9
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. 7). 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 (1829mm) 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.
8. Check for gas leaks at the field--installed and
factory--installed gas lines after all piping connections
have been completed. Use soap--and--water solution
(or method specified by local codes and/or regulations).
FIGURE 7
Sediment Trap
OUT
TEE
NIPPLE
CAP
IN
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.
Table 1
—
PIPING SIZES
NOMINAL
IRON PIPE
SIZE (IN.)
INTERNAL
DIAMETER
(IN.)
LENGTH OF PIPE (FT)†
10
20
30
40
50
60
70
80
90
100
125
150
175
200
1/2
.622
175
120
97
82
73
66
61
57
53
50
44
40
—
—
3/4
.824
360
250
200
170
151
138
125
118
110
103
93
84
77
72
1
1.049
680
465
375
320
285
260
240
220
205
195
175
160
145
135
1--1/4
1.380
1400
950
770
600
580
530
490
460
430
400
360
325
300
280
1--1/2
1.610
2100
1460
1180
990
900
810
750
690
650
620
550
500
460
430
*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. wc (based on a 0.60 specific
gravity gas). Refer to Table, National Fire Protection Association NFPA 54.
{
This length includes an ordinary number of fittings.
FIRE OR EXPLOSION HAZARD
Failure to follow this warning could result in personal
injury, death and/or property damage.
--Connect gas pipe to unit using a backup wrench to avoid
damaging gas controls.
--Never purge a gas line into a combustion chamber.
Never test for gas leaks with an open flame. Use a
commercially available soap solution made specifically for
the detection of leaks to check all connections.
--Use proper length of pipe to avoid stress on gas control
manifold.
--If a flexible connector is required or allowed by authority
having jurisdiction, black iron pipe shall be installed at
furnace gas valve and extend a minimum of 2 in. (51mm)
outside furnace casing.
--If codes allow a flexible connector, always use a new
connector. do not use a connector which has previously
serviced another gas appliance.
!
WARNING