39
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 14.0" W. C. (2.62 kPa) for natural gas and
14.0" W. C. (3.49 kPa) for propane gas supply pressure, see Table
3 on page 11. 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
Figure 54
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 Figure 54. 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
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 11
or Table 12. The values given in Table 11 and Table 12 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.
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 National Fuel
Gas Code if Corrugated Stainless Steel Tubing (CSST) is used
as the gas line for this water heater.
SUPPLY GAS LINE SIZING U. S. UNITS
TABLE 11
LENGTH
IN
FEET
NORMAL IRON PIPE SIZES (INCHES)
INPUT IN THOUSANDS BTU/HR
1/2”
3/4”
1”
1 1/4” 1 1/2”
2”
10
175
360
680
1400
2100
3960
20
120
250
485
950
1460
2750
30
97
200
375
770
1180
2200
40
82
170
320
660
990
1900
50
73
151
285
580
900
1680
60
66
138
260
530
810
1520
70
61
125
240
490
750
1400
80
57
118
220
460
690
1300
90
53
110
205
430
650
1220
100
50
103
195
400
620
1150
125
44
93
175
360
550
1020
150
40
84
160
325
500
950
175
37
77
145
300
460
850
200
35
72
135
280
430
800
SUPPLY GAS LINE SIZING METRIC UNITS
TABLE 12
LENGTH
IN
METERS
NORMAL IRON PIPE SIZES (INCHES)
INPUT IN
kW
1/2”
3/4”
1”
1 1/4” 1 1/2”
2”
3.0
51
105
199
410
615
1160
6.1
35
73
142
278
428
805
9.1
28
59
110
225
346
644
12.2
24
50
94
193
290
556
15.2
21
44
83
170
264
492
18.3
19
40
76
155
237
445
21.3
18
37
70
143
220
410
24.4
17
35
64
135
202
381
27.4
16
32
60
126
190
357
30.5
15
30
57
117
182
337
38.1
13
27
51
105
161
299
45.7
12
25
47
95
146
278
53.3
11
23
42
88
135
249
61.0
10
21
40
82
126
234
