349215-JIM-B-1008
14
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.
All gas heaters are shipped from the factory equipped
for natural gas use, but can be field converted to L.P./
Propane with Kit Model # 1NP0418. See Gas Heat
Application Data Table.
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unless superseded by local codes or gas utility require-
ments. Refer to the Pipe Sizing Table 5.
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.
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).
TABLE 3: ELECTRIC HEAT APPLICATION DATA
NOMINAL
HEATER SIZE
(KW)
VOLTAGE
3-PHASE,
60 HZ
MINIMUM CFM UNIT SIZE
15 TON
17.5 TON
20 TON
25 TON
18
208/230,460,575
4500
6000
6000
7500
36
208/230,460,575
4500
54
208/230
5000
460,575
4500
72
208/230
5000
460,575
4500
TABLE 4: 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
1
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, 17.5, 20 & 25 Ton
279
20
50
400
200
360
180
320
281
15, 17.5, 20 & 25 Ton
372
30
60
1.
On VAV units, individual VAV boxes must be full open in heating mode to insure airflow falls within
temperature rise range.
TABLE 5: PIPE SIZING
Length in Feet
Nominal Iron Pipe Size
1 in.
1-1/4 in.
10
520
1,050
20
350
730
30
285
590
40
245
500
50
215
440
60
195
400
70
180
370
80
170
350
90
160
320
100
150
305
