Supply Gas Line Installation - A.O. Smith 101 Series Instruction Manual

supply gas line installation

Contact your local gas utility company to ensure that adequate
gas service is available and to review applicable installation
codes for your area.
Be sure that the gas meter has sufficient capacity to supply the
rated gas input of the water heater as well as the requirements
of all other gas fired equipment supplied by the meter. if the
gas meter is undersized, the gas company will have to install a
properly sized gas meter.
Fire and Explosion Hazard
Do not use water heater with any gas
other than the gas shown on the rating
label.
Excessive gas pressure to gas valve can
cause serious injury or death.
Turn off gas lines during installation.
Contact a qualified installer or service
agency for installation and service.
make sure gas supplied is same type listed on the water heater's
rating label.
The water heaters covered in this manual are not intended for
operation at higher than 10.0" W. C. (2.49 kPa) for natural gas
and 12.0" W. C. (2.99 kPa) for propane gas supply pressure,
see Table 4 on page 13. The water heaters covered in this manual
require supply gas regulators to maintain required supply gas
pressure. 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 malfunction of the supply system the water heater's
gas valve must be checked for safe operation by a Qualified
Service Agency.
Ensure supply regulator vent lines and the safety vent valves are
protected against blockage. These are components of the gas
supply system, not the water heater. Vent blockage may occur
during ice storms.
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.
REGULATED GAS
SUPPLY LINE
MAIN GAS
SHUTOFF VALVE
TEE FITTING
SEDIMENT TRAP
(DIRT LEG)
PIPE CAP
Ensure all gas pipe is clean on the inside before installation. To trap
any dirt or foreign material in the gas supply line a sediment trap
(dirt leg) must be installed as shown in Figure 52. The sediment
trap must be readily accessible and not subject to freezing
conditions. install in accordance with the recommendations of
the local gas utility company.
figure 52
gas line siZing
do not use flexible gas piping.
minimum required supply gas line sizes are shown in Table 5 on
page 13. Depending on the developed equivalent length and/or the
number of appliances connected to a common main, the size of
supply gas lines may have to be increased.
Size the supply/main gas line(s) in accordance with Table 8 or
Table 9. The values given in Table 8 and Table 9 are for straight
lengths of iron pipe at 0.5" W. C. (125 Pa) 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.
supply gas line siZing u. s. units
taBle 8
LENGTH NOrmAL irON PiPE SiZES (iNCHES)
IN INPUT IN THoUSANDS bTU/HR
FEET 1 1/4" 1 1/2"
10 1400 2100
20 950 1460
30 770 1180
40 660 990
50 580 900
60 530 810
70 490 750
80 460 690
90 430 650
100 400 620
125 360 550
150 325 500
175 300 460
200 N/A 430
supply gas line siZing metric units
taBle 9
LENGTH NOrmAL irON PiPE SiZES (iNCHES)
IN
mETERS 1 1/4" 1 1/2"
3.0 410 615
6.1 278 428
9.1 225 346
12.2 193 290
15.2 170 264
18.3 155 237
21.3 143 220
24.4 135 202
27.4 126 190
30.5 117 182
38.1 105 161
45.7 95 146
53.3 88 135
61.0 N/A 126
37
2" 2 1/2" 3"
3960 6300 11000 23000
2750 4360 7700 15800
2200 3520 6250 12800
1900 3000 5300 10900
1680 2650 4750 9700
1520 2400 4300 8800
1400 2250 3900 8100
1300 2050 3700 7500
1220 1950 3450 7200
1150 1850 3250 6700
1020 1650 2950 6000
950 1500 2650 5500
850 1370 2450 5000
800 1280 2280 4600
INPUT IN kW
2" 2 1/2" 3"
1160 1845 3221 6735
805 1277 2255 4626
644 1031 1830 3748
556 878 1552 3192
492 776 1391 2840
445 703 1259 2577
410 659 1142 2372
381 600 1083 2196
357 571 1010 2108
337 542 952 1962
299 483 864 1757
278 439 776 1610
249 401 717 1464
234 375 688 1347
4"
4"