21
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
and
. The sizes shown are for straight lengths of pipe
at 0.5 in. W.C. pressure drop, which is considered normal
for low pressure systems. Note: Fittings such as elbows,
tees and line regulators will add to the pipe pressure
drop. Also refer to the current editions of the
National Fuel
Gas Code (NFPA 54)
.
Make sure gas supplied is same type listed on model
rating plate. The inlet gas pressure must not exceed 14
inch water column (2.6 kPa) for natural and propane
(L.P.) gas. The minimum inlet gas pressure shown on
rating plate is that which will permit firing at rated input.
If the gas control valve is subjected to pressures
exceeding 1/2 pound per square inch (3.5 kPa), the
damage to the gas control valve could result in a fire or
explosion from leaking gas.
If the main gas line shut-off serving all gas appliances is
used, also turn “off” the gas at each appliance. Leave all
gas appliances shut “off” until the water heater installation
is complete.
A gas line of sufficient size must be run to the water
heater. Consult the current edition of
National Fuel
Gas Code ANSI Z223.1/NFPA 54
and your gas supplier
concerning pipe size.
The gas piping must include the following:
•
A readily accessible manual shut off valve in the gas
supply line serving the water heater, and
•
A sediment trap ahead of the gas control valve to help
prevent dirt and foreign materials from entering the
gas control valve.
•
A flexible gas connector or a ground joint union
between the shut off valve and control valve to permit
servicing of the unit.
Be sure to check all the gas piping for leaks before
lighting the water heater. Use a soapy water solution, not
a match or open flame. Rinse off soapy solution and wipe
dry.
The minimum inlet gas pressure shown on the rating
plate is that which will permit firing at the rated input.
GAS SUPPLY LINE SIZES (IN INCHES)* MAXIMUM CAPACITY
OF PIPE IN CUBIC FEET PER HOUR
TABLE 2. INPUT IN THOUSANDS (BTU/HR)
LENGTH
IN
FEET
NOMINAL IRON PIPE SIZES (INCHES)
1/2
"
3/4
"
1
"
1 1/4
"
1 1/2
"
2
"
2 1/2
"
3
"
4
"
10
175
360
680
1400
2100
3960
6300
11000
23000
20
120
250
465
950
1460
2750
4360
7700
15800
30
97
200
375
770
1180
2200
3520
6250
12800
40
82
170
320
660
990
1900
3000
5300
10900
50
73
151
285
580
900
1680
2650
4750
9700
60
66
138
260
530
810
1520
2400
4300
8800
70
61
125
240
490
750
1400
2250
3900
8100
80
57
118
220
460
690
1300
2050
3700
7500
90
53
110
205
430
650
1220
1950
3450
7200
100
50
103
195
400
620
1150
1850
3250
6700
125
44
93
175
360
550
1020
1650
2950
6000
150
40
84
160
325
500
950
1500
2650
5500
175
37
77
145
300
460
850
1370
2450
5000
200
35
72
135
280
430
800
1280
2280
4600
TABLE 3. INPUT IN KW
LENGTH
IN
METERS
NOMINAL IRON PIPE SIZES (INCHES)
1/2
"
3/4
"
1
"
1 1/4
"
1 1/2
"
2
"
2 1/2
"
3
"
4
"
3
51
105
199
410
615
1160
1845
3221
6735
6
35
73
142
278
428
805
1277
2255
4626
9
28
59
110
225
346
644
1031
1830
3748
12
24
50
94
193
290
556
878
1552
3192
15
21
44
83
170
264
492
776
1391
2840
18
19
40
76
155
237
445
703
1259
2577
21
18
37
70
143
220
410
659
1142
2372
24
17
35
64
135
202
381
600
1083
2196
27
16
32
60
126
190
357
571
1010
2108
31
15
30
57
117
182
337
542
952
1962
38
13
27
51
105
161
299
483
864
1757
46
12
25
47
95
146
278
439
776
1610
53
11
23
42
88
135
249
401
717
1464
61
10
21
40
82
126
234
375
688
1347
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