Operation
GUNE-SVX001A-EN
29
Tubular Duct Furnace—High Altitude
Deration
This tubular duct furnace has been manufactured utilizing
standard burner orifices and a normal manifold pressure
setting as per the specifications shown on your unit rating
plate.
All unit deration must be done through field adjustments
by a qualified technician. Once the proper adjustments are
made in the field, attach label #J17-06459 to the unit, and
record adjusted manifold pressure, altitude of the unit
installation, the technician’s name, and the date on the
label using a permanent marker.
Refer to
“Adjusting Gas Pressure,” p. 28
for adjusting the
manifold pressure.
Table 10.
High altitude deration—United States
Altitude
Manifold Pressure
BTU Output
(a)
Natural Gas
(b)
Liquid Propane
(c)
Feet
Meters
Inches wc
Pa
Inches wc
Pa
Percentage
0–2,000
0–610
3.5
872
10.0
2491
100%
2,001–3,000
611–915
3.2
797
9.2
2292
96%
3,001–4,000
916–1,220
2.9
722
8.4
2092
92%
4,001–5,000
1,221–1,525
2.7
673
7.7
1918
88%
5,001–6,000
1,526–1,830
2.4
598
7.0
1744
84%
6,001–7,000
1,831–2,135
2.2
548
6.4
1594
80%
7,001–8,000
2,136–2,440
2.0
498
5.7
1420
76%
8,001–9,000
2,441–2,745
1.8
448
5.1
1270
72%
9,001–10,000
2,746–3,045
1.6
399
4.6
1145
68%
Note:
Consult local utility for actual heating value.
(a) Deration based on ANSI Z223.1 (NFPA 54).
(b) Table based on heating value of 1,050 Btu/ft
3
at sea level.
(c) Table based on heating value of 2,500 Btu/ft
3
feet at sea level.
Table 11.
High altitude deration —Canada
Altitude
Manifold Pressure
BTU Output
(a)
Natural Gas
(b)
Liquid Propane
(c)
Feet
Meters
Inches wc
Pa
Inches wc
Pa
Percentage
0–2,000
0–610
3.5
872
10.0
2491
100%
2,001–3,000
611–915
3.2
797
9.2
2292
96%
3,001–4,000
916–1,220
2.9
722
8.4
2092
92%
4,001–5,000
1,221–1,371
2.8
697
7.9
1968
90%
Note:
Consult local utility for actual heating value.
(a) Deration based on CGA 2.17-M91.
(b) Table based on heating value of 1,050 Btu/ft
3
feet at sea level.
(c) Table based on heating value of 2,500 Btu/ft
3
at sea level.
