International comfort products N9MP1 Installation Instructions Manual page 35

NATURAL GAS MANIFOLD PRESSURE (² ² ² ² w.c.)
Table 9
FOR THE 80,000 BTUH MODEL AND ALTERNATE INPUT MODELS
HEATING HEATING
0 to
VALUE
2000
at ALTITUDE at ALTITUDE
Orifice Manifold
BTU/CU. FT.
No. Pressure
700 ---- ----
725 ---- ----
750 ---- ----
775 ---- ----
800 ---- ----
825 ---- ----
850 ---- ----
875 ---- ----
900 ---- ----
925 44 3.7
950 44 3.5
975 44 3.3
1000 44 3.2
1050 44 2.9
1100 46 3.3
NOTE: Natural gas data is based on 0.60 specific gravity. For fuels with different specific gravity consult the National Fuel Gas Code ANSI
Z223.1--2002/NFPA 54--2002 or National Standard of Canada, Natural Gas And Propane Installation Code CSA B149.1--05.
LPG or PROPANE GAS MANIFOLD PRESSURE (² ² ² ² w.c.)
Table 10
FOR THE 80,000 BTUH MODEL AND ALTERNATE INPUT MODELS
HEATING VALUE
at ALTITUDE
BTU/CU. FT.
2500
Orifice Size
NOTE: Propane data is based on 1.53 specific gravity. For fuels with different specific gravity consult the National Fuel Gas Code ANSI Z223.1--2002/NFPA
54--2002 or National Standard Of Canada, Natural Gas And Propane Installation Code CSA B149.1--05.
NOTE: The derating of these furnaces at 2% (Natural Gas) and 4% (Propane Gas) has been tested and design--certified by CSA.
In Canada, the input rating must be derated 5% (Natural Gas) and 10% (Propane Gas) for altitudes of 2,000 to 4,500 above sea level. Use
the 2001 to 3000 column in Table 7, Table 8, Table 9 and Table 10.
General Derating Rules
1. These furnaces may be used at full input rating when
installed at altitudes up to 2,000¢. When installed above
2,000¢, the input must be decreased 2% (natural) or 4% (LP)
for each 1000¢ above sea level in the USA. In Canada, the
input rating must be derated 5% (natural) or 10% (LP) for
each 1000¢ above sea level. See Table 9 or Table 10 for re-
quired high altitude input rate.
2. For operation with natural gas at altitudes above 2,000¢, ori-
fice change and/or manifold pressure adjustments may be
required for the gas supplied. First consult your local gas
supplier, then refer to Table 7 for required pressure change
and/or orifice change for high altitudes.
3. For operation with LP gas, gas orifices MUST be changed
and manifold pressure MUST be maintained
Table 8. Orifices can be ordered through our distributor.
(See Figure 38)
440 01 1021 01
MEAN ELEVATION FEET ABOVE SEA LEVEL
2001 to 3001 to
3000 4000
Orifice Manifold Orifice Manifold
No. Pressure No. Pressure
---- ---- ----
---- ---- ----
---- ---- ----
---- ---- ----
---- ---- ----
---- ---- 44
---- ---- 44
44 3.5 44
44 3.3 44
44 3.2 44
44 3.0 44
44 2.8 44
44 2.7 44
44 2.5 48
45 3.7 48
MEAN ELEVATION FEET ABOVE SEA LEVEL
0 to 2001 to
2000 3000
10.0 8.9
#55 #55
as per
4001 to 5001 to
5000
Orifice Manifold Orifice
No. Pressure No.
---- ---- ---- ----
---- ---- ---- ----
---- ---- ---- ----
---- ---- ---- 44
---- 44 3.6 44
3.7 44 3.4 44
3.5 44 3.2 44
3.3 44 3.0 44
3.1 44 2.8 44
2.9 44 2.7 44
2.8 44 2.6 44
2.6 44 2.4 48
2.5 47 3.3 48
3.7 48 3.4 49
3.4 49 3.7 ----
3001 to 4001 to
4000 5000
8.4 10.0
#55 #56
High Altitude Input Rate =
Nameplate Sea Level Input Rate x (Multiplier) [USA]
Elevation Elevation
2001¢ - 3000¢
3001¢ - 4000¢
4001¢ - 5000¢
5001¢ - 6000¢
6001¢ - 7000¢
7001¢ - 8000¢
* Based on mid--range of elevation.
4. In cases where Table 7 or Table 8 is not applicable, eg. al-
ternate input rate application, refer to Table 9 or Table 10
for required high altitude input rate.
High Altitude Air Pressure Switch
Altitudes over 4,000¢ may require a different air pressure switch
than the one installed at the factory. Check parts list for pressure
switch and consult your distributor for part number and availability.
6001 to
6000 7000
Manifold Orifice Manifold
Pressure No. Pressure
---- ---- ----
---- 44 3.7
---- 44 3.5
3.5 44 3.2
3.3 44 3.0
3.1 44 2.9
2.9 44 2.7
2.8 44 2.5
2.6 44 2.4
2.5 48 3.7
2.4 48 3.5
3.7 48 3.4
3.5 48 3.2
3.7 ---- ----
---- ---- ----
5001 to 6001 to
6000 7000
10.0 10.0
#56 #56
High Altitude Multiplier
Natural Gas
0.95
0.93
0.91
0.89
0.87
0.85
7001 to
8000
Orifice Manifold
No. Pressure
44 3.7
44 3.4
44 3.2
44 3.0
44 2.8
44 2.6
44 2.5
47 3.4
48 3.6
48 3.4
48 3.3
49 3.6
49 3.4
---- ----
---- ----
7001 to
8000
10.0
#56
LP Gas
0.90
0.86
0.82
0.78
0.74
0.70
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