Manual 2100-721B
Page
32 of 54
TABLE 11A
Natural Gas Orifice Tables for Models
W24G, W30G and W36G
All other orifice sizes shown are available as individual field-supplied items. See orifice tables below for specifications and number
required.
Factory Standard
Input
Gas Heat* Value
BTU/Cu. Ft.
Up to 6,000' No
Changes Except
for BTU Content
6,001' to 8,000'
Requires Pressure Switch
Change and Orifice
Change Based on BTU
Content
8,001' to 10,000'
Requires Pressure Switch
Change and Orifice Change
Based on BTU Content
25000 BTU
Per Burner
700-749
2.75
2.70
2.60
750-799
2.70
2.60
2.50
800-849
2.60
2.50
2.45
850-899
2.50
2.45
2.35
900-949
2.45
2.35
(2.30)
950-999
2.35
(2.30)
2.25
1000-1049**
(2.30)
2.25
[2.20]
1050-1100
2.25
[2.20]
2.15
Pressure Switch
Standard (.55)
Order 8620-189 High Altitude Pressure Switch Kit (.42)
(2.30) is the standard factory-installed orifice size
[2.20] orifices are shipped with the unit for field-installed
optional 10% derate
Optional
10% Field-
Converted Derate
Gas Heat* Value
BTU/Cu. Ft.
Up to 6,000’ No
Changes Except
for BTU Content
6,001’ to 8,000’
Requires Pressure Switch
Change and Orifice
Change Based on BTU
Content
8,001’ to 10,000’
Requires Pressure Switch
Change and Orifice Change
Based on BTU Content
22250 BTU
Per Burner
700-749
2.60
2.50
2.45
750-799
2.50
2.45
2.40
800-849
2.45
2.40
(2.30)
850-899
2.40
(2.30)
2.25
900-949
(2.30)
2.25
[2.20]
950-999
2.25
[2.20]
2.15
1000-1049**
[2.20]
2.15
2.10
1050-1100
2.15
2.15
2.10
Pressure Switch
Standard (.55)
Order 8620-189 High Altitude Pressure Switch Kit (.42)
[2.20] orifices are shipped with the unit for field-installed optional
10% input rate
(2.30) is the factory-installed orifice size for full rated
input
At standard conditions: 30.00 inches Mercury, 60F, saturated, .60 specific gravity.
All Natural Gas factory orifice sizing and standard input ratings based on nominal 1025 BTU/cu. ft. gas and sea level conditions
*
**
Orifice Size (mm)
Orifice Diameter
2.10
0.0826
2.15
0.0846
2.20
0.0866
2.25
0.0885
2.30
0.0905
2.35
0.0925
2.40
0.0945
No. of Orifices Required Based
on Unit Input Rating
41,000 (2)
45,000 (2)
61,000 (3)
68,000 (3)
75,000 (3)
81,000 (4)
90,000 (4)
100,000 (4)
113,000 (5)
125,000 (5)
Orifice Size (mm)
Orifice Diameter
2.45
0.0964
2.50
0.0984
2.60
0.1024
2.70
0.1063
2.75
0.1082
2.80
0.1102
2.90
0.1142
