127878-YIM-C-1208
26 Johnson Controls Unitary Products
OPTIONAL GAS HEAT
These gas-fired heaters have aluminized-steel or optional
stainless steel, tubular heat exchangers with spark ignition.
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 (in U.S.A.) or
the current Gas Installation Codes CSA-B149.1 (in Canada)
should be followed in all cases unless superseded by local
codes or gas utility requirements. Refer to the Pipe Sizing
Table 17. The heating value of the gas may differ with locality.
The value should be checked with the local gas utility.
NOTE: Maximum capacity of pipe in cubic feet of gas per
hour based upon a pressure drop of 0.3 inch W.C.
and 0.6 specific gravity gas.
NOTE: There may be a local gas utility requirement specify-
ing a minimum diameter for gas piping. All units
require a 3/4 inch pipe connection at the entrance
fitting. Line should not be sized smaller than the
entrance fitting size.
TABLE 16: GAS APPLICATION DATA
Unit Opt. Input (MBH) Output (MBH)
Temp Rise
(°F)
090
10 120 96 15-45
15 180 144 30-60
120
15 180 144 20-50
20 240 192 30-60
150
15 180 144 10-40
20 240 192 20-50
FIGURE 26 - SIDE ENTRY GAS PIPING
O P T I O N A L
C O I L
G U A R D
S H O W N
FIGURE 27 - BOTTOM ENTRY GAS PIPING
TABLE 17: GAS PIPE SIZING - CAPACITY OF PIPE
Length of
Pipe (ft.)
Nominal Iron Pipe Size
3/4 in. 1 in. 1-1/4 in.
10
278 520 1050
20
190 350 730
30
152 285 590
40
130 245 500
50
115 215 440
60
105 195 400
70
96 180 370
80
90 170 350
90
84 160 320
100
79 150 305
OPTIONAL
COIL
GUARD
SHOWN
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