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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.
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"
10
175
360 680 1400
20
120
250 465
950
30
97
200 375
770
40
82
170 320
660
50
73
151 285
580
60
66
138 260
530
70
61
125 240
490
80
57
118 220
460
90
53
110 205
430
100
50
103 195
400
125
44
93 175
360
150
40
84 160
325
175
37
77 145
300
200
35
72 135
280
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.
WARNING
2"
2 1/2"
3"
2100 3960 6300 11000 23000
1460 2750 4360
7700 15800
1180 2200 3520
6250 12800
990 1900 3000
5300 10900
900 1680 2650
4750
810 1520 2400
4300
750 1400 2250
3900
690 1300 2050
3700
650 1220 1950
3450
620 1150 1850
3250
550 1020 1650
2950
500
950 1500
2650
460
850 1370
2450
430
800 1280
2280
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
4"
9700
Gas line purging is required with new piping or systems in which
8800
air has entered.
8100
7500
7200
PURGING SHOULD BE PERFORMED BY PERSONS
6700
EXPERIENCED IN THIS TYPE GAS SERVICE. TO AVOID RISK
6000
OF FIRE OR EXPLOSION, PURGE DISCHARGE MUST NOT
5500
ENTER CONFINED AREAS OR SPACES WHERE IGNITION CAN
5000
OCCUR. THE AREA MUST BE WELL VENTILATED AND ALL
4600
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
plate. The regulator is factory adjusted to deliver gas to burner
at correct water column pressure allowing for a nominal pressure
drop through the controls.
The minimum gas supply pressure for input adjustment must not
be less than 4.5" w.c. for natural gas.
9
FIGURE 9
PURGING
CAUTION
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