66389-BIM-C-1208
Johnson Controls Unitary Products
21
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should be followed in all cases unless superseded by local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 13. 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 12: GAS HEAT APPLICATION DATA
Unit
Input (MBH)
Output (MBH)
Temp Rise
(
°
F)
Size
Opt.
-12
15
180
144
10-40
20
240
192
20-50
FIGURE 20 - 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 21 - BOTTOM ENTRY GAS PIPING
TABLE 13: 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
