Johnson Controls 341426-BIM-A-0108 - Manual (Page 8)

341426-BIM-A-0108
8 Johnson Controls Unitary Products
GAS PIPING
Proper sizing of gas piping depends on the cubic feet per
hour of gas flow required, specific gravity of the gas and the
length of run. National Fuel Gas Code Z223.1 or CAN/CGA
B149.1 or .2 should be followed in all cases unless super-
seded by local codes or gas company requirements. Refer to
Tables 5 and 6.
The heating value of the gas may differ with locality. The
value should be checked with the local gas utility.
NOTE: There may be a local gas utility requirement specify-
ing a minimum diameter for gas piping. All units
require a 1/2 inch pipe connection at the gas valve.
GAS CONNECTION
The gas supply line can be routed through the hole located
on the left side of the unit. Refer to Figure 7 to locate these
access openings. Typical supply piping arrangements are
shown in Figure 5.
Gas piping recommendations:
1. A drip leg and a ground joint union must be installed in
the gas piping.
2. When required by local codes, a manual shut-off valve
may have to be installed outside of the unit.
3. Use wrought iron or steel pipe for all gas lines. Pipe dope
should be applied sparingly to male threads only.
.
FIGURE 5 - EXTERNAL SUPPLY CONNECTION
EXTERNAL SHUT-OFF
1 / 2 x 1 / 2 G A S C O C K
1 / 2 x 1 / 2 U N I O N
A U T O M A T I C
G A S V A L V E
D R I P L E G
1 / 2 - 1 4 N P T
TABLE 5: NATURAL GAS PIPE SIZING CHART
1
1. Maximum capacity of pipe in cubic feet of gas per hour (based
upon a pressure drop of 0.3 inch water column and 0.6 specific
gravity gas).
LENGTH
IN FEET
NOMINAL INCHES IRON PIPE SIZE
1/2” 3/4” 1” 1-1/4”
10 132 278 520 1,050
20 92 190 350 730
30 73 152 285 590
40 63 130 245 500
50 56 115 215 440
60 50 105 195 400
70 46 96 180 370
80 43 90 170 350
90 40 84 160 320
100 38 79 150 305
TABLE 6: PROPANE (LP) GAS PIPE SIZING
CHART
1
1. Maximum capacity of pipe in thousands of BTU per hour (based
upon a pressure drop of 0.5 inch water column).
LENGTH
IN FEET
NOMINAL INCHES IRON PIPE SIZE
1/2” 3/4” 1” 1-1/4”
10 275 567 1,071 2,205
20 189 393 732 1,496
30 152 315 590 1,212
40 129 267 504 1,039
50 114 237 448 913
60 103 217 409 834
70 96 196 378 771
80 89 185 346 724
90 83 173 322 677
100 78 162 307 630