Manual 2100-365
Page 24
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
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.
TABLE 7
NATURAL GAS DERATE CAPACITIES
FOR ALL MODELS
d
e
t
a
R
G
W
t
u
p
n
I
a
e
S
l
e
v
e
L
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
,
7
0
0
0
,
8
0
0
0
,
9
0
0
0
,
0
1
0
0
5
,
0
4
0
0
0
,
5
4
0
0
5
,
0
4
0
0
0
,
5
4
4
0
2
,
9
3
0
6
5
,
3
4
8
0
9
,
7
3
0
2
1
,
2
4
2
1
6
,
6
3
0
8
6
,
0
4
0
4
6
,
5
3
0
0
6
,
9
3
2
9
9
,
4
3
0
8
8
,
8
3
2
8
1
,
4
3
0
8
9
,
7
3
6
9
6
,
3
3
0
4
4
,
7
3
8
4
0
,
3
3
0
2
7
,
6
3
3
4
6
,
2
3
0
7
2
,
6
3
6
7
0
,
2
3
0
4
6
,
5
3
0
5
7
,
0
6
0
0
5
,
7
6
0
5
7
,
0
6
0
0
5
,
7
6
6
0
8
,
8
5
0
4
3
,
5
6
2
6
8
,
6
5
0
8
1
,
3
6
8
1
9
,
4
5
0
2
0
,
1
6
0
6
4
,
3
5
0
0
4
,
9
5
8
8
4
,
2
5
0
2
3
,
8
5
3
7
2
,
1
5
0
7
9
,
6
5
4
4
5
,
0
5
0
6
1
,
6
5
2
7
5
,
9
4
0
8
0
,
5
5
5
6
9
,
8
4
5
0
4
,
4
5
4
1
1
,
8
4
0
6
4
,
3
5
0
0
0
,
5
7
0
0
0
,
1
8
0
0
0
,
5
7
0
0
0
,
1
8
0
0
6
,
2
7
8
0
4
,
8
7
0
0
2
,
0
7
6
1
8
,
5
7
0
0
8
,
7
6
4
2
2
,
3
7
0
0
0
,
6
6
0
8
2
,
1
7
0
0
8
,
4
6
4
8
9
,
9
6
0
0
3
,
3
6
4
6
3
,
8
6
0
0
4
,
2
6
2
9
3
,
7
6
0
0
2
,
1
6
6
9
0
,
6
6
0
5
4
,
0
6
6
8
2
,
5
6
0
0
4
,
9
5
2
5
1
,
4
6
0
0
0
,
0
9
0
0
0
,
0
0
1
0
0
0
,
0
9
0
0
0
,
0
0
1
0
2
1
,
7
8
0
0
8
,
6
9
0
4
2
,
4
8
0
0
6
,
3
9
0
6
3
,
1
8
0
0
4
,
0
9
0
0
2
,
9
7
0
0
0
,
8
8
0
6
7
,
7
7
0
0
4
,
6
8
0
6
9
,
5
7
0
0
4
,
4
8
0
8
8
,
4
7
0
0
2
,
3
8
0
4
4
,
3
7
0
0
6
,
1
8
0
4
5
,
2
7
0
0
6
,
0
8
0
8
2
,
1
7
0
0
2
,
9
7
0
0
5
,
2
1
1
0
0
0
,
5
2
1
0
0
5
,
2
1
1
0
0
0
,
5
2
1
0
0
9
,
8
0
1
0
0
0
,
1
2
1
0
0
3
,
5
0
1
0
0
0
,
7
1
1
0
0
7
,
1
0
1
0
0
0
,
3
1
1
0
0
0
,
9
9
0
0
0
,
0
1
1
0
0
2
,
7
9
0
0
0
,
8
0
1
0
5
9
,
4
9
0
0
5
,
5
0
1
0
0
6
,
3
9
0
0
0
,
4
0
1
0
0
8
,
1
9
0
0
0
,
2
0
1
5
7
6
,
0
9
0
5
7
,
0
0
1
0
0
1
,
9
8
0
0
0
,
9
9
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 16, "Manifold Pressure Adjustment" is
considered to be an improper procedure.
Above 6,000 feet elevation orifice changes are
required, and capacity reductions are a function of
altitude impact and orifice change. Pressure switch
change is required above 6,000 feet elevation. For
Natural Gas see the Altitude Table 7 below and the
Orifice Tables 8 and 8A on following pages.
Summary of Contents for WG241
Page 12: ...Manual 2100 365 Page 9 FIGURE 2 MOUNTING INSTRUCTIONS FOR WG24 WG30 AND WG36 MIS 1681...
Page 13: ...Manual 2100 365 Page 10 FIGURE 2A MOUNTING INSTRUCTIONS FOR WG42 WG48 AND WG60 MIS 1472...
Page 16: ...Manual 2100 365 Page 13 FIGURE 6 COMMON WALL MOUNTING INSTALLATIONS MIS 1474...
Page 22: ...Manual 2100 365 Page 19 FIGURE 11 LOW VOLTAGE WIRING MIS 1719...
Page 23: ...Manual 2100 365 Page 20 FIGURE 12 GAS PIPE CONNECTION MIS 1683...
Page 33: ...Manual 2100 365 Page 30 26 LIGHTING AND SHUTDOWN INSTRUCTIONS FIGURE 15 INSTRUCTION LABEL...
Page 50: ...Manual 2100 365 Page 47 WG241 A 230 208 60 1...
Page 51: ...Manual 2100 365 Page 48 WG241 A 230 208 60 1...
Page 52: ...Manual 2100 365 Page 49 WG241 B 230 208 60 3...
Page 53: ...Manual 2100 365 Page 50 WG241 B 230 208 60 3...
Page 54: ...Manual 2100 365 Page 51 WG241 C 460 60 3...
Page 55: ...Manual 2100 365 Page 52 WG241 C 460 60 3...
Page 56: ...Manual 2100 365 Page 53 WG301 A WG361 A 230 208 60 1...
Page 57: ...Manual 2100 365 Page 54 WG301 A WG361 A 230 208 60 1...
Page 58: ...Manual 2100 365 Page 55 WG301 B WG361 B 230 208 60 3...
Page 59: ...Manual 2100 365 Page 56 WG301 B WG361 B 230 208 60 3...
Page 60: ...Manual 2100 365 Page 57 WG301 C WG361 C 460 60 3...
Page 61: ...Manual 2100 365 Page 58 WG301 C WG361 C 460 60 3...
Page 62: ...Manual 2100 365 Page 59 WG422 A 230 208 60 1...
Page 63: ...Manual 2100 365 Page 60 WG422 A 230 208 60 1...
Page 64: ...Manual 2100 365 Page 61 WG422 B 230 208 60 3...
Page 65: ...Manual 2100 365 Page 62 WG422 B 230 208 60 3...
Page 66: ...Manual 2100 365 Page 63 WG422 C 460 60 3...
Page 67: ...Manual 2100 365 Page 64 WG422 C 460 60 3...
Page 68: ...Manual 2100 365 Page 65 WG481 A WG601 A 230 208 60 1...
Page 69: ...Manual 2100 365 Page 66 WG481 A WG601 A 230 208 60 1...
Page 70: ...Manual 2100 365 Page 67 WG481 B WG601 B 230 208 60 3...
Page 71: ...Manual 2100 365 Page 68 WG481 B WG601 B 230 208 60 3...
Page 72: ...Manual 2100 365 Page 69 WG481 C WG601 C 460 60 3...
Page 73: ...Manual 2100 365 Page 70 WG481 C WG601 C 460 60 3...