INSTALLATION
Horizontal Two Pipe Venting
1. When horizontal vents pass through a combustible wall (up
to 8 inches thick), the vent passage must be constructed
and insulated as shown in Figure 10.
2. The termination of horizontally vented system must extend
12 inches beyond the exterior surface of an exterior wall.
3. The combustion air pipe must be a minimum of 16 inches
below the vent pipe, and 24 inches from the exterior wall.
4. Support the vent and combustion air pipe as shown in
Figure 10.
P
iping
1. Installation of piping must be in accordance with local
codes, and ANSI Z223.1, “National Fuel Gas Code,” or
CAN/CGA-B149 in Canada.
2. Piping to units should conform with local and national
requirements for type and volume and gas handled, and
pressure drop allowed in the line. Refer to Table 5, to
determine the cubic feet per hour (cfh) for the type of gas
and size of unit to be installed. Using this cfh value and the
length of pipe necessary, determine the pipe diameter from
Table 2. Where several units are served by the same main,
the total capacity, cfh, and length of main must be
considered. Avoid pipe sizes smaller than 1/2".Table 2
allows for the usual number of fittings with a 0.3; W.C.
pressure drop. Where the gas supplied has a specific
gravity other than 0.60, apply the multiplying factor as given
in Table 3.
3. After threading and reaming the ends, inspect piping and
remove loose dirt and chips.
4. Support piping so that no strains are imposed on unit or
controls.
5. Use two wrenches when connecting piping to unit controls.
Length Diameter of Pipe — Inches
of Pipe
in Ft. 1/2 3/4 1 1-1/4 1-1/2
15 76 218 440 750 1220
30 73 152 285 590 890
45 44 124 260 435 700
60 50 105 190 400 610
75 97 200 345 545
90 88 160 320 490
105 80 168 285 450
120 158 270 420
150 120 242 380
180 128 225 350
210 205 320
240 190 300
270 178 285
300 170 270
450 140 226
600 119 192
L
ength Diameter of Pipe — Inches
of Pipe
in Ft. 2 3 4 6 8
15 2480 6500 12880 38700 79000
30 1650 4700 9700 27370 55850
45 1475 3900 7900 23350 45600
60 1150 3250 6800 19330 39500
75 1120 3000 6000 17310 35300
90 930 2600 5400 15800 32250
105 920 2450 5100 14620 29650
120 860 2300 4800 15680 27920
150 710 2000 4100 12240 25000
180 720 1950 4000 11160 22800
210 660 1780 3700 10330 21100
240 620 1680 3490 9600 19740
270 580 1580 3250 9000 18610
300 545 1490 3000 8500 17660
450 450 1230 2500 7000 14420
600 380 1030 2130 6000 12480
Table 2
Gas Pipe Capacities
In Cu. Ft.per Hour with Pressure Drop of 0.3 in W.C. with Specific Gravity 0.60.
Table 3
Specific Gravity Conversion Factors
Multiplying factors to be used with Table 1 when the specific gravity of gas is
other than 0.60.
Natural Gas Propane Gas
Specific Specific
Gravity Factor Gravity Factor
0.55 1.04 1.50 0.633
0.60 1.00 1.53 0.626
0.65 0.962 1.60 0.612
Figure 9
Horizontal Venting - Two Pipes
METAL
SLEEVE
FIBER GLASS
INSULATION
MIN. 2"
2" MIN.
VENT TERMINATION
SUPPORT BRACKET
(where required)
(Make from 1" x 1" steel angle)
9"
9"
45
1"
METAL
SLEEVE
2" MIN.
VENT PIPE
DIAMETER
METAL FACE
PLATE
1"
Figure 10
Exhaust Vent Construction Through Combustible Walls
and Support Bracket
7
CAUTION
Gas pressure to unit heater controls must never exceed 14"
W.C. (1/2 psi).
When leak testing the gas supply piping system, the appliance
and its combination gas control must be isolated during any
pressure testing in excess of 14" W.C. (1/2 psi).
The appliance should be isolated from the gas supply piping
system by closing its field installed manual shut-off valve.
Heater Parts from ACF Greenhouses
