27
80+ HIGH ALTITUDE
INSTRUCTIONS
(TABLES 6 & 9)
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 NATIONAL
FUEL GAS CODE, ANSI Z223.1/NFPA
54 OR NATIONAL STANDARD OF
CANADA, NATURAL GAS AND
PROPANE INSTALLATION CODE,
CAN B149.1.
34" 80 Plus furnaces installed above
2,000 ft. require the furnace to be de-
rated 4% per thousand feet.
IMPORTANT:
Factory installed orifices
are calculated and sized based on a sea
level Natural Gas heating value of 1075
BTU per cubic ft.
NOTE:
Orifices are available through
your local distributor.
Reference Tables 6 and 9 for
appropriate orifice sizing.
The following are examples of orifice
sizing using the National Fuel Gas Code
Appendix F:
For a simplified estimation of orifice size
based on gas heating value and
elevation, Tables 6 and 9 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 F.1 of
National Fuel Gas
Code Handbook, 2002
(3.5
ⴖ
w.c.
column).
Orifice required at Sea Level: #40
From Table F.4 of
National Fuel Gas
Code Handbook, 2002
Orifice required 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 F.1 of
Natural Fuel Gas
Code Handbook, 2002
(3.5
⬙
w.c.
column).
Orifice required at Sea Level: #43
From Table F.4 of
National Fuel Gas
Code Handbook, 2002
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
LP GAS (TABLE 7)
NOTE:
Keep any parts removed during
LP conversion procedure stored with
the product literature for future use.
LP Gas is a manufactured gas that has
consistent heating value across most
regions.
The NFGC guidelines are used with the
following exception:
The recommended LP Gas high
altitude orifice selections differ slightly
in that the NFGC LP orifice chart, as
they are not accurate for Rheem
products. The National Fuel Gas Code
LP orifices are based on an 11" of
water column pressure at the orifice,
which differs from products that use 10"
of water column at the orifice. This
difference requires a deviation from the
NFGC orifice size recommendations.
The Sea Level input should still be
reduced by 4% per thousand ft. and the
orifice size must be selected based on
the reduced input in Table 7.
FIGURE 19
MANIFOLD PRESSURE-CHANGE LABEL
THE MANIFOLD PRESSURE OF THIS APPLIANCE HAS
BEEN FIELD ADJUSTED TO OBTAIN THE CORRECT
INPUT RATING FOR INSTALLATION AT ALTITUDES
BETWEEN 2,000 FEET AND 4,500 FEET ELEVATION.
LA PRESSION DU DISTRIBUTEUR D'ALIMENTATION
DE CET APPAREIL A ÉTÉ AJUSTÉ SUR LES LIEUX AFIN
D'OBTENIR LA BONNE PUISSANCE D'ENTRÉE POUR
UNE INSTALLATION ENTRE 2000 ET 4500 PIEDS
D'ALTITUDE.
92-24399-01-01
!
CAUTION
Natural Gas Orifice Drill Size (4% per 1000 ft. De-Rate)
IMPORTANT:
80+ Models only. Do not use this chart for any 90+ Models.
Burner Input (per burner) 25,000 BTU @ Sea Level
Sea level
2000 to
3000 to
4000 to
5000 to
6000 to
7000 to
8000 to
to 1999 ft
2999 ft
3999 ft
4999 ft
5999 ft
5999 ft
7999 ft
8999 ft
38
39
40
41
41
42
42
43
40
41
42
42
42
43
43
44
41
42
42
42
43
43
44
44
42
42
43
43
43
44
44
45
43
44
44
44
45
45
46
47
Annual Avg. Heat
Value (btu per ft
3
)
850
900
975
1075
1170
TABLE 6
TABLE 7
LP GAS
IMPORTANT: 80+ MODELS ONLY! DO NOT
USE THIS CHART WITH ANY 90+ MODELS.
Input (per
Orifice
Altitude
burner) 25000
Size
0 to 2000 ft.
25000
#54
2000
ⴕ
-3000
ⴕ
24000
#54
3000
ⴕ
-4000
ⴕ
23000
#54
4000
ⴕ
-5000
ⴕ
22000
#54
5000
ⴕ
-6000
ⴕ
21000
#54
6000
ⴕ
-7000
ⴕ
20000
#54
7000
ⴕ
-8000
ⴕ
19000
#55
8000
ⴕ
-9000
ⴕ
18000
#55
9000
ⴕ
-10000
ⴕ
17000
#55
Содержание GMDA
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