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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 14.0" W. C. (2.62 kPa) for natural gas and
14.0" W. C. (3.49 kPa) for propane gas supply pressure, see
(page 11). The water heaters covered in this manual require
4
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
PIPE CAP
Figure 54. Supply Gas Line Installation
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 must be installed as shown in
must be readily accessible and not subject to freezing conditions.
Install in accordance with the recommendations of the local gas
utility company.
Table
. The sediment trap
Figure 54
GAS LINE SIZING
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
. The values given in
15
Table 14
of iron pipe at 0.5" W. C. (125 Pa) pressure drop, which is considered
normal for low pressure systems.
Note: Fittings such as elbows and tees will add to the
pipe pressure drop.
Schedule-40 Steel or wrought-iron pipe is the preferred material for
the gas line of this water heater. It is imperative to follow the sizing
recommendations in the latest version of the
if corrugated stainless steel tubing (CSST) is used as the gas line
for this water heater.
Table 14. SUPPLY GAS LINE SIZING U. S. UNITS
NORMAL IRON PIPE SIZES (INCHES)
LENGTH
INPUT IN THOUSANDS BTU/HR
IN
FEET
1/2"
3/4"
10
175
360
20
120
250
30
97
200
40
82
170
50
73
151
60
66
138
70
61
125
80
57
118
90
53
110
100
50
103
125
44
93
150
40
84
175
37
77
200
35
72
Table 15. SUPPLY GAS LINE SIZING METRIC UNITS
NORMAL IRON PIPE SIZES (INCHES)
LENGTH
IN
METERS
1/2"
3/4"
3.0
51
105
6.1
35
73
9.1
28
59
12.2
24
50
15.2
21
44
18.3
19
40
21.3
18
37
24.4
17
35
27.4
16
32
30.5
15
30
38.1
13
27
45.7
12
25
53.3
11
23
61.0
10
21
40
or
Table 14
and
are for straight lengths
Table 15
National Fuel Gas Code
1"
1 1/4"
1 1/2"
680
1400
2100
3960
485
950
1460
2750
375
770
1180
2200
320
660
990
1900
285
580
900
1680
260
530
810
1520
240
490
750
1400
220
460
690
1300
205
430
650
1220
195
400
620
1150
175
360
550
1020
160
325
500
145
300
460
135
280
430
INPUT IN kW
1"
1 1/4"
1 1/2"
199
410
615
1160
142
278
428
110
225
346
94
193
290
83
170
264
76
155
237
70
143
220
64
135
202
60
126
190
57
117
182
51
105
161
47
95
146
42
88
135
40
82
126
Table
2"
950
850
800
2"
805
644
556
492
445
410
381
357
337
299
278
249
234
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