16
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 Table 3. The figures 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) or Natural Gas and Propane Installation Code (CAN/CSA B149.1).
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
or the Natural Gas and Propane Installation Code CAN/CSA B149.1
and your gas supplier concerning pipe size.
There must be:
• 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.
taBle 3. Gas supplY lIne sIzes (In Inches)*
MaXIMuM capacItY of pIpe In cuBIc feet per hour
lenGth
In
feet
noMInal Iron pIpe sIzes (Inches)
Input In thousands (Btu/hr)
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 4.
lenGth
In
Meters
noMInal Iron pIpe sIzes (Inches)
Input In Kw
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
Use pipe joint compound or teflon tape marked as being resistant to
the action of petroleum [Propane (L.P.)] gases.
The water heater and its gas connection must be leak tested before
placing the water heater in operation.
The water heater and its individual shut-off valve shall be
disconnected from the gas supply piping system during any pressure
testing of that system at test pressures in excess of 1/2 pound per
square inch (3.5 kPa). It shall be isolated from the gas supply piping
system by closing its individual manual shut-off valve during any
pressure testing of the gas supply piping system at test pressures
equal to or less than 1/2 pound per square inch (3.5 kPa).
Connecting the gas piping to the gas control valve of the water heater
can be accomplished by either of the two methods shown in Figures
15 and 16.
fIGure 15. Gas pIpInG wIth fleXIBle connector.
fIGure 16. Gas pIpInG wIth all
BlacK Iron pIpe to Gas control.
