Gas Piping; Connection Of Gas Pipe - A.O. Smith CYCLONE XHE BTH 300A Installation & Operating Instructions Manual

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 3. The figures
shown are for straight lengths of pipe at 0.5 in. W.C. (125Pa)
pressure drop, which is considered normal for low pressure systems
Note that fittings such as elbows and tees will add to the pipe
pressure drop.
DO NOT USE FLEXIBLE GAS PIPING.
MAXIMUM CAPACITY OF PIPE IN CUBIC FEET OF GAS 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 NORMAL IRON PIPE SIZES (INCHES)
IN INPUT IN THOUSANDS BTU/HR
FEET 1/2" 3/4" 1" 1 1/4" 1 1/2"
10 175 360 680 1400
20 120 250 485
30 97 200 375
40 82 170 320
50 73 151 285
60 66 138 260
70 61 125 240
80 57 118 220
90 53 110 205
100 50 103 195
125 44 93 175
150 40 84 160
175 37 77 145
200 35 72 135
LENGTH NORMAL IRON PIPE SIZES (INCHES)
IN
METERS 1/2" 3/4" 1"
3.0 51 105 199
6.1 35 73 142
9.1 28 59 110
12.2 24 50 94
15.2 21 44 83
18.3 19 40 76
21.3 18 37 70
24.4 17 35 64
27.4 16 32 60
30.5 15 30 57
38.1 13 27 51
45.7 12 25 47
53.3 11 23 42
61.0 10 21 40
THE HEATER IS NOT INTENDED FOR OPERATION AT HIGHER
THAN 11.0" WATER COLUMN (2.74 Kpa) FOR NATURAL GAS
AND 14.0" W.C. (3.49kPa) FOR PROPANE GAS SUPPLY
PRESSURE. HIGHER GAS SUPPLY PRESSURES REQUIRE
SUPPLEMENTAL REDUCING SERVICE REGULATION.
EXPOSURE TO HIGHER GAS SUPPLY PRESSURE MAY CAUSE
DAMAGE TO THE GAS CONTROLS 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.
CAUTION
TABLE 3
2" 2 1/2" 3"
2100 3960 6300 11000 23000
950 1460 2750 4360 7700 15800
770 1180 2200 3520 6250 12800
660 990 1900 3000 5300 10900
580 900 1680 2650 4750
530 810 1520 2400 4300
490 750 1400 2250 3900
460 690 1300 2050 3700
430 650 1220 1950 3450
400 620 1150 1850 3250
360 550 1020 1650 2950
325 500 950 1500 2650
300 460 850 1370 2450
280 430 800 1280 2280
INPUT IN KW
1 1/4" 1 1/2" 2" 2 1/2"
410 615 1160 1845 3221
278 428 805 1277 2255
225 346 644 1031 1830
193 290 556 878 1552
170 264 492 776 1391
155 237 445 703 1259
143 220 410 659 1142
135 202 381 600 1083
126 190 357 571 1010
117 182 337 542
105 161 299 483
95 146 278 439
88 135 249 401
82 126 234 375
WARNING
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 A SEDIMENT
TRAP OR DRIP LEG) MUST BE INCORPORATED IN THE PIPING
(SEE FIG. 14). 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 NATIONAL FUEL GAS CODE.
4"
9700
8800
8100
7500
7200
6700
6000
5500
5000
4600
3" 4"
6735 1. When connecting gas pipe to unit, apply wrench to flange only.
4626
Note: Do not use wrench on gas valve or gas bracket.
3748
3192
2. PERFORM THE GAS LEAK TEST ANY TIME WORK IS DONE
2840
ON A GAS SYSTEM TO AVOID THE POSSIBILITY OF FIRE
2577
OR EXPLOSION WITH PROPERTY DAMAGE, PERSONAL
2372
INJURY OR LOSS OF LIFE.
2196
2108
The Gas Leak Test is performed as follows: Paint pipe connections
952 1962
upstream of gas control with a rich soap and water solution to test
864 1757
for leaks before operating main burner. Bubbles indicate gas leak.
776 1610
717 1464 To stop leak, tighten pipe connections. After piping connections
688 1347
are checked, turn on main burner. With main burner in operation,
paint pipe joints (including flanges), pilot gas tubing connections
and control inlet and outlet with rich soap and water solution.
Bubbles indicate gas leak. To stop leak, tighten flange screws, joints
and pipe connections. Replace part if leak can't be stopped.
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 compound to the first two
threads. Use compounds resistant to the action of liquefied
petroleum gases.
DISCONNECT THE APPLIANCE AND ITS MANUAL GAS
SHUTOFF VALVE FROM THE GAS SUPPLY PIPING SYSTEM
DURING ANY SUPPLY PRESSURE TESTING EXCEEDING
1/2 PSIG (3.45Kpa). GAS SUPPLY LINE MUST BE CAPPED
WHEN DISCONNECTED FROM THE HEATER. FOR TEST
12
FIGURE 14

CONNECTION OF GAS PIPE