Finned copper tube gas boilers & water heaters – Boiler Manual
20
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 Futera III 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 representative
to resolve the problem.
A minimum gas supply pressure of 2 in, 51mm, W.C.
natural or 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 11 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
11 should be used in conjunction with Table 12 to ensure that the
gas supply piping has the capacity to meet the demand.
Figure 18 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 11 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, (ft)
10
20
30
40
50
60
80
100 150
Maximum gas volume of pipe, (ft
3
/hr)
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 1270 1270 1150 990 870 710
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 12 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
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!
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. The main Dungs gas valve supplied with boiler/water
heater does not require external venting.
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.
Figure 18
Gas Supply Piping
