Carrier 58MTA - Adjustments; Set Gas Input Rate

FURNACE RESTART
With furnace operating, set thermostat below room temperature
and observe that furnace goes off. Set thermostat above room
temperature and observe that furnace restarts.
Step 5—Adjustments
SET GAS INPUT RATE
Furnace gas input rate on rating plate is for installations at altitudes
up to 2000 ft.
In the U.S.A., the input ratings for altitudes above 2000 ft must be
reduced by 2 percent for each 1000 ft above sea level.
In Canada, the input ratings must be derated by 5 percent for
altitudes of 2001 ft to 4500 ft above sea level.
Adjust manifold pressure to obtain input rate.
Furnace input rate must be within ± 2 percent of input on furnace
rating plate adjusted for altitude.
1. Determine Natural Gas Orifice Size And Manifold Pressure
For Correct Input.
TABLE 10—MODEL 58MTA ORIFICE SIZE AND HIGH/LOW-HEAT MANIFOLD PRESSURES
FOR CORRECT INPUTS
FOR USE WITH 060 THROUGH 120 SIZE FURNACES ONLY
(TABULATED DATA BASED ON 20,000/13,000 BTUH PER BURNER, DERATED 2 PERCENT FOR EACH 1000
FT ABOVE SEA LEVEL)*
ALTITUDE
RANGE
(FT)
AVG GAS
HEAT VALUE
(BTU/CU FT)
SPECIFIC GRAVITY OF NATURAL GAS
0.58 0.60 0.62 0.64 0.66
Orifice
no.
Manifold
Pressure
Orifice
no.
Manifold
Pressure
Orifice
no.
Manifold
Pressure
Orifice
no.
Manifold
Pressure
Orifice
no.
Manifold
Pressure
U.S.A. and Canada
0
to
2000
0%
derate
850 43 3.7/1.5 43 3.8/1.6 42 3.2/1.4 42 3.3/1.4 42 3.4/1.4
875 43 3.5/1.5 43 3.6/1.5 43 3.7/1.6 43 3.8/12.6 42 3.2/1.4
900 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
925 44 3.5/1.5 44 3.7/1.6 44 3.8/1.6 43 3.4/1.4 43 3.5/1.5
950 44 3.4/1.4 44 3.5/1.5 44 3.6/1.5 44 3.7/1.6 44 3.8/1.6
975 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
1000 45 3.7/1.6 45 3.8/1.6 44 3.2/1.4 44 3.4/1.4 44 3.5/1.5
1025 45 3.5/1.5 45 3.6/1.5 45 3.7/1.6 44 3.2/1.3 44 3.3/1.4
1050 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
1075 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
1100 47 3.6/1.5 47 3.7/1.6 45 3.2/1.4 45 3.4/1.4 45 3.5/1.5
ALTITUDE
RANGE
(FT)
AVG GAS
HEAT VALUE
(BTU/CU FT)
SPECIFIC GRAVITY OF NATURAL GAS
0.58 0.60 0.62 0.64 0.66
Orifice
no.
Manifold
Pressure
Orifice
no.
Manifold
Pressure
Orifice
no.
Manifold
Pressure
Orifice
no.
Manifold
Pressure
Orifice
no.
Manifold
Pressure
U.S.A. and Canada
U.S.
Altitudes
2001
to
3000
or
Canada
Altitudes
2001
to
4500
5%
derate
775 43 3.8/1.6 42 3.2/1.4 42 3.3/1.4 42 3.4/1.4 42 3.5/1.5
800 43 3.5/1.5 43 3.7/1.5 43 3.8/1.6 42 3.2/1.4 42 3.3/1.4
825 44 3.8/1.6 43 3.4/1.5 43 3.6/1.5 43 3.7/1.5 43 3.8/1.6
850 44 3.6/1.5 44 3.7/1.6 44 3.8/1.6 43 3.5/1.5 43 3.6/1.5
875 44 3.4/1.4 44 3.5/1.5 44 3.6/1.5 44 3.7/1.6 43 3.4/1.4
900 44 3.2/1.4 44 3.3/1.4 44 3.4/1.4 44 3.5/1.5 44 3.6/1.5
925 45 3.7/1.5 45 3.8/1.6 44 3.2/1.4 44 3.3/1.4 44 3.4/1.5
950 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
975 45 3.3/1.4 45 3.4/1.4 45 3.5/1.5 45 3.6/1.5 45 3.8/1.6
1000 47 3.7/1.6 45 3.2/1.4 45 3.4/1.4 45 3.5/1.5 45 3.6/1.5
1025 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
(BTU/CU FT)
SPECIFIC GRAVITY OF NATURAL GAS
0.58 0.60 0.62 0.64 0.66
Orifice
no.
Manifold
Pressure
Orifice
no.
Manifold
Pressure
Orifice
no.
Manifold
Pressure
Orifice
no.
Manifold
Pressure
Orifice
no.
Manifold
Pressure
U.S.A. Only
3001
to
4000
7%
derate
750 43 3.7/1.6 43 3.8/1.6 42 3.3/1.4 42 3.4/1.4 42 3.5/1.5
775 43 3.5/1.5 43 3.6/1.5 43 3.7/1.6 43 3.8/1.6 42 3.2/1.4
800 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
825 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
850 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
875 45 3.8/1.6 44 3.2/1.4 44 3.3/1.4 44 3.5/1.5 44 3.6/1.5
900 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
925 45 3.4/1.4 45 3.5/1.5 45 3.6/1.5 45 3.7/1.6 44 3.2/1.3
950 45 3.2/1.4 45 3.3/1.4 45 3.4/1.5 45 3.5/1.5 45 3.7/1.5
975 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
1000 47 3.5/1.5 47 3.6/1.5 45 3.7/1.6 45 3.2/1.4 45 3.3/1.4
* Orifice numbers shown in shading are factory installed.
NOTE: Percents of derate are based on midpoints of U.S. altitude ranges.
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