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hood assembly over flue panel. Orient screw holes in flue
hood with holes in the flue panel.
3. Secure flue hood to flue panel by inserting a single screw on
the top flange and the bottom flange of the hood.
Step 8 — Install Gas Piping
The gas supply pipe enters the unit through the access hole
provided. The gas connection to the unit is made to the 1/2- -in.
(12.7 mm) FPT gas inlet on the gas valve.
Install a gas supply line that runs to the heating section. Refer to
the NFGC for gas pipe sizing. Do not use cast- -iron pipe. It is
recommended that a black iron pipe is used. Check the local utility
for recommendations concerning existing lines. Size gas supply
piping for 0.5 IN. W.C. maximum pressure drop. Never use pipe
smaller than the 1/2- -in. (12.7 mm) FPT gas inlet on the unit gas
valve.
For natural gas applications, the gas pressure at unit gas connection
must not be less than 4.0 IN. W.C. or greater than 13 IN. W.C.
while the unit is operating. For propane applications, the gas
pressure must not be less than 11.0 IN. W.C. or greater than 13 IN.
W.C. at the unit connection.
A 1/8- -in. (3.2 mm) NPT plugged tapping, accessible for test gauge
connection, must be installed immediately upstream of the gas
supply connection to the gas valve.
When installing the gas supply line, observe local codes pertaining
to gas pipe installations. Refer to the NFPA 54/ANSI Z223.1 latest
edition (in Canada, CAN/CGA B149.1).
NOTE: In the state of Massachusetts:
1. Gas supply connections MUST be performed by a licensed
plumber or gas fitter.
2. When flexible connectors are used, the maximum length
shall not exceed 36 inches (915 mm).
3. When lever handle type manual equipment shutoff valves
are used, they shall be T- -handle valves.
4. The use of copper tubing for gas piping is NOT approved
by the state of Massachusetts.
In the absence of local building codes, adhere to the following
pertinent recommendations:
1. Avoid low spots in long runs of pipe. Grade all pipe 1/4 in.
(6.35 mm) for every 15 ft (4.6 m) of length to prevent traps.
Grade all horizontal runs downward to risers. Use risers to
connect to heating section and to meter.
2. Protect all segments of piping system against physical and
thermal damage. Support all piping with appropriate straps,
NOMINAL
INTERNAL
IRON PIPE
DIAMETER
10
SIZE (IN.)
(IN.)
(3)
1/2
.622
175
3/4
.824
360
1
1.049
680
1--- 1/4
1.380
1400
1--- 1/2
1.610
2100
*Capacity of pipe in cu ft of gas per hr for gas pressure of 0.5 psig or less. Pressure drop of 0.5 ---IN. W.C. (based on a 0.60 specific gravity gas). Refer to Table 2
and National Fuel Gas Code NFPA 54/ANSI Z223.1.
{ This length includes an ordinary number of fittings.
Table 2 – Maximum Gas Flow Capacity*
20
30
40
50
(6)
(9)
(12)
(15)
120
97
82
73
250
200
170
151
465
375
320
285
950
770
600
580
1460
1180
990
900
hangers, etc. Use a minimum of one hanger every 6 ft (1.8
m).
For
pipe
sizes larger
recommendations of national codes.
3. Apply joint compound (pipe dope) sparingly and only to
male threads of joint when making pipe connections. Use
only pipe dope that is resistant to action of liquefied
petroleum gases as specified by local and/or national codes.
Never use Teflon tape.
4. Install sediment trap in riser leading to heating section (See
Fig. 9). This drip leg functions as a trap for dirt and
condensate.
5. Install an accessible, external, manual main shutoff valve in
gas supply pipe within 6 ft (1.8 m) of heating section.
6. Install ground- -joint union close to heating section between
unit manual shutoff and external manual main shut- -off
valve.
7. Pressure test all gas piping in accordance with local and
national plumbing and gas codes before connecting piping
to unit.
OUT
Fig. 9 - - Sediment Trap
NOTE: Pressure test the gas supply system after the gas supply
piping is connected to the gas valve. The supply piping must be
disconnected from the gas valve during the testing of the piping
systems when test pressure is in excess of 0.5 psig. Pressure test the
gas supply piping system at pressures equal to or less than 0.5 psig.
The unit heating section must be isolated from the gas piping
system by closing the external main manual shutoff valve and
slightly opening the ground- -joint union.
LENGTH OF PIPE FT (m)†
60
70
80
90
(18)
(21)
(24)
(27)
66
61
57
53
138
125
118
110
260
240
220
205
530
490
460
430
810
750
690
650
12
than
1/2
in., follow
IN
TEE
NIPPLE
CAP
100
125
150
175
(30)
(38)
(46)
(53)
50
44
40
—
103
93
84
77
195
175
160
145
400
360
325
300
620
550
500
460
C99020
200
(61)
—
72
135
280
430
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