37
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
Turn off gas lines during installation.
Contact a qualified installer or service
agency for installation and service.
Excessive gas pressure to gas valve can
cause serious injury or death.
Do not use water heater with any gas
other than the gas shown on the rating
label.
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
PIPE CAP
SEDIMENT TRAP
(DIRT LEG)
figure 52
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.
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
IN
FEET
NOrmAL irON PiPE SiZES (iNCHES)
INPUT IN THoUSANDS bTU/HR
1 1/4” 1 1/2”
2”
2 1/2”
3”
4”
10
1400
2100
3960
6300
11000 23000
20
950
1460
2750
4360
7700
15800
30
770
1180
2200
3520
6250
12800
40
660
990
1900
3000
5300
10900
50
580
900
1680
2650
4750
9700
60
530
810
1520
2400
4300
8800
70
490
750
1400
2250
3900
8100
80
460
690
1300
2050
3700
7500
90
430
650
1220
1950
3450
7200
100
400
620
1150
1850
3250
6700
125
360
550
1020
1650
2950
6000
150
325
500
950
1500
2650
5500
175
300
460
850
1370
2450
5000
200
N/A
430
800
1280
2280
4600
supply gas line siZing metric units
taBle 9
LENGTH
IN
mETERS
NOrmAL irON PiPE SiZES (iNCHES)
INPUT IN kW
1 1/4” 1 1/2”
2”
2 1/2”
3”
4”
3.0
410
615
1160
1845
3221
6735
6.1
278
428
805
1277
2255
4626
9.1
225
346
644
1031
1830
3748
12.2
193
290
556
878
1552
3192
15.2
170
264
492
776
1391
2840
18.3
155
237
445
703
1259
2577
21.3
143
220
410
659
1142
2372
24.4
135
202
381
600
1083
2196
27.4
126
190
357
571
1010
2108
30.5
117
182
337
542
952
1962
38.1
105
161
299
483
864
1757
45.7
95
146
278
439
776
1610
53.3
88
135
249
401
717
1464
61.0
N/A
126
234
375
688
1347
Summary of Contents for 101 Series
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