LCD Series Finned Copper Tube Gas Boilers & Water Heaters – Boiler Manual
24
GAS SUPPLY PIPING
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. Gas supply piping must
be in accordance with the National Fuel code, ANSI
Z223.1-latest revision or applicable provisions of the
local building codes. Canadian installations must
comply with CAN/CGA B149.1 or .2 Installation
Code. 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.
A minimum gas supply pressure of
7 in
,
178 mm
,
WC natural or
11 in
,
279 mm
WC propane and
maximum
14 in
,
356 mm
WC natural or propane,
must be available at the safety shutoff valve inlet with
the unit(s) operating.
Table 10 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
10 should be used in conjunction with Table 11 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. The manual shut-off valve
must be installed in the supply piping. It should be installed
5 ft
,
1.5 m
above the floor where required by local codes. 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 10 Gas pipe capacity
Maximum pipe capacity in ft
3
/hr based on 0.60 specific gravity gas
at a pressure of 0.5 psig or less and a 0.3" WC pressure drop.
Nominal
Iron Pipe
Size
Pipe length in feet
10
20
30
40
50
60
80
100
150
Maximum gas volume of pipe, (ft
3
/hr)
3/4"
278
190
152
130
115
105
90
79
64
1"
520
350
285
245
215
195
170
150
120
1 1/4"
1050 730
590
500
440
400
350
305
250
1 1/2"
1600 1100 890
760
670
610
530
460
380
2"
3050 2100 1650 1450 1270 1150 990
870
710
2 1/2"
4800 3300 2700 2300 2000 1850 1600 1400 1130
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
3
to determine
the propane Btu/hr capacity for a given pipe size and length.
Table 11 Equivalent pipe length chart
Nominal
Iron Pipe
Size
Type of pipe fitting
90˚ Elbow
Tee
1
Gate Valve
2
Gas Cock
2
Equivalent pipe length, (ft)
1"
2.6
5.2
0.6
1.5
1 1/4"
3.5
6.9
0.8
1.9
1 1/2"
4.0
8.0
0.9
2.3
2"
5.2
10.3
1.2
3.0
2 1/2"
6.2
12.3
1.4
3.7
3"
7.7
15.3
1.8
4.5
Notes:
1. For flow through branch.
2. For flow at full open.
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.
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, severe personal injury or death!
Whenever the gas supply piping is pressure tested the boiler/water
heater gas controls must be protected. If the test pressure is equal
to, or less than
1/2 psig
,
3.5 kPa
isolate the boiler/water heater
by closing it's manual shut 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.
