23
LP GAS AT HIGH ALTITUDE
ELEVATION (TABLE 6)
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 Rheem 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 6.
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 1:
#60 drill size orifice required
Part # 62-22175-60
Example 2:
1.15mm drill size orifice required
Part #62-22175-91
ALTERNATE METHOD FOR
CANADIAN
HIGH-ALTITUDE
DERATE
In Canada, unless an orifice change is
specifically mandated by local codes, an
alternate method of altitude deration
through a reduction in manifold
pressure is acceptable as described in
Table 7. This information is based on a
heating value of 1000 BTU per cubic
feet of natural gas, and 2500 BTU per
cubic feet of LP gas.
IMPORTANT: Actual input rates must
be measured onsite with manifold
pressure adjustment to ensure that an
actual 10% reduction in input rate is
achieved.
Once this field adjustment has been
made, the label shown in Figure 19
must be affixed in a conspicuous
location on the front of the furnace
cabinet.
NOTE: This label is supplied in the
information packet shipped with each
furnace.
FURNACE INSTALLATION
WITH HIGH-EFFICIENCY
PREMIUM COOLING
SYSTEMS
Furnace installation with Rheem/Ruud
-ARA or -ARL outdoor condensing
units can provide high efficiency (up to
16 SEER) cooling operation. Using
Tables 9 and 10, and literature
provided with the cooling equipment,
the installer needs to make sure that
the proper evaporator coil, condensing
coil and airflow is configured to achieve
rated efficiency.
TABLE 7
ALTERNATE METHOD FOR CANADIAN HIGH-ALTITUDE DERATE
IMPORTANT: 80+ MODELS ONLY. DO NOT
USE THIS CHART FOR ANY 90+ MODELS.
HIGH FIRE NATURAL GAS HIGH FIRE LP GAS
ALTITUDE
INPUT
OUTPUT
ORIFICE
SIZE
MANIFOLD
PRESSURE
0’ - 2000’
#42
3.5” W.C.
2001’ - 4500’
#42
2.9” W.C.
ALTITUDE
INPUT
OUTPUT
ORIFICE
SIZE
MANIFOLD
PRESSURE
0’ - 2000’
#54
10” W.C.
2001’ - 4500’
#54
8.1” W.C.
50,000 40,000
75,000 60,000
100,000 80,000
125,000 100,000
150,000 120,000
45,000 36,000
67,500 54,000
90,000 72,000
112,500 90,000
135,000 108,000
50,000 40,000
75,000 60,000
100,000 80,000
125,000 100,000
150,000 120,000
45,000 36,000
67,500 54,000
90,000 72,000
112,500 90,000
135,000 108,000
ALTITUDE
INPUT
OUTPUT
ORIFICE
SIZE
MANIFOLD
PRESSURE
0’ - 2000’
#42
1.7” W.C.
2001’ - 4500’
#42
1.4” W.C.
ALTITUDE
INPUT
OUTPUT
ORIFICE
SIZE
MANIFOLD
PRESSURE
0’ - 2000’
#54
4.9” W.C.
2001’ - 4500’
#54
4.0” W.C.
35,000 28,000
52,500 42,000
70,000 56,000
87,500 70,000
105,000 84,000
31,500 25,200
47,250 37,800
63,000 50,400
78,750 63,000
94,500 75,600
35,000 28,000
52,500 42,000
70,000 56,000
87,500 70,000
105,000 84,000
31,500 25,200
47,250 37,800
63,000 50,400
78,750 63,000
94,500 75,600
LOW FIRE NATURAL GAS LOW FIRE LP GAS
FIGURE 19
MANIFOLD PRESSURE-CHANGE LABEL
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