Gas Supply Piping - RBI LCD Series Installation & Operation Manual

Page 22

GAS SUPPLY PIPING

WARNING: Check the boiler/water heater rating
plate to make sure that the boiler/water heater
is for the type of gas that will be used. If it isn't,
do not connect the boiler/water heater to the gas
supply. Failure to comply with this warning can
result in extensive property damage, severe
personal injury or death!
The LCD comes from the factory ready to be piped to
the gas supply. If for any reason the boiler/water heater
is not for the type of gas available at the installation site,
call your RBI Water Heaters representative to resolve
the problem.
Note: A minimum gas supply pressure of 6 in,
152 mm, W.C. natural or 11 in, 279 mm W.C. propane
and maximum 14 in, 356 mm W.C. natural or
propane, must be available at the safety shutoff
valve inlet with the unit(s) operating.
Table 9 should be used to ensure that the gas supply
piping is sized properly. If more than one appliance is
supplied by the same supply pipe, the piping must be
sized based on the maximum possible demand. Do not
neglect the pressure drop due to pipe fittings. Table 9
should be used in conjunction with Table 10 to ensure
that the gas supply piping has the capacity to meet the
demand.
Figure 16 depicts the proper way to connect the boiler/
water heater to the gas supply piping. Provide a
sediment trap at the bottom of the vertical section of the
gas supply pipe upstream of the gas controls.
A ground joint union should be installed between the
boiler gas controls and the supply piping. Each of these
items are needed to ensure long life and ease of
servicing. Always use a pipe sealant that is suitable for
use with LP gas.
Table 9 - Gas Pipe Capacity
Maximum pipe capacity in ft
at a pressure of 0.5 psig or less and a 0.3" WC pressure drop.
Nominal
Iron Pipe 10 20
Size, (in)
Maximum gas volume of pipe, (ft
"
3 / 278 190 152
4
520 350 285
1"
"
1 1050 730 590
1 /
4
"
1 1 / 1600 1100 890
2
2" 3050 2100 1650 1450 1270 1150 990
"
2 1 / 4800 3300 2700 2300 2000 1850 1600 1400 1130
2
3" 8500 5900 4700 4100 3600 3250 2800 2500 2000
Note: Multiply the gas volume by 0.62 for propane flow capacity in
ft 3 /hr. Multiply the propane flow capacity by 2500 Btu/ft
the propane Btu/hr capacity for a given pipe size and length.
LCD INSTALLATION AND OPERATION INSTRUCTIONS
3 /hr based on 0.60 specific gravity gas
Pipe length in feet
30 40 50 60 80
3
/hr)
130 115 105 90
245 215 195 170
500 440 400 350
760 670 610 530
3 to determine
Table 10 - Equivalent Pipe Length Chart
Nominal
Iron Pipe
Size, (in)
1"
"
1 1 /
4
"
1 1 /
2
2"
"
1
2 /
2
3"
Notes: 1. For flow through branch.
2. For flow at full open.
CAUTION: Always use a wrench on the gas valve
body when making gas connections to it. Never
over-tighten the piping entering the gas valve body
or gas valve failure may result!
Figure 16 - Gas Supply Piping
When applicable, provisions for vent, bleed and gas
relief lines must be made in accordance with the latest
revision of ANSI Z223.1/NFPA 54.
Safe lighting and other performance criteria were met
with the gas manifold and control assembly provided on
the boiler. All gas connections MUST be leak tested
before putting the boiler into operation.
WARNING: Never use an open flame to test for
gas leaks. Always use an approved leak
detection method. Failure to comply with this
warning can cause extensive property damage,
100 150
severe personal injury or death!
79 64
Whenever the gas supply piping is pressure tested the
150 120
boiler/water heater gas controls must be protected. If the
305 250
test pressure is equal to, or less than 1/2 psig, 3.5 kPa
460 380
isolate the boiler/water heater by closing it's manual shut
870 710
off valve, see Figure 16. If the test pressure is greater
than, or equal to 1/2 psig, 3.5 kPa , disconnect the
boiler/water heater and its individual shut-off valve.
Type of pipe fitting
1
90° Elbow Tee Gas Valve
Equivalent pipe length, (ft)
2.6 5.2
3.5 6.9
4.0 8.0
5.2 10.3
6.2 12.3
7.7 15.3
2 2
Gas Cock
0.6 1.5
0.8 1.9
0.9 2.3
1.2 3.0
1.4 3.7
1.8 4.5