Manual
2100-483E
Page
29 of 59
21. STANDARD ORIFICE SIZING AND
HIGH ALTITUDE DERATE
This furnace is shipped with fixed gas orifices for use
with Natural Gas and sized for 1000 BTU/cubic foot
gas. Make sure actual gas input does not exceed rating
plate input. You may need to change orifices to get
correct gas input. Whether you do or not depends on
input, and your gas heat value at standard conditions
and elevation. Consult your local gas supplier for gas
heat value and any special derating requirements. See
Section 20 for more information.
At higher altitudes, the density of the air is reduced.
Therefore, for proper combustion, the quantity of gas
TABLE 7
NATURAL GAS DERATE CAPACITIES
FOR ALL MODELS
S
E
I
T
I
C
A
P
A
C
E
T
A
R
E
D
S
A
G
L
A
R
U
T
A
N
d
e
t
a
R
G
W
t
u
p
n
I
l
e
v
e
L
a
e
S
0
0
0
1
0
0
0
2
0
0
0
3
0
0
0
4
0
0
0
5
0
0
0
6
0
0
0
,
5
4
0
0
0
,
5
4
0
6
5
,
3
4
0
2
1
,
2
4
0
8
6
,
0
4
0
0
6
,
9
3
0
8
8
,
8
3
0
8
9
,
7
3
0
0
0
,
0
5
0
0
0
,
0
5
0
0
4
,
8
4
0
0
8
,
6
4
0
0
2
,
5
4
0
0
0
,
4
4
0
0
2
,
3
4
0
0
2
,
2
4
0
0
5
,
7
6
0
0
5
,
7
6
0
4
3
,
5
6
0
8
1
,
3
6
0
2
0
,
1
6
0
0
4
,
9
5
0
2
3
,
8
5
0
7
9
,
6
5
0
0
0
,
5
7
0
0
0
,
5
7
0
0
6
,
2
7
0
0
2
,
0
7
0
0
8
,
7
6
0
0
0
,
6
6
0
0
8
,
4
6
0
0
3
,
3
6
0
0
0
,
0
9
0
0
0
,
0
9
0
2
1
,
7
8
0
4
2
,
4
8
0
6
3
,
1
8
0
0
2
,
9
7
0
6
7
,
7
7
0
6
9
,
5
7
0
0
0
,
0
0
1
0
0
0
,
0
0
1
0
0
8
,
6
9
0
0
6
,
3
9
0
0
4
,
0
9
0
0
0
,
8
8
0
0
4
,
6
8
0
0
4
,
4
8
0
0
5
,
2
1
1
0
0
5
,
2
1
1
0
0
9
,
8
0
1
0
0
3
,
5
0
1
0
0
7
,
1
0
1
0
0
0
,
9
9
0
0
2
,
7
9
0
5
9
,
4
9
0
0
0
,
5
2
1
0
0
0
,
5
2
1
0
0
0
,
1
2
1
0
0
0
,
7
1
1
0
0
0
,
3
1
1
0
0
0
,
0
1
1
0
0
0
,
8
0
1
0
0
5
,
5
0
1
burned in the furnace must also be reduced. This is
called derating. This unit must be derated when
installed at altitudes greater than 6,000 feet above sea
level. A high altitude pressure switch must also be
installed for operation above 6,000 feet. High altitude
pressure switch kit number 8620-189 is designed for
this application.
It is the installer’s responsibility to see that the furnace
input rate is adjusted properly. Derating must be
achieved by reducing the size of the main burner
orifices. Derating the furnace by adjusting the manifold
pressure lower than the range specified in the Section
19, “Manifold Pressure Adjustment” is considered to be
an improper procedure.
Summary of Contents for WG3S1-A
Page 11: ...Manual 2100 483E Page 11 of 59 FIGURE 2A MOUNTING INSTRUCTIONS FOR WG3S1 ...
Page 12: ...Manual 2100 483E Page 12 of 59 FIGURE 2B MOUNTING INSTRUCTIONS FOR WG4S1 AND WG5S1 ...
Page 15: ...Manual 2100 483E Page 15 of 59 FIGURE 6 COMMON WALL MOUNTING INSTALLATIONS ...
Page 25: ...Manual 2100 483E Page 25 of 59 FIGURE 11 GAS PIPE CONNECTION ...
