9
GAS PIPING
Contact your local gas service company to ensure that adequate
gas service is available and to review applicable installation
codes for your area.
Size the main gas line in accordance with Table 2. The figures
shown are for straight lengths of pipe at 0.5 in. W.C. pressure
drop, which is considered normal for low pressure systems.
Note: Fittings such as elbows, tees and line regulators will add
to the pipe pressure drop. Also refer to the latest version of the
National Fuel Gas Code.
WARNING
THE HEATER IS NOT INTENDED FOR OPERATION AT HIGHER
THAN 14.0" W.C.(3.48 kPa) - NATURAL GAS, 14.0" W.C.(3.48kPa)
EXPOSURE TO HIGHER SUPPLY PRESSURE MAY CAUSE
DAMAGE TO THE GAS VALVE WHICH COULD RESULT IN FIRE
OR EXPLOSION. IF OVERPRESSURE HAS OCCURRED SUCH
AS THROUGH IMPROPER TESTING OF GAS LINES OR
EMERGENCY MALFUNCTION OF THE SUPPLY SYSTEM, THE GAS
VALVE MUST BE CHECKED FOR SAFE OPERATION. MAKE SURE
THAT THE OUTSIDE VENTS ON THE SUPPLY REGULATORS AND
THE SAFETY VENT VALVES ARE PROTECTED AGAINST
BLOCKAGE. THESE ARE PARTS OF THE GAS SUPPLY SYSTEM,
NOT THE HEATER. VENT BLOCKAGE MAY OCCUR DURING ICE
STORMS.
TABLE 2 - GAS SUPPLY LINE SIZES (IN INCHES)*
MAXIMUM CAPACITY OF PIPE IN CUBIC FEET PER HOUR
(Based upon a Pressure Drop of 0.5 inch Water Column and
0.6 specific Gravity Gas and max. gas pressure of 0.5 psig)
LENGTH
NOMINAL IRON PIPE SIZES (INCHES)
IN FEET 1/2" 3/4" 1" 1 1/4" 1 1/2" 2" 2 1/2"
3"
4"
10
175
360 680 1400
2100
3960 6300 11000 23000
20
120
250 465
950
1460
2750 4360
7700 15800
30
97
200 375
770
1180
2200 3520
6250 12800
40
82
170 320
660
990
1900 3000
5300 10900
50
73
151 285
580
900
1680 2650
4750
9700
60
66
138 260
530
810
1520 2400
4300
8800
70
61
125 240
490
750
1400 2250
3900
8100
80
57
118 220
460
690
1300 2050
3700
7500
90
53
110 205
430
650
1220 1950
3450
7200
100
50
103 195
400
620
1150 1850
3250
6700
125
44
93 175
360
550
1020 1650
2950
6000
150
40
84 160
325
500
950 1500
2650
5500
175
37
77 145
300
460
850 1370
2450
5000
200
35
72 135
280
430
800 1280
2280
4600
IT IS IMPORTANT TO GUARD AGAINST GAS VALVE FOULING
FROM CONTAMINANTS IN THE GAS WAYS. SUCH FOULING MAY
CAUSE IMPROPER OPERATION, FIRE OR EXPLOSION.
IF COPPER SUPPLY LINES ARE USED THEY MUST BE
INTERNALLY TINNED AND CERTIFIED FOR GAS SERVICE. BEFORE
ATTACHING THE GAS LINE, BE SURE THAT ALL GAS PIPE IS
CLEAN ON THE INSIDE.
TO TRAP ANY DIRT OR FOREIGN MATERIAL IN THE GAS SUPPLY
LINE, A DIRT LEG (SOMETIMES CALLED SEDIMENT TRAP OR
DRIP LEG) MUST BE INCORPORATED IN THE PIPING (SEE FIG.
9). THE DIRT LEG MUST BE READILY ACCESSIBLE AND NOT
SUBJECT TO FREEZING CONDITIONS. INSTALL IN
ACCORDANCE WITH RECOMMENDATIONS OF SERVING GAS
SUPPLIERS. REFER TO THE LATEST VERSION OF THE NATIONAL
FUEL GAS CODE.
To prevent damage, care must be taken not to apply too much
torque when attaching gas supply pipe to gas valve inlet.
Apply joint compounds (pipe dope) sparingly and only to the
male threads of pipe joints. Do not apply compounds to the first
two threads. Use compounds resistant to the action of liquefied
petroleum gases.
BEFORE PLACING THE HEATER IN OPERATION, CHECK FOR GAS
LEAKAGE.
Use soap and water solution or other material
acceptable for the purpose in locating the leaks.
DO NOT USE
MATCHES, CANDLES, FLAME OR OTHER SOURCES OF IGNITION
FOR THIS PURPOSE.
DISCONNECT THE HEATER AND ITS MANUAL GAS SHUTOFF
VALVE FROM THE GAS SUPPLY PIPING SYSTEM DURING ANY
SUPPLY PRESSURE TESTING EXCEEDING 1/2 PSIG. GAS
SUPPLY LINE MUST BE CAPPED WHEN DISCONNECTED FROM
THE HEATER FOR TEST PRESSURES OF 1/2 PSIG OR LESS. THE
APPLIANCE NEED NOT BE DISCONNECTED, BUT MUST BE
ISOLATED FROM THE SUPPLY PRESSURE TEST BY CLOSING
THE MANUAL GAS SHUTOFF VALVE.
GAS PIPING AND DIRT LEG INSTALLATION
FIGURE 9
PURGING
Gas line purging is required with new piping or systems in which
air has entered.
CAUTION
PURGING SHOULD BE PERFORMED BY PERSONS EXPERIENCED
IN THIS TYPE GAS SERVICE. TO AVOID RISK OF FIRE OR
EXPLOSION, PURGE DISCHARGE MUST NOT ENTER CONFINED
AREAS OR SPACES WHERE IGNITION CAN OCCUR. THE AREA
MUST BE WELL VENTILATED AND ALL SOURCES OF IGNITION
MUST BE INACTIVATED OR REMOVED.
GAS METER SIZE — NATURAL GASES ONLY
Be sure the gas meter has sufficient capacity to supply the full
rated gas input of the water heater as well as the requirements
of all other gas fired equipment supplied by the meter. If gas
meter is too small, ask the gas company to install a larger meter
having adequate capacity.
GAS PRESSURE REGULATOR
The gas pressure regulator is built into the gas valve and is
equipped to operate on the gas specified on model and rating
