Form I-UDA, P/N 195673 Rev 13, Page 15
High Altitude
Capacity Changes
5.
With the heater operating determine that the inlet pressure to the heater for natu
-
ral gas is between 5 and 13.5 inches w.c. and for propane between 10 and 13.5
inches w.c. Take this reading as close as possible to the heater (Heaters are
equipped with gas valves that have an inlet pressure tap.) If the inlet pressure is
not within the specified range, the inlet pressure must be corrected and Steps 3
and 4 repeated.
6.
Find the High Altitude Adjustment label in the plastic bag that contained these
instructions. Using a permanent marker, fill-in the appropriate information from the
tables below. Select a location for the label on the outside of the heater access
panel so that it will be conspicuous to anyone operating or servicing the unit. Be
sure the surface is clean and dry and adhere the label.
The input and/or the capacity of the heater changes with the derate. The tables below
list inputs and capacities at altitudes from sea level to 10,000 ft (3045M).
BTUH Inputs and Capacities by Altitude in the UNITED STATES for Model UDAP and Model UDAS
ALTITUDE
Normal
Input
Thermal Output
Capacity
Minimum
Input
Normal
Input
Thermal Output
Capacity
Minimum
Input
Normal
Input
Thermal Output
Capacity
Minimum
Input
Normal
Input
Thermal Output
Capacity
Minimum
Input
Feet
Meters
Size 30
Size 45
Size 60
Size 75
0-2000
0-610
30000
24600
30000 45000
37350
45000 60000
49800
42000 75000
62250
52500
2001-3000
611-915 28200
23124
28200
42300
35109
42300 56400
46812
39480
70500
58515
49350
3001-4000
916-1220
27600
22632
27600 41400
34362
41400 55200
45816
38640 69000
57270
48300
4001-5000 1221-1525 27000
22140
27000 40500
33615
40500 54000
44820
37800
67500
56025
47250
5001-6000
1526-1830
26400
21648
26400
39600
32868
39600 52800
43824
36960
66000
54780
46200
6001-7000
1831-2135 25800
21156
25800 38700
32121
38700
51600
42828
36120 64500
53535
45150
7001-8000
2136-2440 25200
20664
25200
37800
31374
37800
50400
41832
35280
63000
52290
44100
8001-9000
2441-2745 24600
20172
24600
36900
30627
36900 49200
40836
34440 61500
51045
43050
9001-10000
2746-3045 24000
19680
24000 36000
29880
36000
48000
39840
33600 60000
49800
42000
Feet
Meters
Size 100
Size 15
Size 150
Size 175
0-2000
0-610
105000
88200
73500 120000
100800
84000
150000
124500
105000 175000
145250
122500
2001-3000
611-915 98700
82908
69090 112800
94752
78960
141000
117030
98700
164500
136535
115150
3001-4000
916-1220 96600
81144
67620 110400
92736
77280 138000
114540
96600
161000
133630
112700
4001-5000 1221-1525
94500
79380
66150
108000
90720
75600 135000
112050
94500
157500
130725
110250
5001-6000
1526-1830 92400
77616
64680
105600
88704
73920
132000
109560
92400
154000
127820
107800
6001-7000
1831-2135 90300
75852
63210 103200
86688
72240
129000
107070
90300
150500
124915
105350
7001-8000
2136-2440
88200
74088
61740
100800
84672
70560 126000
104580
88200
147000
122010
102900
8001-9000
2441-2745
86100
72324
60270
98400
82656
68880
123000
102090
86100
143500
119105
100450
9001-10000
2746-3045
84000
70560
58800 96000
80640
67200 120000
99600
84000
140000
116200
98000
Feet
Meters
Size 00
Size 5
Size 50
Size 300
0-2000
0-610
200000
166000
140000 225000
186750
157500 250000
207500
175000 300000
249000
210000
2001-3000
611-915 188000
156040
131600 211500
175545
148050
235000
195050
164500
282000
234060
197400
3001-4000
916-1220 184000
152720
128800
207000
171810
144900
230000
190900
161000 276000
229080
193200
4001-5000 1221-1525
180000
149400
126000 202500
168075
141750 225000
186750
157500 270000
224100
189000
5001-6000
1526-1830
176000
146080
123200
198000
164340
138600
220000
182600
154000 264000
219120
184800
6001-7000
1831-2135
172000
142760
120400
193500
160605
135450 215000
178450
150500
258000
214140
180600
7001-8000
2136-2440
168000
139440
117600
189000
156870
132300 210000
174300
147000 252000
209160
176400
8001-9000
2441-2745 164000
136120
114800 184500
153135
129150
205000
170150
143500 246000
204180
172200
9001-10000
2746-3045 160000
132800
112000
180000
149400
126000 200000
166000
140000 240000
199200
168000
Feet
Meters
Size 350
Size 400
0-2000
0-610
350000
290500
245000 400000
332000
280000
2001-3000
611-915 329000
273070
230300 376000
312080
263200
3001-4000
916-1220
322000
267260
225400
368000
305440
257600
4001-5000 1221-1525 315000
261450
220500 360000
298800
252000
5001-6000
1526-1830 308000
255640
215600 352000
292160
246400
6001-7000
1831-2135
301000
249830
210700 344000
285520
240800
7001-8000
2136-2440
294000
244020
205800
336000
278880
235200
8001-9000
2441-2745
287000
238210
200900 328000
272240
229600
9001-10000
2746-3045
280000
232400
196000
320000
265600
224000
BTUH Inputs and Capacities by Altitude in CANADA for Models UDAP and UDAS
ALTITUDE
Normal
Input
Thermal Output
Capacity
Minimum
Input
Normal
Input
Thermal Output
Capacity
Minimum
Input
Normal
Input
Thermal Output
Capacity
Minimum
Input
Normal
Input
Thermal Output
Capacity
Minimum
Input
Feet
Meters
Size 30
Size 45
Size 60
Size 75
0-2000
0-610
30000
24600
30000 45000
37350
45000 60000
49800
42000 75000
62250
52500
2001-4500 611-1373 27000
22140
27000 40500
33615
40500 54000
44820
37800
67500
56025
47250
Feet
Meters
Size 100
Size 15
Size 150
Size 175
0-2000
0-610
105000
88200
73500 120000
100800
84000
150000
124500
105000 175000
145250
122500
2001-4500 611-1373
94500
79380
66150
108000
90720
75600 135000
113400
94500
157500
132300
110250
Feet
Meters
Size 00
Size 5
Size 50
Size 300
0-2000
0-610
200000
166000
140000 225000
186750
157500 250000
207500
175000 300000
249000
210000
2001-4500 611-1373
180000
151200
126000 202500
170100
141750 225000
189000
157500 270000
226800
189000
Feet
Meters
Size 350
Size 400
0-2000
0-610
350000
290500
245000 400000
332000
280000
2001-4500 611-1373 315000
264600
220500 360000
302400
252000