 3.4/1.4
900 46 3.5/1.5 46 3.7/1.5 46 3.8/1.6 45 3.7/1.5 44 3.2/1.3
4000 925 47 3.8/1.6 46 3.5/1.4 46 3.6/1.5 46 3.7/1.5 46 3.8/1.6
950 47 3.6/1.5 47 3.7/1.5 46 3.4/1.4 46 3.5/1.5 46 3.6/1.5
975 47 3.4/1.4 47 3.5/1.5 47 3.7/1.5 47 3.8/1.6 46 3.4/1.4
1000 48 3.7/1.5 48 3.8/1.6 47 3.5/1.4 47 3.6/1.5 47 3.7/1.5
* For 125-20 size only, input is 20,500 Btuh for high fire. Deduct 0.1-in. from manifold pressure shown in table. Change orifice size if manifold pressure falls below 3.2-in.
wc.
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