Supply Gas Line Installation - State Water Heaters 301 Series Instruction Manual

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 Table
and are for straight lengths
Table 15
National Fuel Gas Code
1" 1 1/4" 1 1/2" 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
160 325 500 950
145 300 460 850
135 280 430 800
INPUT IN kW
1" 1 1/4" 1 1/2" 2"
199 410 615 1160
142 278 428 805
110 225 346 644
94 193 290 556
83 170 264 492
76 155 237 445
70 143 220 410
64 135 202 381
60 126 190 357
57 117 182 337
51 105 161 299
47 95 146 278
42 88 135 249
40 82 126 234