CaptiveAire DOAS RTU Series, Installation, Operation And Maintenance Manual

Page: 19 / 136

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High Altitude and Gas Type Orifice Sizing
The burner orifices should be sized per Table 6 and Table 7 , depending on fuel type, furnace size, and
altitude. Standard orifice sizes are for sea level. The unit should be ordered with the altitude specific
orifices, or the parts should be ordered through the manufacturer ( Table 8 on page 20 ). Refer to main gas
valve documentation for instructions to convert gas valve spring from Natural to LP and vice versa.
NOTE: 50,000 – 100,000 BTU High-Efficiency Natural Gas furnaces use 2.3mm Drill Size at 0 – 3999
ft. Follow charts for all other altitudes.
Table 6 - Natural Gas High Altitude Charts
Natural Gas High Altitude Conversion
Size 3 Size 2 and 3 Size 1, 2, and 3
High Altitude for 500,000
BTU
High Altitude for 400,000
BTU
High Altitude for 300,000 to 50,000
BTU
Altitude
(Feet)
Input Rate Drill Size Input Rate Drill Size Input Rate Input Rate Input Rate Drill Size
0 - 1,999 500,000 #33 400,000 #41 300,000 200,000 150,000 #3/32
2,000 - 2,999 479,998 #35 384,000 #42 288,000 192,000 144,000 2.35mm
3,000 - 3,999 460,797 #35 368,640 2.35mm 276,480 184,320 138,240 2.3mm
4,000 - 4,999 442,668 #36 353,894 2.3mm 265,421 176,947 132,710 #43
5,000 - 5,999 424,668 #36 339,739 #43 254,804 169,869 127,402 2.25mm
6,000 - 6,999 407,680 #37 326,149 2.25mm 244,612 163,075 122,306 #44
7,000 - 7,999 391,372 #38 313,103 #44 234,827 156,552 117,414 2.15mm
8,000 - 8,999 375,716 #38 300,579 #45 225,434 150,290 112,717 #46
9,000 - 10,000 360,686 #40 288,556 #46 216,417 144,278 108,209 #47
Natural Gas High Altitude Conversion
Size 4 Size 4
High Altitude for 600,000 BTU High Altitude for 500,000 to 200,000 BTU
Altitude
(Feet)
Input Rate Drill Size Input Rate Input Rate Input Rate Input Rate Drill Size
0 - 1,999 600,000 3.4mm 500,000 400,000 300,000 200,000 3.3mm
2,000 - 2,999 576,000 #30 479,998 384,000 288,000 192,000 #30
3,000 - 3,999 552,960 #30 460,797 368,640 276,480 184,320 #31
4,000 - 4,999 530,482 #30 442,668 353,894 265,421 176,947 #31
5,000 - 5,999 509,608 #30 424,668 339,739 254,804 169,869 #31
6,000 - 6,999 489,224 #30 407,680 326,149 244,612 163,075 #31
7,000 - 7,999 469,654 #31 391,372 313,103 234,827 156,552 #32
8,000 - 8,999 450,868 #31 375,716 300,579 225,434 150,290 #32
9,000 - 10,000 432,834 #32 360,686 288,556 216,417 144,278 #33