Optional Gas Heat; Gas Pipe Sizing - Capacity Of Pipe; Side Entry Gas Piping; Bottom Entry Gas Piping - Johnson Controls ZF Series Installation Manual

5566018-YIM-B-1018

Optional gas heat

The optional gas-fired heaters have aluminized-steel or optional
stainless steel, tubular heat exchangers with spark ignition.
Note: On VAV units: individual VAV boxes must be fully open
in heating mode to ensure airflow falls within the
specified temperature rise range.
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.
Follow the "National Fuel Gas Code" Z223.1 (in U.S.A.) or the
current Gas Installation Codes CSA-B149.1 (in Canada) in all
cases unless they are superseded by local codes or gas utility
requirements.
See Table 16, Gas pipe sizing - capacity of pipe, on page 34.
The heating value of the gas may vary by locality. You must
check the value with the local gas utility.
Figure 25: Side entry gas piping
34
Figure 26: Bottom entry gas piping
Table 16:Gas pipe sizing - capacity of pipe
Length of
OPTIONAL
COIL
GUARD
SHOWN
Note: Maximum capacity of pipe in cubic feet of gas per hour
Note: There may be a local gas utility requirement specifying
Nominal iron pipe size
pipe (ft.)
3/4 in.
10 278
20 190
30 152
40 130
50 115
60 105
70 96
80 90
90 84
100 79
based upon a pressure drop of 0.3 inch W.C. and 0.6
specific gravity gas.
a minimum diameter for gas piping. All units require a 3/
4 inch pipe connection at the entrance fitting. The line
must not be sized smaller than the entrance fitting size.
Johnson Controls Ducted Systems
OPTIONAL
COIL
GUARD
SHOWN
1 in. 1-1/4 in.
520 1050
350 730
285 590
245 500
215 440
195 400
180 370
170 350
160 320
150 305