5120416-XIM-C-0216
20
Johnson Controls Unitary Products
Optional Gas Heat
These gas-fired heaters have aluminized-steel or optional stainless steel, tubular heat exchangers with spark ignition with proven
pilot.
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followed in all cases unless superseded by local codes or gas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:
There may be a local gas utility requirement specifying
a minimum diameter for gas piping. All units require a
one-inch pipe connection at the entrance fitting.
Figure 15: External Supply Connection External Shut-Off
Figure 16: Bottom Supply Connection External Shut-Off
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.
Gas Connection
The gas supply line can be routed within the space and roof curb,
exiting through the unit’s basepan. Refer to Figure 5 for the gas
piping inlet location. Typical supply piping arrangements are
Table 8:
Gas Heat Application Data
0 To
2,000 Feet
Above
Sea Level
2,000 To
4,500 Feet
Above
Sea Level
Output Capacity (Mbh)
Available
on Models
Gas
Rate
(Ft./Hr.)
Temp.
Rise ºF
At
Full Input
0 To
2,000 Feet
Above
Sea Level
2,000 To
4,500 Feet
Above
Sea Level
Max.
Min.
Max.
Min.
Max.
Max.
Min.
Max.
300
150
270
135
240
213
15, 20 & 25 Ton
279
20
50
350
175
320
160
280
241
25 Ton
326
30
60
Drip Leg
Main
Manual
Shut-off
Valve
Table 9:
Gas Pipe Sizing - Capacity of Pipe
Length of
Pipe ft. (m)
Nominal Iron Pipe Size
1 in.
1-1/4 in.
10 (3)
520 (14.7)
1050 (29.7)
20 (6)
350 (9.9)
730 (20.6)
30 (9.1)
285 (8)
590 (16.7)
40 (12.1)
245 (6.9)
500 (14.1)
50 (15.2)
215 (6)
440 (12.4)
60 (18.2)
195 (5.5)
400 (12.4)
70 (21.3)
180 (5)
370 (10.4)
80 (24.3)
170 (4.8)
350 (9.9)
90 (27.4)
160 (4.5)
320 (9)
100 (30.4)
150 (4.2)
305 (8.6)
Drip Leg
Main
Manual
Shut-off
Valve
