Table of Contents
Advertisement
18. GAS SUPPLY AND PIPING
GENERAL RECOMMENDATIONS
1. Be sure the gas line complies with the local codes
and ordinances, or in their absence with the
National Fuel Gas Code, ANSI Z223.1, or Natural
Gas Installation Code, CAN/CGA B149.1, or
Propane Installation Code B149.2, latest edition.
2. A sediment trap or drip leg must be installed in the
supply line to the furnace.
3. A ground joint union shall be installed in the gas
line adjacent to and upstream from the gas valve
and downstream from the manual shut-off valve.
4. An 1/8" NPT plugged tapping accessible for test
gauge connection shall be installed immediately
upstream of the gas supply connection to the
furnace for the purpose of determining the supply
gas pressure. This can be omitted if local codes
permit use of plugged tapping in gas valve inlet.
5. Install listed manual shut-off valve in the supply
gas line external to and immediately upstream of
the furnace. See Figure 12.
6. Use steel or wrought iron pipe and fittings.
7. DO NOT thread pipe too far. Valve distortion or
malfunction may result from excess pipe within the
control. Use pipe joint compound resistant to the
action of liquefied petroleum gases on male
threads only. DO NOT use Teflon tape. See
Table 5 and Figure 13.
TABLE 5
LENGTH OF STANDARD
PIPE THREADS (Inches)
f E
e f
t c
v i
e
P
p i
e
S
z i
e
f o
T
h
3
8 /
1
3
4 /
1
2 /
- -
1
9
1 /
FIGURE 13
PROPER PIPING PRACTICE
MIS-897
L
e
n
g
h t
O
v
e
a r
l l
L
e
n
g
h t
e r
a
d
f o
T
h
e r
a
d
2 /
9
1 /
6
9
1 /
6
1
3
1 /
6
6
1
8. Refer to Table 6 for Gas Pipe Sizes for natural
gas. If more than one appliance is supplied from a
single line size, capacity must equal or exceed the
combined input to all appliances, and the branch
lines feeding the individual appliances properly
sized for each input.
TABLE 6
GAS PIPE SIZES - NATURAL GAS
P
p i
e
C
a
p
a
i c
y t
L
e
n
g
h t
f o
P
p i
e
-
F
e
t e
/ 1
" 2
1
0
1
3
2
0 ,
0
0
2
0
9
2
0 ,
0
0
3
0
7
3
0 ,
0
0
4
0
6
3
0 ,
0
0
5
0
5
6
0 ,
0
0
6
0
5
0
0 ,
0
0
7
0
4
6
0 ,
0
0
8
0
4
3
0 ,
0
0
1
0
0
3
8
0 ,
0
0
CHECKING THE GAS PIPING
Before turning gas under pressure into piping, all
openings from which gas can escape should be
closed. Immediately after turning on gas, the system
should be checked for leaks. This can be done by
watching the 1/2 cubic foot test dial and allowing 4
minutes to show any movement, and by soaping each
pipe connection and watching for bubbles. If a leak is
found, make the necessary repairs immediately and
repeat the above test. The furnace must be isolated
from the gas supply piping system by closing the
manual shut-off valve on the combination gas control
valve during pressure testing of the gas supply piping
system at pressures up to 1/2 PSIG. The furnace and
its individual shut-off valve must be disconnected
from supply piping and supply piping capped during
any pressure testing of supply piping system at test
pressures in excess of 1/2 PSIG.
Defective pipes or fittings should be replaced and not
repaired. Never use a flame or fire in any form to
locate gas leaks; use a soap solution.
After the piping and meter have been checked
completely, purge the system of air. DO NOT bleed
air inside the furnace. Be sure to check and relight
all the gas pilots on other appliances that may have
been extinguished because of interrupted gas supply.
-
B
T
U
p
r e
H
o
r u
n I
p
t u
P
p i
e
S
/ 3
" 4
" 1
- 1
/ 1
" 4
2
7
8
0 ,
0
0
5
2
0
0 ,
0
0
1
0 ,
5
0
0 ,
1
9
0
0 ,
0
0
3
5
0
0 ,
0
0
7
3
0
0 ,
1
5
2
0 ,
0
0
2
8
5
0 ,
0
0
5
9
0
0 ,
1
3
0
0 ,
0
0
2
4
5
0 ,
0
0
5
0
0
0 ,
1
1
5
0 ,
0
0
2
1
5
0 ,
0
0
4
4
0
0 ,
1
0
5
0 ,
0
0
1
9
5
0 ,
0
0
4
0
0
0 ,
9
6
0 ,
0
0
1
8
0
0 ,
0
0
3
7
0
0 ,
9
0
0 ,
0
0
1
7
0
0 ,
0
0
3
5
0
0 ,
7
9
0 ,
0
0
1
5
0
0 ,
0
0
3
0
5
0 ,
Manual 2100-365
Page 19
z i
e
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Advertisement
Table of Contents
