Gas Piping; Nominal Manifold Pressure - High Fire; Nominal Manifold Pressure - Low Fire - Johnson Controls TM9V C Series Installation Manual

5750149-UIM-D-1219
FIGURE 12: Gas Piping
HIGH ALTITUDE GAS ORIFICE CONVERSION
This furnace is constructed at the factory for natural gas-fired operation
at 0 – 7,999 feet (0 – 2,438 m) above sea level.
The manifold pressure must be changed in order to maintain proper
and safe operation when the furnace is installed in a location where the
altitude is greater than 7,999 feet (2,438 m) above sea level. Refer to
Table 4 for proper manifold pressure settings.
Table 4: Nominal Manifold Pressure - High Fire
Manifold Pressures
Gas Heating Value
0-7999
(BTU/cu ft.)
in. w.c.
800 3.5
850 3.5
900 3.5
950 3.5
1000 3.5
1050 3.5
1100 3.2
2500 (LP) 9.8
Table 5: Nominal Manifold Pressure - Low Fire
Manifold Pressures
Gas Heating Value
0-7999
(BTU/cu ft.)
in. w.c.
800 1.7
850 1.7
900 1.7
950 1.7
1000 1.6
1050 1.5
1100 1.3
2500 (LP) 4.1
10
Altitude (feet)
8000-8999 9000-9999
in. w.c. in. w.c.
3.5 3.5
3.5 3.5
3.5 3.5
3.5 3.3
3.2 2.9
2.9 2.7
2.7 2.4
8.2 7.5
Altitude (feet)
8000-8999 9000-9999
in. w.c. in. w.c.
1.7 1.7
1.7 1.7
1.7 1.7
1.7 1.5
1.5 1.4
1.4 1.3
1.2 1.1
3.8 3.5
HIGH ALTITUDE PRESSURE SWITCH CONVERSION
For installation where the altitude is less than 5,000 feet (1,524m), it is
not required that the pressure switch be changed unless you are in an
area subject to low pressure inversions.
Manifold Pressures
Gas Heating Value
0-2437
(MJ/cu m)
kPa
29.8 0.87
31.7 0.87
33.5 0.87
35.4 0.87
37.3 0.87
39.1 0.87
41.0 0.80
93.2 (LP) 2.44
Manifold Pressures
Gas Heating Value
0-2437
(MJ/cu m)
kPa
29.8 0.42
31.7 0.42
33.5 0.42
35.4 0.42
37.3 0.41
39.1 0.37
41.0 0.34
93.2 (LP) 1.03
Altitude (m)
2438-2742 2743-3048
kPa kPa
0.87 0.87
0.87 0.87
0.87 0.87
0.87 0.81
0.80 0.73
0.73 0.67
0.66 0.61
2.03 1.86
Altitude (m)
2438-2742 2743-3048
kPa kPa
0.42 0.42
0.42 0.42
0.42 0.42
0.42 0.38
0.37 0.34
0.34 0.31
0.31 0.28
0.95 0.87
Johnson Controls Ducted Systems