Rheem 95MSP series, Installation Instructions Manual

Page: 85 / 100

85
HIGH ALTITUDE
LP GAS AT HIGH ALTITUDES
ORIFICE INSTALLATION
LP Gas is a manufactured gas that has consistent heating
value across most regions.
The NFGC guidelines are used with the following excep-
tion:
The recommended LP Gas high altitude orifice selections
differ slightly in that the NFGC LP orifice chart, as they are
not accurate for this furnace product. The National Fuel
Gas Code LP orifices are based on an 11
of water column
pressure at the orifice, which differs from this furnace prod-
uct that use 10
of water column at the orifice. This differ-
ence requires a deviation from the NFGC orifice size
recommendations. The Sea Level input should still be re-
duced by 4% per thousand ft. and the orifice size must be
selected based on the reduced input selection Table 15.
ORIFICE ORDERING INFORMATION
Orifice sizes are selected by adding the 2-digit drill size re-
quired in the orifice part number. Drill sizes available are
39 through 64; metric sizes available 1.10mm (-90):
Orifice Part Number 62-22175-(drill size)
Example 1:
# 60 drill size orifice required
Part # 62-22175-60
Example 2:
1.10 mm drill size orifice required
Part # 62-22175-90
ALTERNATE METHOD OF
CANADIAN HIGH-ALTITUDE
DERATE
In Canada, unless an orifice change is specifically man-
dated by local codes, an alternate method of altitude dera-
tion through a reduction in manifold pressure is acceptable
as described in Table 16.
The information in Table 16 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 on-site
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 46 must be affixed in a conspicuous loca-
tion on the front of the furnace cabinet:
NOTE: This label is supplied in the information packet
shipped with each furnace.
TABLE 15
LP GAS ORIFICE DRILL SIZE
(4% PER 1000 FT DE-RATE)
IMPORTANT:
90 Plus Models only.
Input (per
Altitude burner) 14000 Orifice Size
0 to 2000 ft. 14,000 1.10 mm
(factory kit)
2000 -3000 12,320 #58
3000 -4000 11,760 #59
4000 -5000 11,200 #59
5000 -6000 10,640 #60
6000 -7000 10,080 #60
7000 -8000 9,520 #61
8000 -9000 8,960 #62
9000 -10000 8400 #63
TABLE 16
ALTERNATE METHOD FOR CANADIAN HIGH-ALTITUDE DERATE
IMPORTANT:
90 Plus Models only.
NATURAL GAS LP GAS
ALTITUDE INPUT OUTPUT
ORIFICE
SIZE
MANIFOLD
PRESSURE
0’ - 2000’
42,000
56,000
70,000
84,000
98,000
112,000
39,900
53,200
66,500
79,800
93,100
106,400
#51 3.5” W.C.
2001’ - 4500’
37,800
50,400
63,000
75,600
88,200
100,800
35,910
47,880
59,850
71,820
83,790
95,760
#51 3.0” W.C.
ALTITUDE INPUT OUTPUT
ORIFICE
SIZE
MANIFOLD
PRESSURE
0’ - 2000’
42,000
56,000
70,000
84,000
98,000
112,000
39,900
53,200
66,500
79,800
93,100
106,400
1.15mm 10” W.C.
2001’ - 4500’
37,800
50,400
63,000
75,600
88,200
100,800
35,910
47,880
59,850
71,820
83,790
95,760
1.15mm 7.6” W.C.
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.
FIGURE 46
MANIFOLD PRESSURE-CHANGE LABEL
92-24399-01-01
High Altitude