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18
Appendix B
DE-RATING FOR HIGH ALTITUDE
For U.S. installations, the Clarity B-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 B-Vent is ap
-
proved for elevations up to 610 meters (2000 feet). For
installations from 610-1370 meters (2000-4500 ft.) the
orice sizes (DMS) for natural and propane gas are as
shown in the chart below.
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 3-40-64347 56 3-40-57356 39 3-40-64739 40,000
2000-3000' 48 MALE 56 3-40-57356 40 MALE 38,400
3000-4000' 49 MALE 56 3-40-57356 41 MALE 36,900
4000-5000' 49 MALE 57 MALE 42 MALE 35,400
5000-6000' 50 MALE 57 MALE 42 MALE 34,000
6000-7000' 50 MALE 57 MALE 43 MALE 32,600
7000-8000' 51 MALE 58 MALE 43 MALE 31,300
8000-9000' 51 MALE 58 MALE 44 MALE 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 3-40-57356 71 3-40-57271 53 3-40-57753 40,000
2000-3000' 56 3-40-57356 71 3-40-57271 54 MALE 36,900
3000-4000' 56 3-40-57356 71 3-40-57271 54 MALE 36,900
4000-5000' 57 MALE 71 3-40-57271 54 MALE 35,400
5000-6000' 57 MALE 71 3-40-57271 55 MALE 32,600
6000-7000' 57 MALE 71 3-40-57271 55 MALE 32,600
7000-8000' 58 MALE 71 3-40-57271 56 3-40-57356 30,100
8000-9000' 58 MALE 71 3-40-57271 56 3-40-57356 30,100
For high altitude installations consult the local gas dis
-
tributor 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 below must be
lled out and afxed to the appliance at the time of conver-
sion.
THE CONVERSION SHALL BE CARRIED OUT
BY A MANUFACTURER'S AUTHORIZED REP
-
RESENTATIVE IN ACCORDANCE WITH THE
REQUIREMENTS OF THE MANUFACTURER,
PROVINCIAL OR TERRITORIAL AUTHORITIES
HAVING JURISDICTION AND IN ACCORDANCE
WITH THE REQUIREMENTS OF THE CURRENT
EDITION OF CAN/CGA-B141.1 OR CAN/CGA-
B141.2 INSTALLATION CODES.
This appliance has been converted for use at an altitude of __________ft.
Orice Sizes: Front ________ Center_________ Rear ________
Input (Btu/hr) _________________
Manifold Pressure __________________
Fuel Type _______________________
Converted By _________________________________
Date of Conversion _______________________________
●When ordering injectors that have no Harman
Part number, specify MALE or FEMALE and
the appropriate 2- digit number.