RT-SVX24Q-EN
181
Figure 137. Natural gas combustion curve (ratio of oxygen to carbon dioxide in percent)
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
Percent Carbon Dioxide
Percent Oxygen
A =
A
Curve Fuel
1,000 BTU per cu ft.
of Natural Gas
Table 63. Recommended manifold pressures and CO
2
levels during furnace operation
2-STAGE MODULATING
MB-
H
FIR-
ING
RAT-
ES
% CO
2
NAT GAS
MANIF
PRESS
“W.C.
%
CO2P-
RO-
PANE
MANIF
PRESS
“W.C.
MB-
H
FIR-
ING
RATE
%
CO2N-
AT GAS
MANIF
PRESS“-
W.C.
%
CO2P-
RO-
PANE
MANIF
PRESS“-
W.C.
850 100% 8.0-9.0 3.0-3.5 9.0-10.0 3.0-3.5 850 100% 8.0-9.0 3.0- 3.5 7.8-8.4 1.7-2.2
510 60% 5.0 -7.0 0.8-0.95 5.0-7.0 1.5-3.0 85 10% 5.0 -7.0 0.8- 0.9.5 2.0-3.0 .1-.2
1100 100% 8.0-9.0 3.0-3.3 9.0-10.0 3.0-3.3 1100 100% 7.0-9.0 .8-.9 8.5-9.5 .5-.75
550 50% 5.0 -7.0 0.8-0.95 5.0-7.0 0.8-0.95 55 5% 1.5-3.0 .05-1.0 1.5-2.5 .02-.04
1800 100% 7.0- 8.0 1.5- 1.8
N/A N/A
1800 100% 7.0-9.0 1.5- 1.8
N/A N/A
900 50% 5.0- 7.0 0.5- 0.7
N/A N/A
90 5% 1.5-3.0 .05-1.0
N/A N/A
2500 100% 7.5- 8.5 2.0- 2.5
N/A N/A
2500 100% 7.0-9.0 2.0- 2.5
N/A N/A
1250 50% 5.0- 7.0 0.5- 0.7
N/A N/A
125 5% 1.5-3.0 .05-1.0
N/A N/A
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