State Water Heaters SUF 60120 THRU, Instruction Manual

Page: 40 / 80

40
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
4
(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. 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
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 14
or
Table
15
. The values given in
Table 14
and
Table 15
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:
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.
Table 14. SUPPLY GAS LINE SIZING U. S. UNITS
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
Table 15. SUPPLY GAS LINE SIZING METRIC UNITS
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