36
440 01 1024 01
Specifications are subject to change without notice
Table 11
NATURAL GAS MANIFOLD PRESSURE (in wc)
FOR THE 40k, 60k & 80k BTUH MODEL AND ALTERNATE INPUT MODELS
20,000 BTU per burner
HEATING
VALUE
at ALTITUDE
BTU/CU. FT.
MEAN ELEVATION FEET ABOVE SEA LEVEL
0 to
2000
2001 to
3000
3001 to
4000
4001 to
5000
5001 to
6000
6001 to
7000
7001 to
8000
Orifice
No.
Manifold
Pressure
Orifice
No.
Manifold
Pressure
Orifice
No.
Manifold
Pressure
Orifice
No.
Manifold
Pressure
Orifice
No.
Manifold
Pressure
Orifice
No.
Manifold
Pressure
Orifice
No.
Manifold
Pressure
700
----
----
----
----
----
----
----
----
----
----
----
----
42
3.6
725
----
----
----
----
----
----
----
----
----
----
42
3.5
42
3.4
750
----
----
----
----
----
----
----
----
----
----
42
3.3
42
3.2
775
----
----
----
----
----
----
----
----
41
2.9
43
3.7
43
3.6
800
----
----
----
----
----
----
42
3.1
43
3.6
43
3.5
43
3.4
825
----
----
----
----
43
3.7
43
3.6
43
3.4
43
3.3
44
3.6
850
----
----
----
----
43
3.5
43
3.4
44
3.7
44
3.6
44
3.4
875
----
----
43
3.4
43
3.3
44
3.6
44
3.5
44
3.4
44
3.2
900
----
----
44
3.7
44
3.6
44
3.4
44
3.3
44
3.2
44
3.1
925
44
3.7
44
3.5
44
3.4
44
3.2
44
3.1
45
3.6
45
3.5
950
44
3.5
44
3.3
44
3.2
44
3.1
45
3.6
45
3.5
45
3.3
975
44
3.3
44
3.1
45
3.7
45
3.5
45
3.4
45
3.3
45
3.2
1000
44
3.2
45
3.6
45
3.5
45
3.4
45
3.2
45
3.1
46
3.1
1050
46
3.6
45
3.3
45
3.2
45
3.1
46
3.1
----
----
----
----
1100
46
3.3
45
3.0
46
3.0
46
2.9
----
----
----
----
----
----
Conversion: 1 in wc = .25 kPa
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--2006/NFPA 54--2006 or National Standard of Canada, Natural Gas And Propane Installation Code CSA B149.1--05.
Table 12
PROPANE GAS MANIFOLD PRESSURE (in wc)
FOR THE 40k, 60k & 80k BTUH MODEL AND ALTERNATE INPUT MODELS
20,000 BTU per burner
HEATING VALUE
at ALTITUDE
BTU/CU. FT.
MEAN ELEVATION FEET ABOVE SEA LEVEL
0 to
2000
2001 to
3000
3001 to
4000
4001 to
5000
5001 to
6000
6001 to
7000
7001 to
8000
2500
10.0
8.9
8.4
10.0
10.0
10.0
10.0
Orifice Size
#55
#55
#55
#56
#56
#56
#56
Conversion: 1 in wc = .25 kPa
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--2006/NFPA 54--2006 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 9
,
Table 10
,
Table 11
and
Table 12
.
The burner orifice part nos. are as follows:
Orifice #41
1096942
Orifice #42
1011351
Orifice #43
1011377
Orifice #44
1011352
Orifice #45
1011353
Orifice #46
1011744
Orifice #47
1011378
Orifice #48
1113201
Orifice #49
1113202
Orifice #54
1011376
Orifice #55
1011354
Orifice #56
1011355
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%
(Propane) for each 1000
′
above sea level in the USA. In
Canada, the input rating must be derated 5% (natural) or
10% (Propane) for each 1000
′
above sea level. See
Table 11
or
Table 12
for required high altitude input rate.
2. For operation with natural gas at altitudes above 2,000
′
,
orifice change and/or manifold pressure adjustments may
be required for the gas supplied. First consult your local gas
supplier, then refer to
Table 9
for required pressure change
and/or orifice change for high altitudes
.
3. For operation with Propane gas, gas orifices
MUST
be
changed and manifold pressure
MUST
be
maintained
as
per
Table 10.
Orifices can be ordered through our
distributor.
(See Figure 39)
High Altitude Input Rate =
Nameplate Sea Level Input Rate x (Multiplier) [USA]
Elevation
High Altitude Multiplier
Natural Gas
Propane Gas
2001
′
- 3000
′
0.95
0.90
3001
′
- 4000
′
0.93
0.86
4001
′
- 5000
′
0.91
0.82
5001
′
- 6000
′
0.89
0.78
6001
′
- 7000
′
0.87
0.74
7001
′
- 8000
′
0.85
0.70
*
Based on mid--range of elevation.
4. In cases where
Table 9
or
Table 10
is not applicable, eg.
alternate input rate application, refer to
Table 11
or
Table 12
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.
In Canada, provincial codes may govern installation of switch.
Check with governing authorities.
