21
De-rating for High Altitude
For U.S. installations, the Clarity Direct Vent is approved for elevations up to 2000 feet using the factory-installed burner
injectors. At elevations above 2000 feet, U.S. codes require a decrease in the input rating by changing the burner injectors to
a smaller size. The chart below lists by part numbers the appropriate injectors for both LP and natural gas at various altitudes.
For Canadian installations, the Clarity Direct Vent is approved for elevations up to 1375 meters (4500 feet). When installing
the Clarity Direct Vent at altitudes above 1375 meters (4500 feet), consult the local gas distributor or the authority having
jurisdiction for proper rating methods.
NOTE: The difference in altitude derating requirements for the U.S. and Canada is simply a result of differences in testing
standards between the two countries.
If the installer must convert the unit to adjust for varying altitudes, an information sticker like the one to the right must be
filled out and affixed to the appliance at the time of conversion.
NATURAL GAS
Front
Harman
Center
Harman
Rear
Harman
Nominal Btu
Altitude
Injector Part No.
Injector Part No.
Injector Part No.
Input Rate
0-2000'
47
Standard
56
Standard
39
Standard
40,000
2000-3000'
48
3-40-25848
56
Standard
40
3-40-25840
38,400
3000-4000'
49
3-40-25849
56
Standard
41
3-40-25841
36,900
4000-5000'
49
3-40-25849
57
3-40-25857
42
3-40-25842
35,400
5000-6000'
50
3-40-25850
57
3-40-25857
42
3-40-25842
34,000
6000-7000'
50
3-40-25850
57
3-40-25857
43
3-40-25843
32,600
7000-8000'
51
3-40-25851
58
3-40-25858
43
3-40-25843
31,300
8000-9000'
51
3-40-25851
58
3-40-25858
44
3-40-25844
30,100
PROPANE
Front
Harman
Center
Harman
Rear
Harman
Nominal Btu
Altitude
Injector Part No.
Injector Part No.
Injector Part No.
Input Rate
0-2000'
56
Standard
71
Standard
53
Standard
40,000
2000-3000'
56
Standard
71
Standard
54
3-40-25854
36,900
3000-4000'
56
Standard
71
Standard
54
3-40-25854
36,900
4000-5000'
57
3-40-25857
71
Standard
54
3-40-25854
35,400
5000-6000'
57
3-40-25857
71
Standard
55
3-40-25855
32,600
6000-7000'
57
3-40-25857
71
Standard
55
3-40-25855
32,600
7000-8000'
58
3-40-25858
71
Standard
56
3-40-25856
30,100
8000-9000'
58
3-40-25858
71
Standard
56
3-40-25856
30,100
THE CONVERSION SHALL BE CARRIED OUT
BY A MANUFACTURER'S AUTHORIZED REPRE-
SENTATIVE IN ACCORDANCE WITH THE RE-
QUIREMENTS OF THE MANUFACTURER, PRO-
VINCIAL OR TERRITORIAL AUTHORITIES HAV-
IN G J URISDICTION AND IN AC COR DAN CE
WITH THE REQUIREMENTS OF THE CURRENT
EDITION OF CAN/CGA-B141.1 OR CAN/CGA-
B141.2 INSTALLATION CODES.
APPENDIX B
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