Carbon Monoxide Warning
Follow all the local and state codes or, in
the absence of local and state codes, the
"National Fuel Gas Code", ANSI Z223.1
(NFPA 54)- latest edition to properly
install vent system.
Failure to do so can result in death,
explosion, or carbon monoxide poisoning.
Important:
Air for combustion and ventilation must not
come from a corrosive atmosphere. Any failure due to
corrosive elements in the atmosphere is excluded from
warranty coverage.
The following types of installation (not limited to the
following) will require outdoor air for combustion due to
chemical exposure and may reduce but not eliminate
the presence of corrosive chemicals in the air:
!
beauty shops
!
photo processing labs
!
buildings with indoor pools
Nominal Iron Pipe
Length of Pipe, Feet
Size, in.
1/2
3/4
1
1-1/4
1-1/2
132
278
520
1050
1600
92
190
350
730
1100
73
152
285
590
890
63
130
245
500
760
56
115
215
440
670
50
105
195
400
610
46
96
180
370
560
43
90
170
350
530
40
84
160
320
490
38
79
150
305
460
34
72
130
275
410
31
64
120
250
380
28
59
110
225
350
26
55
100
210
320
10
20
30
40
50
60
70
80
90
100
125
150
175
200
Table 1
Natural Gas Pipe Capacity Table (Cu. Ft./Hr.)
Capacity of gas pipe of different diameters and lengths in cu. ft. per hr. with pressure drop of 0.3 in. and specific gravity
of 0.60 (natural gas).
After the length of pipe has been determined, select the pipe size which will provide the minimum cubic feet per hour
required for the gas input rating of the water heater. By formula:
Gas Input of Water Heater (BTU/HR)
Heating Value of Gas (BTU/FT³)
3
The gas input of the water heater is marked on the water heater data plate. The heating value of the gas (BTU/FT )
may be determined by consulting the local natural gas utility.
Cu. Ft. Per Hr. Required=
Nominal Iron Pipe
Size, in.
Length of Pipe, Feet
3/4
1/2
1
1-1/4
275
576
1071
2205
189
393
732
1496
152
315
590
1212
129
267
504
1039
114
237
448
913
103
217
409
834
96
196
378
771
89
185
346
724
83
173
322
677
78
162
307
630
69
146
275
567
63
132
252
511
10
20
30
40
50
60
70
80
90
100
125
150
Table 2
LP Gas Capacity Table
Maximum capacity of pipe in thousands of BTU per hour of undiluted liquefied petroleum gases (at 11 inches water
column pressure). Based on a pressure drop of 0.5 inch water column.
Example:
Input BTU requirement of the water heater 100,000 BTUH.
Total pipe length, 80 feet = 3/4" IPS required.
Additional tables are available in the latest edition of the "National Fuel Gas Code", ANSI Z223.1.
Combustion Air Supply and
Ventilation
!
water heaters installed in laundry, hobby, or
craft rooms
!
water heaters installed near chemical storage
areas
Combustion air must be free of acid-forming chemicals
such as sulfur, fluorine, and chlorine. These elements
are found in aerosol sprays, detergents, bleaches,
cleaning solvents, air fresheners, paint, and varnish
removers, refrigerants, and many other commercial and
household products. When burned, vapors from these
products form highly corrosive acid compounds. These
products should not be stored or used near the water
heater or air inlet.
Combustion and ventilation air requirements are
determined by the location of the water heater. The
water heater may be located in either an open
(unconfined) area or in a confined area or small
enclosure such as a closet or small room. Confined
spaces are areas with less than 50 cubic feet for each
1,000 BTUH of the total input for all gas-using
appliances.
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