Gas Piping - Lennox EL280UH070P24A Installation Instructions Manual

Gas Piping

Gas supply piping should not allow more than 0.5"W.C.
drop in pressure between gas meter and unit. Supply gas
pipe must not be smaller than unit gas connection
CAUTION
If a flexible gas connector is required or allowed by the
authority that has jurisdiction, black iron pipe shall be
installed at the gas valve and extend outside the furnace
cabinet. The flexible connector can then be added
between the black iron pipe and the gas supply line.
Gas Supply
WARNING
Do not over torque (800 in-lbs) or under torque (350 in-
lbs) when attaching the gas piping to the gas valve.
1 - This unit is shipped standard for left or right side
installation of gas piping (or top entry in horizontal
applications). Connect the gas supply piping into
the gas valve. The maximum torque is 800 in lbs
and minimum torque is 350 in lbs when attaching
the gas piping to the gas valve.
Nominal Internal
Iron Pipe Diameter
Size Inches inches
(mm) (mm)
1/2 .622
(12.7) (17.799)
3/4 .824
(19.05) (20.930)
1 1.049
(25.4) (26.645)
1-1/4 1.380
(31.75) (35.052)
1-1/2 1.610
(38.1) (40.894)
2 2.067
(50.8) (52.502)
2-1/2 2.469
(63.5) (67.713)
3 3.068
(76.2) (77.927)
NOTE - Capacity given in cubic feet (m3 ) of gas per hour and based on 0.60 specific gravity gas.
Gas Pipe Capacity - ft3/hr (m3/hr)
10 20 30
(3.048) (6.096) (9,144)
172 118 95
(4.87) (3.34) (2.69)
360 247 199
(10.19) (7.000) (5.63)
678 466 374
(19.19) (13.19) (10.59)
1350 957 768
(38.22) (27.09) (22.25)
2090 1430 1150
(59.18) (40.49) (32.56)
4020 2760 2220
(113.83) (78.15) (62.86)
6400 4400 3530
(181.22) (124.59) (99.95)
11300 7780 6250
(319.98) (220.30) (176.98)
2 - When connecting the gas supply piping, consider
factors such as length of run, number of fittings, and
furnace rating to avoid excessive pressure drop.
Table 6 lists recommended pipe sizes for typical
applications.
3 - The gas piping must not run in or through air ducts,
clothes chutes, gas vents or chimneys, dumb
waiters, or elevator shafts.
4 - The piping should be sloped 1/4 inch (6.4 mm) per
15 feet (4.57 m) upward toward the meter from the
furnace. The piping must be supported at proper
intervals [every 8 to 10 feet (2.44 to 3.01 m)] with
suitable hangers or straps. Install a drip leg in
vertical pipe runs to the unit.
5 - A 1/8" N.P.T. plugged tap or pressure post is located
on the gas valve to facilitate test gauge connection.
See figure 31.
6 - In some localities, codes may require the installation
of a manual main shut-off valve and union (furnished
by the installer) external to the unit. The union must
be of the ground joint type.
Compounds used on threaded joints of gas piping must
be resistant to the actions of liquified petroleum gases.
NOTE - If emergency shutoff is necessary, shut off the
main manual gas valve and disconnect main power to the
furnace. The installer should properly label these devices.
TABLE 6
Length of Pipe - feet (m)
40 50 60
(12,192) (15.240) (18.288)
81 72 65
(2.29) (2.03) (1.84)
170 151 137
(4.81) (4.23) (3.87)
320 284 257
(9.06) (8.04) (7.27)
657 583 528
(18.60) (16.50) (14.95)
985 873 791
(27.89) (24.72) (22.39)
1900 1680 1520
(53.80) (47.57) (43.04)
3020 2680 2480
(85.51) (75.88) (70.22)
5350 4740 4290
(151.49) (134.22) (121.47)
Page 21
IMPORTANT
70 80 90
(21.336) (24.384) (27.432)
60 56 52
(1.69) (1.58) (1.47)
126 117 110
(3.56) (3.31) (3.11)
237 220 207
(6.71) (6.23) (5.86)
486 452 424
(13.76) (12.79) (12.00)
728 677 635
(20.61) (19.17) (17.98)
1400 1300 1220
(39.64) (36.81) (34.55)
2230 2080 1950
(63.14) (58.89) (55.22)
3950 3670 3450
(111.85) (103.92) (97.69)
100
(30,480)
50
(1.42)
104
(2.94)
195
(5.52)
400
(11.33)
600
(17.00)
1160
(32.844)
1840
(52.10)
3260
(92.31)