Rheem 801C Series User Manual

35
High Altitude
HIGH ALTITUDE
34” 80 Plus furnaces installed above 2,000 ft. require the furnace
to be de-rated 4% per thousand feet above sea level.
IMPORTANT: Factory installed orifices are calculated and sized
based on a sea level Natural Gas heating value of 1050 BTU per
cubic ft.
NOTE: Orifices are available through your local distributor.
Reference Table 8 for approximate orifice sizing.
The following are examples of orifice sizing using the National
Fuel Gas Code Appendix E, 2015 edition.
For a simplified estimation of orifice size based on gas heating
value and elevation, Table 8 may be used. However, calculations
are the best method.
Example: 900 BTU/ft
3
Regional Natural Gas Heating Value
I/H = Q
25000 / 900 = 27.78 ft
3
I = Sea Level input (per burner): 25000
H = Sea Level Heating Value: 900
Q = 27.78 ft
3
Natural Gas per hour.
From Table E1.1a of National Fuel Gas Code, 2015 (3.5( w.c.
column).
Orifice required at Sea Level: #40
From Table E1.1d of National Fuel Gas Code, 2015. Orifice re-
quired at 5000 ft. elevation (4% de-rate per thousand ft): #42
Orifice required at 8000 ft. elevation (4% de-rate per thousand
ft.): #44
Example: 1050 BTU/ft3 Regional Natural Gas Heating Value
I / H = Q
25000 / 1050 = 23.81ft
3
I = Sea Level input (per burner): 25000
H = Sea Level Heating Value: 1050
Q = 23.81 ft
3
Natural Gas per hour.
From Table E1.1a of National Fuel Gas Code, 2015 (3.59 w.c.
column).
Orifice required at Sea Level: #43
From Table E1.1d of National Fuel Gas Code, 2015
Orifice required at 5000 ft. elevation (4% de-rate per
thousand ft.): #45
Orifice required at 8000 ft elevation (4% de-rate per
thousand ft): #47
ORIFICE ORDERING INFORMATION
Orifice sizes are selected by adding the 2-digit drill size required
in the orifice part number. Drill sizes available are 39 through 64;
metric sizes available 1.10mm (-90) and 1.15mm (-91):
Orifice Part Number 62-22175-(drill size)
Example:
# 60 drill size orifice required
Part # 62-22175-60
NATURAL GAS AT HIGH ALTITUDES
!
WARNING
INSTALLATION OF THIS FURNACE AT ALTITUDES ABOVE
2000 FT (610 m) SHALL BE IN ACCORDANCE WITH LOCAL
CODES, OR IN THE ABSENCE OF LOCAL CODES, THE NA-
TIONAL FUEL GAS CODE, ANSI Z223.1/NFPA 54.
!
CAUTION
ELEVATIONS ABOVE 2000 FT. REQUIRE THAT THE FUR-
NACE INPUT RATING BE ADJUSTED AND THAT THE
SIZE OF THE BURNER ORIFICES BE RE-CALCULATED
BASED ON ELEVATION AND GAS HEATING VALUE. THE
BURNER ORIFICES MAY (OR MAY NOT) NEED TO BE
CHANGED. THE FOLLOWING EXAMPLES SHOW HOW
TO DETERMINE IF AN ORIFICE CHANGE WILL BE NEC-
ESSARY AND HOW TO DETERMINE THE NEW ORIFICE
SIZE.

Rheem 801C Series Specifications

General

Brand	Rheem
Model	801C Series
Category	Furnace
Language	English