Installation Instructions
Page 29
Pub. No. 41-5016-12
HIGH ALTITUDE DERATE
Input ratings (BTUH) of these furnaces are based on sea level
operation and should not be changed at elevations up to 2,000 ft.
If the installation is 2,000 ft. or above, the furnace input rate
(BTUH) shall be reduced 4% for each 1,000 ft. above sea level. The
furnace input rate shall be checked by clocking the gas flow rate
(CFH) and multiplying by the heating value obtained from the
local utility supplier for the gas being delivered at the installed
altitude.
Input rate changes can be made by adjusting the manifold pres-
sure (min 3.0 - max 3.7 in. W.C. - Natural Gas) or changing orifices
(orifice change may not always be required). If the desired input
rate cannot be achieved with a change in manifold pressure, then
the orifices must be changed.
LP installations will require an orifice change. See Table 13 for
help in selecting orifices if orifice change is required.
IMPORTANT:
Reinstall the propane orifices to the same depth as the orifices
supplied with the equipment.
TABLE 10
GAS FLOW IN CUBIC FEET PER HOUR
2 CUBIC FOOT DIAL
SEC. FLOW
SEC. FLOW
SEC. FLOW
SEC. FLOW
8
900
29
248
50
144
82
88
9
800
30
240
51
141
84
86
10
720
31
232
52
138
86
84
11
655
32
225
53
136
88
82
12
600
33
218
54
133
90
80
13
555
34
212
55
131
92
78
14
514
35
206
56
129
94
76
15
480
36
200
57
126
96
75
16
450
37
195
58
124
98
73
17
424
38
189
59
122
100
72
18
400
39
185
60
120
104
69
19
379
40
180
62
116
108
67
20
360
41
176
64
112
112
64
21
343
42
172
66
109
116
62
22
327
43
167
68
106
120
60
23
313
44
164
70
103
124
58
24
300
45
160
72
100
128
56
25
288
46
157
74
97
132
54
26
277
47
153
76
95
136
53
27
267
48
150
78
92
140
51
28
257
49
147
80
90
144
50
TABLE 12
PART NUMBERS FOR REPLACEMENT ORIFICES
DRILL
SIZE
PART
NUMBER
DRILL
SIZE
PART
NUMBER
44
45
46
47
48
49
50
ORF00501
ORF00644
ORF00909
ORF00910
ORF01099
ORF00503
ORF00493
54
55
56
57
58
59
ORF00555
ORF00693
ORF00907
ORF00908
ORF01338
ORF01339
TABLE 13
Orifice
Twist Drill
Size If
Installed
At Sea
Level
ALTITUDE ABOVE SEA LEVEL
and Orifice Required At Other Elevations
2000 3000 4000 5000 6000 7000 8000 9000 10000
42
43
44
45
46
47
42
44
45
46
47
48
43
44
45
47
47
48
43
44
45
47
47
49
43
45
46
47
48
49
44
45
47
48
48
49
44
46
47
48
49
50
45
47
48
49
49
50
46
47
48
49
50
51
47
48
50
50
51
52
54
55
56
57
58
54
55
56
58
59
55
55
56
59
60
55
55
57
59
60
55
56
57
60
61
55
56
57
60
62
55
56
58
61
62
56
56
59
62
63
56
56
59
63
63
56
57
60
63
64
From National Fuel Gas Code - Table F-4
TABLE 11
FINAL MANIFOLD PRESSURE SETTINGS
FUEL
PRESSURE
NATURAL GAS
3.5" W.C.
LP GAS
11.0" W.C.
Installation of this furnace at altitudes above 2,000 ft.
(610m) shall be in accordance with the 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, CSA 149.1
. Installation
of this furnace at altitudes above 2,000 ft. (610m) shall be
made in accordance with the listed high Altitude Conver-
sion Kit available with this furnace.
9. Using a leak detection solution or soap suds, check for leaks
at the pressure outlet boss and pressure tap test screw.
10. Turn on system power and check operation of the unit.
▲
WARNING
!
Replace and/ or tighten all plugs removed or loosened
when adjusting gas pressure. Leak check the fittings be-
fore placing the Furnace into regular service.
Failure to follow this warning could result in fire, explo-
sion, property damage, or death.
Table 9 – page 24, lists the main burner orifices used with the
furnace. If a change of orifices is required to correct the furnace
input rating refer to Table 12.
Furnace input rate and temperature rise should be checked again
after changing orifices to confirm the proper rate for the altitude.
Installations above 4,000 feet may require a pressure switch
change. If required, use the BAYHALT*** Kit (High Altitude
Accessory Kit) listed in PRODUCT DATA.
